diff --git a/authenticate/authenticate.go b/authenticate/authenticate.go
index 88df09c2f..892e6e8bb 100644
--- a/authenticate/authenticate.go
+++ b/authenticate/authenticate.go
@@ -1,6 +1,7 @@
 package authenticate // import "github.com/pomerium/pomerium/authenticate"
 
 import (
+	"crypto/cipher"
 	"encoding/base64"
 	"errors"
 	"fmt"
@@ -20,10 +21,10 @@ const callbackPath = "/oauth2/callback"
 // ValidateOptions checks that configuration are complete and valid.
 // Returns on first error found.
 func ValidateOptions(o config.Options) error {
-	if _, err := cryptutil.NewCipherFromBase64(o.SharedKey); err != nil {
+	if _, err := cryptutil.NewAEADCipherFromBase64(o.SharedKey); err != nil {
 		return fmt.Errorf("authenticate: 'SHARED_SECRET' invalid: %v", err)
 	}
-	if _, err := cryptutil.NewCipherFromBase64(o.CookieSecret); err != nil {
+	if _, err := cryptutil.NewAEADCipherFromBase64(o.CookieSecret); err != nil {
 		return fmt.Errorf("authenticate: 'COOKIE_SECRET' invalid %v", err)
 	}
 	if err := urlutil.ValidateURL(o.AuthenticateURL); err != nil {
@@ -48,7 +49,8 @@ type Authenticate struct {
 	cookieSecret []byte
 	templates    *template.Template
 	sessionStore sessions.SessionStore
-	cipher       cryptutil.Cipher
+	cipher       cipher.AEAD
+	encoder      cryptutil.SecureEncoder
 	provider     identity.Authenticator
 }
 
@@ -58,7 +60,8 @@ func New(opts config.Options) (*Authenticate, error) {
 		return nil, err
 	}
 	decodedCookieSecret, _ := base64.StdEncoding.DecodeString(opts.CookieSecret)
-	cipher, err := cryptutil.NewCipher(decodedCookieSecret)
+	cipher, err := cryptutil.NewAEADCipher(decodedCookieSecret)
+	encoder := cryptutil.NewSecureJSONEncoder(cipher)
 	if err != nil {
 		return nil, err
 	}
@@ -72,7 +75,7 @@ func New(opts config.Options) (*Authenticate, error) {
 			CookieSecure:   opts.CookieSecure,
 			CookieHTTPOnly: opts.CookieHTTPOnly,
 			CookieExpire:   opts.CookieExpire,
-			CookieCipher:   cipher,
+			Encoder:        encoder,
 		})
 	if err != nil {
 		return nil, err
@@ -100,6 +103,7 @@ func New(opts config.Options) (*Authenticate, error) {
 		templates:    templates.New(),
 		sessionStore: cookieStore,
 		cipher:       cipher,
+		encoder:      encoder,
 		provider:     provider,
 		cookieSecret: decodedCookieSecret,
 		cookieName:   opts.CookieName,
diff --git a/authenticate/handlers.go b/authenticate/handlers.go
index 8e8e1a039..bcd798fb6 100644
--- a/authenticate/handlers.go
+++ b/authenticate/handlers.go
@@ -12,6 +12,7 @@ import (
 
 	"github.com/pomerium/csrf"
 
+	"github.com/pomerium/pomerium/internal/cryptutil"
 	"github.com/pomerium/pomerium/internal/httputil"
 	"github.com/pomerium/pomerium/internal/log"
 	"github.com/pomerium/pomerium/internal/middleware"
@@ -38,8 +39,8 @@ func (a *Authenticate) Handler() http.Handler {
 		a.cookieSecret,
 		csrf.Path("/"),
 		csrf.Domain(a.cookieDomain),
-		csrf.UnsafePaths([]string{"/oauth2/callback"}), // enforce CSRF on "safe" handler
-		csrf.FormValueName("state"),                    // rfc6749 section-10.12
+		csrf.UnsafePaths([]string{callbackPath}), // enforce CSRF on "safe" handler
+		csrf.FormValueName("state"),              // rfc6749 section-10.12
 		csrf.CookieName(fmt.Sprintf("%s_csrf", a.cookieName)),
 		csrf.ErrorHandler(http.HandlerFunc(httputil.CSRFFailureHandler)),
 	))
@@ -137,15 +138,21 @@ func (a *Authenticate) SignOut(w http.ResponseWriter, r *http.Request) {
 }
 
 // redirectToIdentityProvider starts the authenticate process by redirecting the
-// user to their respective identity provider.
-//
+// user to their respective identity provider. This function also builds the
+// 'state' parameter which is encrypted and includes authenticating data
+// for validation.
+// 'state' is : nonce|timestamp|redirect_url|encrypt(redirect_url)+mac(nonce,ts))
+
 // https://openid.net/specs/openid-connect-core-1_0-final.html#AuthRequest
 // https://tools.ietf.org/html/rfc6749#section-4.2.1
 func (a *Authenticate) redirectToIdentityProvider(w http.ResponseWriter, r *http.Request) {
 	redirectURL := a.RedirectURL.ResolveReference(r.URL)
 	nonce := csrf.Token(r)
-	state := fmt.Sprintf("%v:%v", nonce, redirectURL.String())
-	encodedState := base64.URLEncoding.EncodeToString([]byte(state))
+	now := time.Now().Unix()
+	b := []byte(fmt.Sprintf("%s|%d|", nonce, now))
+	enc := cryptutil.Encrypt(a.cipher, []byte(redirectURL.String()), b)
+	b = append(b, enc...)
+	encodedState := base64.URLEncoding.EncodeToString(b)
 	http.Redirect(w, r, a.provider.GetSignInURL(encodedState), http.StatusFound)
 }
 
@@ -187,19 +194,33 @@ func (a *Authenticate) getOAuthCallback(w http.ResponseWriter, r *http.Request)
 	if err != nil {
 		return nil, httputil.Error("malformed state", http.StatusBadRequest, err)
 	}
-	// split state into its it's components (nonce:redirect_uri)
-	statePayload := strings.SplitN(string(bytes), ":", 2)
-	if len(statePayload) != 2 {
-		return nil, fmt.Errorf("state malformed, size: %d", len(statePayload))
-	}
-	// parse redirect_uri; ignore csrf nonce (validity asserted by middleware)
-	redirectURL, err := urlutil.ParseAndValidateURL(statePayload[1])
-	if err != nil {
-		return nil, httputil.Error("invalid redirect uri", http.StatusBadRequest, err)
+
+	// split state into its it's components, e.g.
+	// (nonce|timestamp|redirect_url|encrypted_data(redirect_url)+mac(nonce,ts))
+	statePayload := strings.SplitN(string(bytes), "|", 3)
+	if len(statePayload) != 3 {
+		return nil, httputil.Error("'state' is malformed", http.StatusBadRequest,
+			fmt.Errorf("state malformed, size: %d", len(statePayload)))
 	}
 
-	// todo(bdd): if we want to be _extra_ sure, we can validate that the
-	// redirectURL hmac is valid. But the nonce should cover the integrity...
+	// verify that the returned timestamp is valid (replay attack)
+	if err := cryptutil.ValidTimestamp(statePayload[1]); err != nil {
+		return nil, httputil.Error(err.Error(), http.StatusBadRequest, err)
+	}
+
+	// Use our AEAD construct to enforce secrecy and authenticity,:
+	// mac: to validate the nonce again, and above timestamp
+	// decrypt: to prevent leaking 'redirect_uri' to IdP or logs)
+	b := []byte(fmt.Sprint(statePayload[0], "|", statePayload[1], "|"))
+	redirectString, err := cryptutil.Decrypt(a.cipher, []byte(statePayload[2]), b)
+	if err != nil {
+		return nil, httputil.Error("'state' has invalid hmac", http.StatusBadRequest, err)
+	}
+
+	redirectURL, err := urlutil.ParseAndValidateURL(string(redirectString))
+	if err != nil {
+		return nil, httputil.Error("'state' has invalid redirect uri", http.StatusBadRequest, err)
+	}
 
 	// OK. Looks good so let's persist our user session
 	if err := a.sessionStore.SaveSession(w, r, session); err != nil {
@@ -222,7 +243,7 @@ func (a *Authenticate) ExchangeToken(w http.ResponseWriter, r *http.Request) {
 		httputil.ErrorResponse(w, r, err)
 		return
 	}
-	encToken, err := sessions.MarshalSession(session, a.cipher)
+	encToken, err := sessions.MarshalSession(session, a.encoder)
 	if err != nil {
 		httputil.ErrorResponse(w, r, httputil.Error(err.Error(), http.StatusBadRequest, err))
 		return
diff --git a/authenticate/handlers_test.go b/authenticate/handlers_test.go
index 55c17430f..2524a4292 100644
--- a/authenticate/handlers_test.go
+++ b/authenticate/handlers_test.go
@@ -15,6 +15,7 @@ import (
 	"github.com/pomerium/pomerium/internal/identity"
 	"github.com/pomerium/pomerium/internal/sessions"
 	"github.com/pomerium/pomerium/internal/templates"
+	"golang.org/x/crypto/chacha20poly1305"
 )
 
 func testAuthenticate() *Authenticate {
@@ -73,22 +74,22 @@ func TestAuthenticate_SignIn(t *testing.T) {
 		session     sessions.SessionStore
 		restStore   sessions.SessionStore
 		provider    identity.MockProvider
-		cipher      cryptutil.Cipher
+		encoder     cryptutil.SecureEncoder
 		wantCode    int
 	}{
-		{"good", "state=example", "https://some.example", &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, identity.MockProvider{ValidateResponse: true}, &cryptutil.MockCipher{}, http.StatusFound},
-		{"session not valid", "state=example", "https://some.example", &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, identity.MockProvider{ValidateResponse: false}, &cryptutil.MockCipher{}, http.StatusFound},
-		{"session expired good refresh", "state=example", "https://some.example", &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(-10 * time.Second)}}, &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(-10 * time.Second)}}, identity.MockProvider{ValidateResponse: true, RefreshResponse: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(-10 * time.Second)}}, &cryptutil.MockCipher{}, http.StatusFound},
-		{"session expired bad refresh", "state=example", "https://some.example", &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(-10 * time.Second)}}, &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(-10 * time.Second)}}, identity.MockProvider{ValidateResponse: true, RefreshError: errors.New("error")}, &cryptutil.MockCipher{}, http.StatusFound}, // mocking hmac is meh
-		{"session expired bad refresh save", "state=example", "https://some.example", &sessions.MockSessionStore{SaveError: errors.New("ruh roh"), Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(-10 * time.Second)}}, &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(-10 * time.Second)}}, identity.MockProvider{ValidateResponse: true, RefreshResponse: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(-10 * time.Second)}}, &cryptutil.MockCipher{}, http.StatusFound},
+		{"good", "state=example", "https://some.example", &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, identity.MockProvider{ValidateResponse: true}, &cryptutil.MockEncoder{}, http.StatusFound},
+		{"session not valid", "state=example", "https://some.example", &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, identity.MockProvider{ValidateResponse: false}, &cryptutil.MockEncoder{}, http.StatusFound},
+		{"session expired good refresh", "state=example", "https://some.example", &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(-10 * time.Second)}}, &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(-10 * time.Second)}}, identity.MockProvider{ValidateResponse: true, RefreshResponse: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(-10 * time.Second)}}, &cryptutil.MockEncoder{}, http.StatusFound},
+		{"session expired bad refresh", "state=example", "https://some.example", &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(-10 * time.Second)}}, &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(-10 * time.Second)}}, identity.MockProvider{ValidateResponse: true, RefreshError: errors.New("error")}, &cryptutil.MockEncoder{}, http.StatusFound}, // mocking hmac is meh
+		{"session expired bad refresh save", "state=example", "https://some.example", &sessions.MockSessionStore{SaveError: errors.New("ruh roh"), Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(-10 * time.Second)}}, &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(-10 * time.Second)}}, identity.MockProvider{ValidateResponse: true, RefreshResponse: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(-10 * time.Second)}}, &cryptutil.MockEncoder{}, http.StatusFound},
 
-		// {"no cookie found trying to load", "state=example", "https://some.example", &sessions.MockSessionStore{LoadError: http.ErrNoCookie, Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, identity.MockProvider{ValidateResponse: true}, &cryptutil.MockCipher{}, http.StatusInternalServerError},
-		{"unexpected error trying to load session", "state=example", "https://some.example", &sessions.MockSessionStore{LoadError: errors.New("error"), Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, identity.MockProvider{ValidateResponse: true}, &cryptutil.MockCipher{}, http.StatusFound},
-		{"empty state", "state=", "https://some.example", &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, identity.MockProvider{ValidateResponse: true}, &cryptutil.MockCipher{}, http.StatusFound},
-		{"malformed redirect uri", "state=example", "https://accounts.google.^", &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, identity.MockProvider{ValidateResponse: true}, &cryptutil.MockCipher{}, http.StatusBadRequest},
+		// {"no cookie found trying to load", "state=example", "https://some.example", &sessions.MockSessionStore{LoadError: http.ErrNoCookie, Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, identity.MockProvider{ValidateResponse: true}, &cryptutil.MockEncoder{}, http.StatusInternalServerError},
+		{"unexpected error trying to load session", "state=example", "https://some.example", &sessions.MockSessionStore{LoadError: errors.New("error"), Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, identity.MockProvider{ValidateResponse: true}, &cryptutil.MockEncoder{}, http.StatusFound},
+		{"empty state", "state=", "https://some.example", &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, identity.MockProvider{ValidateResponse: true}, &cryptutil.MockEncoder{}, http.StatusFound},
+		{"malformed redirect uri", "state=example", "https://accounts.google.^", &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, identity.MockProvider{ValidateResponse: true}, &cryptutil.MockEncoder{}, http.StatusBadRequest},
 		// actually caught by go's handler, but we should keep the test.
-		{"bad redirect uri query", "state=nonce", "%gh&%ij", &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, identity.MockProvider{ValidateResponse: true}, &cryptutil.MockCipher{}, http.StatusBadRequest},
-		{"marshal session failure", "state=example", "https://some.example", &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, identity.MockProvider{ValidateResponse: true}, &cryptutil.MockCipher{MarshalError: errors.New("error")}, http.StatusFound},
+		{"bad redirect uri query", "state=nonce", "%gh&%ij", &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, identity.MockProvider{ValidateResponse: true}, &cryptutil.MockEncoder{}, http.StatusBadRequest},
+		{"marshal session failure", "state=example", "https://some.example", &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, &sessions.MockSessionStore{Session: &sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", RefreshDeadline: time.Now().Add(10 * time.Second)}}, identity.MockProvider{ValidateResponse: true}, &cryptutil.MockEncoder{MarshalError: errors.New("error")}, http.StatusFound},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -97,7 +98,7 @@ func TestAuthenticate_SignIn(t *testing.T) {
 				provider:     tt.provider,
 				RedirectURL:  uriParseHelper("https://some.example"),
 				SharedKey:    "secret",
-				cipher:       tt.cipher,
+				encoder:      tt.encoder,
 			}
 			uri := &url.URL{Host: "corp.some.example", Scheme: "https", Path: "/"}
 			uri.RawQuery = fmt.Sprintf("%s&redirect_uri=%s", tt.state, tt.redirectURI)
@@ -178,14 +179,19 @@ func TestAuthenticate_SignOut(t *testing.T) {
 
 func TestAuthenticate_OAuthCallback(t *testing.T) {
 	t.Parallel()
+
 	tests := []struct {
 		name   string
 		method string
 
-		// url params
-		paramErr        string
-		code            string
-		state           string
+		ts            int64
+		stateOvveride string
+		extraMac      string
+		extraState    string
+		paramErr      string
+		code          string
+		redirectURI   string
+
 		authenticateURL string
 		session         sessions.SessionStore
 		provider        identity.MockProvider
@@ -193,30 +199,52 @@ func TestAuthenticate_OAuthCallback(t *testing.T) {
 		want     string
 		wantCode int
 	}{
-		{"good", http.MethodGet, "", "code", base64.URLEncoding.EncodeToString([]byte("nonce:https://corp.pomerium.io")), "https://authenticate.pomerium.io", &sessions.MockSessionStore{}, identity.MockProvider{AuthenticateResponse: sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", Email: "blah@blah.com", RefreshDeadline: time.Now().Add(10 * time.Second)}}, "https://corp.pomerium.io", http.StatusFound},
-		{"failed authenticate", http.MethodGet, "", "code", base64.URLEncoding.EncodeToString([]byte("nonce:https://corp.pomerium.io")), "https://authenticate.pomerium.io", &sessions.MockSessionStore{}, identity.MockProvider{AuthenticateError: errors.New("error")}, "", http.StatusInternalServerError},
-		{"failed save session", http.MethodGet, "", "code", base64.URLEncoding.EncodeToString([]byte("nonce:https://corp.pomerium.io")), "https://authenticate.pomerium.io", &sessions.MockSessionStore{SaveError: errors.New("error")}, identity.MockProvider{AuthenticateResponse: sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", Email: "blah@blah.com", RefreshDeadline: time.Now().Add(10 * time.Second)}}, "", http.StatusInternalServerError},
-		{"provider returned error", http.MethodGet, "idp error", "code", base64.URLEncoding.EncodeToString([]byte("nonce:https://corp.pomerium.io")), "https://authenticate.pomerium.io", &sessions.MockSessionStore{}, identity.MockProvider{AuthenticateResponse: sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", Email: "blah@blah.com", RefreshDeadline: time.Now().Add(10 * time.Second)}}, "", http.StatusBadRequest},
-		{"empty code", http.MethodGet, "", "", base64.URLEncoding.EncodeToString([]byte("nonce:https://corp.pomerium.io")), "https://authenticate.pomerium.io", &sessions.MockSessionStore{}, identity.MockProvider{AuthenticateResponse: sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", Email: "blah@blah.com", RefreshDeadline: time.Now().Add(10 * time.Second)}}, "", http.StatusBadRequest},
-		{"invalid redirect uri", http.MethodGet, "", "code", base64.URLEncoding.EncodeToString([]byte("nonce:corp.pomerium.io")), "https://authenticate.pomerium.io", &sessions.MockSessionStore{}, identity.MockProvider{AuthenticateResponse: sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", Email: "blah@blah.com", RefreshDeadline: time.Now().Add(10 * time.Second)}}, "", http.StatusBadRequest},
-		{"bad redirect uri", http.MethodGet, "", "code", base64.URLEncoding.EncodeToString([]byte("nonce:http://^^^")), "https://authenticate.pomerium.io", &sessions.MockSessionStore{}, identity.MockProvider{AuthenticateResponse: sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", Email: "blah@blah.com", RefreshDeadline: time.Now().Add(10 * time.Second)}}, "https://corp.pomerium.io", http.StatusBadRequest},
-		{"bad base64 state", http.MethodGet, "", "code", base64.URLEncoding.EncodeToString([]byte("nonce:https://corp.pomerium.io")) + "%", "https://authenticate.pomerium.io", &sessions.MockSessionStore{}, identity.MockProvider{AuthenticateResponse: sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", Email: "blah@blah.com", RefreshDeadline: time.Now().Add(10 * time.Second)}}, "https://corp.pomerium.io", http.StatusBadRequest},
-		{"too many state delimeters", http.MethodGet, "", "code", base64.URLEncoding.EncodeToString([]byte("nonce:https://corp.pomerium.io:wait")), "https://authenticate.pomerium.io", &sessions.MockSessionStore{}, identity.MockProvider{AuthenticateResponse: sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", Email: "blah@blah.com", RefreshDeadline: time.Now().Add(10 * time.Second)}}, "https://corp.pomerium.io", http.StatusBadRequest},
-		{"too few state delimeters", http.MethodGet, "", "code", base64.URLEncoding.EncodeToString([]byte("nonce")), "https://authenticate.pomerium.io", &sessions.MockSessionStore{}, identity.MockProvider{AuthenticateResponse: sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", Email: "blah@blah.com", RefreshDeadline: time.Now().Add(10 * time.Second)}}, "https://corp.pomerium.io", http.StatusInternalServerError},
+		{"good", http.MethodGet, time.Now().Unix(), "", "", "", "", "code", "https://corp.pomerium.io", "https://authenticate.pomerium.io", &sessions.MockSessionStore{}, identity.MockProvider{AuthenticateResponse: sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", Email: "blah@blah.com", RefreshDeadline: time.Now().Add(10 * time.Second)}}, "https://corp.pomerium.io", http.StatusFound},
+		{"failed authenticate", http.MethodGet, time.Now().Unix(), "", "", "", "", "code", "https://corp.pomerium.io", "https://authenticate.pomerium.io", &sessions.MockSessionStore{}, identity.MockProvider{AuthenticateError: errors.New("error")}, "", http.StatusInternalServerError},
+		{"failed save session", http.MethodGet, time.Now().Unix(), "", "", "", "", "code", "https://corp.pomerium.io", "https://authenticate.pomerium.io", &sessions.MockSessionStore{SaveError: errors.New("error")}, identity.MockProvider{AuthenticateResponse: sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", Email: "blah@blah.com", RefreshDeadline: time.Now().Add(10 * time.Second)}}, "", http.StatusInternalServerError},
+		{"provider returned error", http.MethodGet, time.Now().Unix(), "", "", "", "idp error", "code", "https://corp.pomerium.io", "https://authenticate.pomerium.io", &sessions.MockSessionStore{}, identity.MockProvider{AuthenticateResponse: sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", Email: "blah@blah.com", RefreshDeadline: time.Now().Add(10 * time.Second)}}, "", http.StatusBadRequest},
+		{"empty code", http.MethodGet, time.Now().Unix(), "", "", "", "", "", "https://corp.pomerium.io", "https://authenticate.pomerium.io", &sessions.MockSessionStore{}, identity.MockProvider{AuthenticateResponse: sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", Email: "blah@blah.com", RefreshDeadline: time.Now().Add(10 * time.Second)}}, "", http.StatusBadRequest},
+		{"invalid redirect uri", http.MethodGet, time.Now().Unix(), "", "", "", "", "code", "corp.pomerium.io", "https://authenticate.pomerium.io", &sessions.MockSessionStore{}, identity.MockProvider{AuthenticateResponse: sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", Email: "blah@blah.com", RefreshDeadline: time.Now().Add(10 * time.Second)}}, "", http.StatusBadRequest},
+		{"bad redirect uri", http.MethodGet, time.Now().Unix(), "", "", "", "", "code", "http://^^^", "https://authenticate.pomerium.io", &sessions.MockSessionStore{}, identity.MockProvider{AuthenticateResponse: sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", Email: "blah@blah.com", RefreshDeadline: time.Now().Add(10 * time.Second)}}, "https://corp.pomerium.io", http.StatusBadRequest},
+		{"bad timing - too soon", http.MethodGet, time.Now().Add(1 * time.Hour).Unix(), "", "", "", "", "code", "https://corp.pomerium.io", "https://authenticate.pomerium.io", &sessions.MockSessionStore{}, identity.MockProvider{AuthenticateResponse: sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", Email: "blah@blah.com", RefreshDeadline: time.Now().Add(10 * time.Second)}}, "https://corp.pomerium.io", http.StatusBadRequest},
+		{"bad timing - expired", http.MethodGet, time.Now().Add(-1 * time.Hour).Unix(), "", "", "", "", "code", "https://corp.pomerium.io", "https://authenticate.pomerium.io", &sessions.MockSessionStore{}, identity.MockProvider{AuthenticateResponse: sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", Email: "blah@blah.com", RefreshDeadline: time.Now().Add(10 * time.Second)}}, "https://corp.pomerium.io", http.StatusBadRequest},
+		{"bad base64", http.MethodGet, time.Now().Unix(), "", "", "^", "", "code", "https://corp.pomerium.io", "https://authenticate.pomerium.io", &sessions.MockSessionStore{}, identity.MockProvider{AuthenticateResponse: sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", Email: "blah@blah.com", RefreshDeadline: time.Now().Add(10 * time.Second)}}, "https://corp.pomerium.io", http.StatusBadRequest},
+		{"too many seperators", http.MethodGet, time.Now().Unix(), "", "", "|ok|now|what", "", "code", "https://corp.pomerium.io", "https://authenticate.pomerium.io", &sessions.MockSessionStore{}, identity.MockProvider{AuthenticateResponse: sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", Email: "blah@blah.com", RefreshDeadline: time.Now().Add(10 * time.Second)}}, "https://corp.pomerium.io", http.StatusBadRequest},
+		{"bad hmac", http.MethodGet, time.Now().Unix(), "", "NOTMAC", "", "", "code", "https://corp.pomerium.io", "https://authenticate.pomerium.io", &sessions.MockSessionStore{}, identity.MockProvider{AuthenticateResponse: sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", Email: "blah@blah.com", RefreshDeadline: time.Now().Add(10 * time.Second)}}, "https://corp.pomerium.io", http.StatusBadRequest},
+		{"bad hmac", http.MethodGet, time.Now().Unix(), base64.URLEncoding.EncodeToString([]byte("malformed_state")), "", "", "", "code", "https://corp.pomerium.io", "https://authenticate.pomerium.io", &sessions.MockSessionStore{}, identity.MockProvider{AuthenticateResponse: sessions.State{AccessToken: "AccessToken", RefreshToken: "RefreshToken", Email: "blah@blah.com", RefreshDeadline: time.Now().Add(10 * time.Second)}}, "https://corp.pomerium.io", http.StatusBadRequest},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
+			aead, err := chacha20poly1305.NewX(cryptutil.NewKey())
+			if err != nil {
+				t.Fatal(err)
+			}
 			authURL, _ := url.Parse(tt.authenticateURL)
 			a := &Authenticate{
 				RedirectURL:  authURL,
 				sessionStore: tt.session,
 				provider:     tt.provider,
+				cipher:       aead,
 			}
 			u, _ := url.Parse("/oauthGet")
 			params, _ := url.ParseQuery(u.RawQuery)
 			params.Add("error", tt.paramErr)
 			params.Add("code", tt.code)
-			params.Add("state", tt.state)
+			nonce := cryptutil.NewBase64Key() // mock csrf
+
+			// (nonce|timestamp|redirect_url|encrypt(redirect_url),mac(nonce,ts))
+			b := []byte(fmt.Sprintf("%s|%d|%s", nonce, tt.ts, tt.extraMac))
+
+			enc := cryptutil.Encrypt(a.cipher, []byte(tt.redirectURI), b)
+			b = append(b, enc...)
+			encodedState := base64.URLEncoding.EncodeToString(b)
+			if tt.extraState != "" {
+				encodedState += tt.extraState
+			}
+			if tt.stateOvveride != "" {
+				encodedState = tt.stateOvveride
+			}
+			params.Add("state", encodedState)
 
 			u.RawQuery = params.Encode()
 
@@ -240,22 +268,27 @@ func TestAuthenticate_ExchangeToken(t *testing.T) {
 		method    string
 		idToken   string
 		restStore sessions.SessionStore
-		cipher    cryptutil.Cipher
+		encoder   cryptutil.SecureEncoder
 		provider  identity.MockProvider
 		want      string
 	}{
-		{"good", http.MethodPost, "token", &sessions.MockSessionStore{}, &cryptutil.MockCipher{}, identity.MockProvider{IDTokenToSessionResponse: sessions.State{IDToken: "ok"}}, ""},
-		{"could not exchange identity for session", http.MethodPost, "token", &sessions.MockSessionStore{}, &cryptutil.MockCipher{}, identity.MockProvider{IDTokenToSessionError: errors.New("error")}, ""},
-		{"missing token", http.MethodPost, "", &sessions.MockSessionStore{}, &cryptutil.MockCipher{}, identity.MockProvider{IDTokenToSessionResponse: sessions.State{IDToken: "ok"}}, "missing id token"},
-		{"malformed form", http.MethodPost, "token", &sessions.MockSessionStore{}, &cryptutil.MockCipher{}, identity.MockProvider{IDTokenToSessionResponse: sessions.State{IDToken: "ok"}}, ""},
-		{"can't marshal token", http.MethodPost, "token", &sessions.MockSessionStore{}, &cryptutil.MockCipher{MarshalError: errors.New("can't marshal token")}, identity.MockProvider{IDTokenToSessionResponse: sessions.State{IDToken: "ok"}}, "can't marshal token"},
+		{"good", http.MethodPost, "token", &sessions.MockSessionStore{}, &cryptutil.MockEncoder{}, identity.MockProvider{IDTokenToSessionResponse: sessions.State{IDToken: "ok"}}, ""},
+		{"could not exchange identity for session", http.MethodPost, "token", &sessions.MockSessionStore{}, &cryptutil.MockEncoder{}, identity.MockProvider{IDTokenToSessionError: errors.New("error")}, ""},
+		{"missing token", http.MethodPost, "", &sessions.MockSessionStore{}, &cryptutil.MockEncoder{}, identity.MockProvider{IDTokenToSessionResponse: sessions.State{IDToken: "ok"}}, "missing id token"},
+		{"malformed form", http.MethodPost, "token", &sessions.MockSessionStore{}, &cryptutil.MockEncoder{}, identity.MockProvider{IDTokenToSessionResponse: sessions.State{IDToken: "ok"}}, ""},
+		{"can't marshal token", http.MethodPost, "token", &sessions.MockSessionStore{}, &cryptutil.MockEncoder{MarshalError: errors.New("can't marshal token")}, identity.MockProvider{IDTokenToSessionResponse: sessions.State{IDToken: "ok"}}, "can't marshal token"},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
+			aead, err := chacha20poly1305.NewX(cryptutil.NewKey())
+			if err != nil {
+				t.Fatal(err)
+			}
 			a := &Authenticate{
-				cipher:       tt.cipher,
+				encoder:      tt.encoder,
 				provider:     tt.provider,
 				sessionStore: tt.restStore,
+				cipher:       aead,
 			}
 			form := url.Values{}
 			if tt.idToken != "" {
@@ -282,6 +315,7 @@ func TestAuthenticate_ExchangeToken(t *testing.T) {
 }
 
 func TestAuthenticate_SessionValidatorMiddleware(t *testing.T) {
+	t.Parallel()
 	fn := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", "text/plain; charset=utf-8")
 		w.Header().Set("X-Content-Type-Options", "nosniff")
@@ -305,13 +339,17 @@ func TestAuthenticate_SessionValidatorMiddleware(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-
+			aead, err := chacha20poly1305.NewX(cryptutil.NewKey())
+			if err != nil {
+				t.Fatal(err)
+			}
 			a := Authenticate{
 				SharedKey:    "80ldlrU2d7w+wVpKNfevk6fmb8otEx6CqOfshj2LwhQ=",
 				cookieSecret: []byte("80ldlrU2d7w+wVpKNfevk6fmb8otEx6CqOfshj2LwhQ="),
 				RedirectURL:  uriParseHelper("https://authenticate.corp.beyondperimeter.com"),
 				sessionStore: tt.session,
 				provider:     tt.provider,
+				cipher:       aead,
 			}
 			r := httptest.NewRequest("GET", "/", nil)
 			state, _ := tt.session.LoadSession(r)
diff --git a/docs/docs/CHANGELOG.md b/docs/docs/CHANGELOG.md
index f778e156a..3610c8ca0 100644
--- a/docs/docs/CHANGELOG.md
+++ b/docs/docs/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### Security
 
+- The user's original intended location before completing the authentication process is now encrypted and kept confidential from the identity provider. [GH-316](https://github.com/pomerium/pomerium/pull/316)
 - Under certain circumstances, where debug logging was enabled, pomerium's shared secret could be leaked to http access logs as a query param.
 
 ### Fixed
diff --git a/go.mod b/go.mod
index efd3cc42a..21e0cfc8b 100644
--- a/go.mod
+++ b/go.mod
@@ -14,7 +14,7 @@ require (
 	github.com/magiconair/properties v1.8.1 // indirect
 	github.com/mitchellh/hashstructure v1.0.0
 	github.com/pelletier/go-toml v1.4.0 // indirect
-	github.com/pomerium/csrf v1.6.2-0.20190911035354-d4d212209a30
+	github.com/pomerium/csrf v1.6.2-0.20190918035251-f3318380bad3
 	github.com/pomerium/go-oidc v2.0.0+incompatible
 	github.com/pquerna/cachecontrol v0.0.0-20180517163645-1555304b9b35 // indirect
 	github.com/prometheus/client_golang v0.9.3
diff --git a/go.sum b/go.sum
index a7e0bfde8..5583db503 100644
--- a/go.sum
+++ b/go.sum
@@ -126,6 +126,8 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/pomerium/csrf v1.6.2-0.20190911035354-d4d212209a30 h1:jggCv6hZvcxjGa3gqkYY2EUuOkITI9Znugz/f3QJfRQ=
 github.com/pomerium/csrf v1.6.2-0.20190911035354-d4d212209a30/go.mod h1:UE2U4JOsjXNeq+MX/lqhZpUFsNAxbXERuYsWK2iULh0=
+github.com/pomerium/csrf v1.6.2-0.20190918035251-f3318380bad3 h1:FmzFXnCAepHZwl6QPhTFqBHcbcGevdiEQjutK+M5bj4=
+github.com/pomerium/csrf v1.6.2-0.20190918035251-f3318380bad3/go.mod h1:UE2U4JOsjXNeq+MX/lqhZpUFsNAxbXERuYsWK2iULh0=
 github.com/pomerium/go-oidc v2.0.0+incompatible h1:gVvG/ExWsHQqatV+uceROnGmbVYF44mDNx5nayBhC0o=
 github.com/pomerium/go-oidc v2.0.0+incompatible/go.mod h1:DRsGVw6MOgxbfq4Y57jKOE8lbEfayxeiY0A8/4vxjBM=
 github.com/pquerna/cachecontrol v0.0.0-20180517163645-1555304b9b35 h1:J9b7z+QKAmPf4YLrFg6oQUotqHQeUNWwkvo7jZp1GLU=
@@ -196,6 +198,7 @@ golang.org/x/crypto v0.0.0-20190605123033-f99c8df09eb5 h1:58fnuSXlxZmFdJyvtTFVmV
 golang.org/x/crypto v0.0.0-20190605123033-f99c8df09eb5/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20190611184440-5c40567a22f8 h1:1wopBVtVdWnn03fZelqdXTqk7U7zPQCb+T4rbU9ZEoU=
 golang.org/x/crypto v0.0.0-20190611184440-5c40567a22f8/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
+golang.org/x/crypto v0.0.0-20190911031432-227b76d455e7 h1:0hQKqeLdqlt5iIwVOBErRisrHJAN57yOiPRQItI20fU=
 golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=
 golang.org/x/lint v0.0.0-20190227174305-5b3e6a55c961/go.mod h1:wehouNa3lNwaWXcvxsM5YxQ5yQlVC4a0KAMCusXpPoU=
diff --git a/internal/cryptutil/encrypt.go b/internal/cryptutil/encrypt.go
index f49cb16e8..caa6db7f8 100644
--- a/internal/cryptutil/encrypt.go
+++ b/internal/cryptutil/encrypt.go
@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"compress/gzip"
 	"crypto/cipher"
-	"crypto/rand"
 	"encoding/base64"
 	"encoding/json"
 	"fmt"
@@ -13,122 +12,47 @@ import (
 	"golang.org/x/crypto/chacha20poly1305"
 )
 
-// DefaultKeySize is the default key size in bytes.
-const DefaultKeySize = 32
-
-// NewKey generates a random 32-byte key.
-//
-// Panics if source of randomness fails.
-func NewKey() []byte {
-	return randomBytes(DefaultKeySize)
-}
-
-// NewBase64Key generates a random base64 encoded 32-byte key.
-//
-// Panics if source of randomness fails.
-func NewBase64Key() string {
-	return NewRandomStringN(DefaultKeySize)
-}
-
-// NewRandomStringN returns base64 encoded random string of a given num of bytes.
-//
-// Panics if source of randomness fails.
-func NewRandomStringN(c int) string {
-	return base64.StdEncoding.EncodeToString(randomBytes(c))
-}
-
-func randomBytes(c int) []byte {
-	if c < 0 {
-		c = DefaultKeySize
+// NewAEADCipher takes secret key and returns a new XChacha20poly1305 cipher.
+func NewAEADCipher(secret []byte) (cipher.AEAD, error) {
+	if len(secret) != 32 {
+		return nil, fmt.Errorf("cryptutil: got %d bytes but want 32", len(secret))
 	}
-	b := make([]byte, c)
-	if _, err := rand.Read(b); err != nil {
-		panic(err)
-	}
-	return b
+	return chacha20poly1305.NewX(secret)
+
 }
 
-// Cipher provides methods to encrypt and decrypt values.
-type Cipher interface {
-	Encrypt([]byte) ([]byte, error)
-	Decrypt([]byte) ([]byte, error)
-	Marshal(interface{}) (string, error)
-	Unmarshal(string, interface{}) error
-}
-
-// XChaCha20Cipher provides methods to encrypt and decrypt values.
-// Using an AEAD is a cipher providing authenticated encryption with associated data.
-// For a description of the methodology, see https://en.wikipedia.org/wiki/Authenticated_encryption
-type XChaCha20Cipher struct {
-	aead cipher.AEAD
-}
-
-// NewCipher takes secret key and returns a new XChacha20poly1305 cipher.
-func NewCipher(secret []byte) (*XChaCha20Cipher, error) {
-	aead, err := chacha20poly1305.NewX(secret)
-	if err != nil {
-		return nil, err
-	}
-	return &XChaCha20Cipher{
-		aead: aead,
-	}, nil
-}
-
-// NewCipherFromBase64 takes a base64 encoded secret key and returns a new XChacha20poly1305 cipher.
-func NewCipherFromBase64(s string) (*XChaCha20Cipher, error) {
+// NewAEADCipherFromBase64 takes a base64 encoded secret key and returns a new XChacha20poly1305 cipher.
+func NewAEADCipherFromBase64(s string) (cipher.AEAD, error) {
 	decoded, err := base64.StdEncoding.DecodeString(s)
 	if err != nil {
 		return nil, fmt.Errorf("cryptutil: invalid base64: %v", err)
 	}
-	if len(decoded) != 32 {
-		return nil, fmt.Errorf("cryptutil: got %d bytes but want 32", len(decoded))
-	}
-	return NewCipher(decoded)
+	return NewAEADCipher(decoded)
 }
 
-// GenerateNonce generates a random nonce.
-// Panics if source of randomness fails.
-func (c *XChaCha20Cipher) GenerateNonce() []byte {
-	return randomBytes(c.aead.NonceSize())
+// SecureEncoder provides and interface for to encrypt and decrypting structures .
+type SecureEncoder interface {
+	Marshal(interface{}) (string, error)
+	Unmarshal(string, interface{}) error
 }
 
-// Encrypt a value using XChaCha20-Poly1305
-func (c *XChaCha20Cipher) Encrypt(plaintext []byte) (joined []byte, err error) {
-	defer func() {
-		if r := recover(); r != nil {
-			err = fmt.Errorf("cryptutil: error encrypting bytes: %v", r)
-		}
-	}()
-	nonce := c.GenerateNonce()
-
-	ciphertext := c.aead.Seal(nil, nonce, plaintext, nil)
-
-	// we return the nonce as part of the returned value
-	joined = append(ciphertext, nonce...)
-	return joined, nil
+// SecureJSONEncoder implements SecureEncoder for JSON using an AEAD cipher.
+//
+// See https://en.wikipedia.org/wiki/Authenticated_encryption
+type SecureJSONEncoder struct {
+	aead cipher.AEAD
 }
 
-// Decrypt a value using XChaCha20-Poly1305
-func (c *XChaCha20Cipher) Decrypt(joined []byte) ([]byte, error) {
-	if len(joined) <= c.aead.NonceSize() {
-		return nil, fmt.Errorf("cryptutil: invalid input size: %d", len(joined))
-	}
-	// grab out the nonce
-	pivot := len(joined) - c.aead.NonceSize()
-	ciphertext := joined[:pivot]
-	nonce := joined[pivot:]
-
-	plaintext, err := c.aead.Open(nil, nonce, ciphertext, nil)
-	if err != nil {
-		return nil, err
-	}
-
-	return plaintext, nil
+// NewSecureJSONEncoder takes a base64 encoded secret key and returns a new XChacha20poly1305 cipher.
+func NewSecureJSONEncoder(aead cipher.AEAD) SecureEncoder {
+	return &SecureJSONEncoder{aead: aead}
 }
 
 // Marshal marshals the interface state as JSON, encrypts the JSON using the cipher
 // and base64 encodes the binary value as a string and returns the result
-func (c *XChaCha20Cipher) Marshal(s interface{}) (string, error) {
+//
+// can panic if source of random entropy is exhausted generating a nonce.
+func (c *SecureJSONEncoder) Marshal(s interface{}) (string, error) {
 	// encode json value
 	plaintext, err := json.Marshal(s)
 	if err != nil {
@@ -140,10 +64,8 @@ func (c *XChaCha20Cipher) Marshal(s interface{}) (string, error) {
 		return "", err
 	}
 	// encrypt the compressed JSON bytes
-	ciphertext, err := c.Encrypt(compressed)
-	if err != nil {
-		return "", err
-	}
+	ciphertext := Encrypt(c.aead, compressed, nil)
+
 	// base64-encode the result
 	encoded := base64.RawURLEncoding.EncodeToString(ciphertext)
 	return encoded, nil
@@ -151,14 +73,14 @@ func (c *XChaCha20Cipher) Marshal(s interface{}) (string, error) {
 
 // Unmarshal takes the marshaled string, base64-decodes into a byte slice, decrypts the
 // byte slice the passed cipher, and unmarshals the resulting JSON into the struct pointer passed
-func (c *XChaCha20Cipher) Unmarshal(value string, s interface{}) error {
+func (c *SecureJSONEncoder) Unmarshal(value string, s interface{}) error {
 	// convert base64 string value to bytes
 	ciphertext, err := base64.RawURLEncoding.DecodeString(value)
 	if err != nil {
 		return err
 	}
 	// decrypt the bytes
-	compressed, err := c.Decrypt(ciphertext)
+	compressed, err := Decrypt(c.aead, ciphertext, nil)
 	if err != nil {
 		return err
 	}
@@ -172,10 +94,10 @@ func (c *XChaCha20Cipher) Unmarshal(value string, s interface{}) error {
 	if err != nil {
 		return err
 	}
-
 	return nil
 }
 
+// compress gzips a set of bytes
 func compress(data []byte) ([]byte, error) {
 	var buf bytes.Buffer
 	writer, err := gzip.NewWriterLevel(&buf, gzip.DefaultCompression)
@@ -194,6 +116,7 @@ func compress(data []byte) ([]byte, error) {
 	return buf.Bytes(), nil
 }
 
+// decompress un-gzips a set of bytes
 func decompress(data []byte) ([]byte, error) {
 	reader, err := gzip.NewReader(bytes.NewReader(data))
 	if err != nil {
@@ -206,3 +129,27 @@ func decompress(data []byte) ([]byte, error) {
 	}
 	return buf.Bytes(), nil
 }
+
+// Encrypt encrypts a value with optional associated data
+//
+// Panics if source of randomness fails.
+func Encrypt(a cipher.AEAD, data, ad []byte) []byte {
+	iv := randomBytes(a.NonceSize())
+	ciphertext := a.Seal(nil, iv, data, ad)
+	return append(ciphertext, iv...)
+}
+
+// Decrypt a value with optional associated data
+func Decrypt(a cipher.AEAD, data, ad []byte) ([]byte, error) {
+	if len(data) <= a.NonceSize() {
+		return nil, fmt.Errorf("cryptutil: invalid input size: %d", len(data))
+	}
+	size := len(data) - a.NonceSize()
+	ciphertext := data[:size]
+	nonce := data[size:]
+	plaintext, err := a.Open(nil, nonce, ciphertext, ad)
+	if err != nil {
+		return nil, err
+	}
+	return plaintext, nil
+}
diff --git a/internal/cryptutil/encrypt_test.go b/internal/cryptutil/encrypt_test.go
index dc5671f51..88b9b7003 100644
--- a/internal/cryptutil/encrypt_test.go
+++ b/internal/cryptutil/encrypt_test.go
@@ -1,12 +1,8 @@
 package cryptutil
 
 import (
-	"crypto/rand"
-	"crypto/sha1"
 	"encoding/base64"
-	"fmt"
 	"reflect"
-	"sync"
 	"testing"
 )
 
@@ -14,27 +10,24 @@ func TestEncodeAndDecodeAccessToken(t *testing.T) {
 	plaintext := []byte("my plain text value")
 
 	key := NewKey()
-	c, err := NewCipher(key)
+	c, err := NewAEADCipher(key)
 	if err != nil {
 		t.Fatalf("unexpected err: %v", err)
 	}
 
-	ciphertext, err := c.Encrypt(plaintext)
-	if err != nil {
-		t.Fatalf("unexpected err: %v", err)
-	}
+	ciphertext := Encrypt(c, plaintext, nil)
 
 	if reflect.DeepEqual(plaintext, ciphertext) {
 		t.Fatalf("plaintext is not encrypted plaintext:%v ciphertext:%x", plaintext, ciphertext)
 	}
 
-	got, err := c.Decrypt(ciphertext)
+	got, err := Decrypt(c, ciphertext, nil)
 	if err != nil {
 		t.Fatalf("unexpected err decrypting: %v", err)
 	}
 
 	// if less than 32 bytes, fail
-	_, err = c.Decrypt([]byte("oh"))
+	_, err = Decrypt(c, []byte("oh"), nil)
 	if err == nil {
 		t.Fatalf("should fail if <32 bytes output: %v", err)
 	}
@@ -49,10 +42,11 @@ func TestEncodeAndDecodeAccessToken(t *testing.T) {
 func TestMarshalAndUnmarshalStruct(t *testing.T) {
 	key := NewKey()
 
-	c, err := NewCipher(key)
+	a, err := NewAEADCipher(key)
 	if err != nil {
 		t.Fatalf("unexpected err: %v", err)
 	}
+	c := SecureJSONEncoder{aead: a}
 
 	type TC struct {
 		Field string `json:"field"`
@@ -101,102 +95,7 @@ func TestMarshalAndUnmarshalStruct(t *testing.T) {
 	}
 }
 
-func TestCipherDataRace(t *testing.T) {
-	cipher, err := NewCipher(NewKey())
-	if err != nil {
-		t.Fatalf("unexpected generating cipher err: %v", err)
-	}
-
-	type TC struct {
-		Field string `json:"field"`
-	}
-
-	wg := &sync.WaitGroup{}
-	for i := 0; i < 100; i++ {
-		wg.Add(1)
-		go func(c *XChaCha20Cipher, wg *sync.WaitGroup) {
-			defer wg.Done()
-			b := make([]byte, 32)
-			_, err := rand.Read(b)
-			if err != nil {
-				t.Fatalf("unexecpted error reading random bytes: %v", err)
-			}
-
-			sha := fmt.Sprintf("%x", sha1.New().Sum(b))
-			tc := &TC{
-				Field: sha,
-			}
-
-			value1, err := c.Marshal(tc)
-			if err != nil {
-				t.Fatalf("unexpected err: %v", err)
-			}
-
-			value2, err := c.Marshal(tc)
-			if err != nil {
-				t.Fatalf("unexpected err: %v", err)
-			}
-
-			if value1 == value2 {
-				t.Fatalf("expected marshaled values to not be equal %v != %v", value1, value2)
-			}
-
-			got1 := &TC{}
-			err = c.Unmarshal(value1, got1)
-			if err != nil {
-				t.Fatalf("unexpected err unmarshalling struct: %v", err)
-			}
-
-			if !reflect.DeepEqual(got1, tc) {
-				t.Logf("want: %#v", tc)
-				t.Logf(" got: %#v", got1)
-				t.Fatalf("expected structs to be equal")
-			}
-
-			got2 := &TC{}
-			err = c.Unmarshal(value2, got2)
-			if err != nil {
-				t.Fatalf("unexpected err unmarshalling struct: %v", err)
-			}
-
-			if !reflect.DeepEqual(got1, got2) {
-				t.Logf("got2: %#v", got2)
-				t.Logf("got1: %#v", got1)
-				t.Fatalf("expected structs to be equal")
-			}
-
-		}(cipher, wg)
-	}
-	wg.Wait()
-}
-
-func TestGenerateRandomString(t *testing.T) {
-	t.Parallel()
-	tests := []struct {
-		name string
-		c    int
-		want int
-	}{
-		{"simple", 32, 32},
-		{"zero", 0, 0},
-		{"negative", -1, 32},
-	}
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			o := NewRandomStringN(tt.c)
-			b, err := base64.StdEncoding.DecodeString(o)
-			if err != nil {
-				t.Error(err)
-			}
-			got := len(b)
-			if got != tt.want {
-				t.Errorf("NewRandomStringN() = %d, want %d", got, tt.want)
-			}
-		})
-	}
-}
-
-func TestXChaCha20Cipher_Marshal(t *testing.T) {
+func TestSecureJSONEncoder_Marshal(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		name    string
@@ -225,20 +124,22 @@ func TestXChaCha20Cipher_Marshal(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 
-			c, err := NewCipher(NewKey())
+			c, err := NewAEADCipher(NewKey())
 			if err != nil {
 				t.Fatalf("unexpected err: %v", err)
 			}
-			_, err = c.Marshal(tt.s)
+			e := SecureJSONEncoder{aead: c}
+
+			_, err = e.Marshal(tt.s)
 			if (err != nil) != tt.wantErr {
-				t.Errorf("XChaCha20Cipher.Marshal() error = %v, wantErr %v", err, tt.wantErr)
+				t.Errorf("SecureJSONEncoder.Marshal() error = %v, wantErr %v", err, tt.wantErr)
 				return
 			}
 		})
 	}
 }
 
-func TestNewCipher(t *testing.T) {
+func TestNewAEADCipher(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		name    string
@@ -251,16 +152,16 @@ func TestNewCipher(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			_, err := NewCipher(tt.secret)
+			_, err := NewAEADCipher(tt.secret)
 			if (err != nil) != tt.wantErr {
-				t.Errorf("NewCipher() error = %v, wantErr %v", err, tt.wantErr)
+				t.Errorf("NewAEADCipher() error = %v, wantErr %v", err, tt.wantErr)
 				return
 			}
 		})
 	}
 }
 
-func TestNewCipherFromBase64(t *testing.T) {
+func TestNewAEADCipherFromBase64(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		name    string
@@ -274,34 +175,11 @@ func TestNewCipherFromBase64(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			_, err := NewCipherFromBase64(tt.s)
+			_, err := NewAEADCipherFromBase64(tt.s)
 			if (err != nil) != tt.wantErr {
-				t.Errorf("NewCipherFromBase64() error = %v, wantErr %v", err, tt.wantErr)
+				t.Errorf("NewAEADCipherFromBase64() error = %v, wantErr %v", err, tt.wantErr)
 				return
 			}
 		})
 	}
 }
-
-func TestNewBase64Key(t *testing.T) {
-	t.Parallel()
-	tests := []struct {
-		name string
-		want int
-	}{
-		{"simple", 32},
-	}
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			o := NewBase64Key()
-			b, err := base64.StdEncoding.DecodeString(o)
-			if err != nil {
-				t.Error(err)
-			}
-			got := len(b)
-			if got != tt.want {
-				t.Errorf("NewBase64Key() = %d, want %d", got, tt.want)
-			}
-		})
-	}
-}
diff --git a/internal/cryptutil/helpers.go b/internal/cryptutil/helpers.go
new file mode 100644
index 000000000..8b9e6cb86
--- /dev/null
+++ b/internal/cryptutil/helpers.go
@@ -0,0 +1,45 @@
+package cryptutil // import "github.com/pomerium/pomerium/internal/cryptutil"
+
+import (
+	"crypto/rand"
+	"encoding/base64"
+)
+
+// DefaultKeySize is the default key size in bytes.
+const DefaultKeySize = 32
+
+// NewKey generates a random 32-byte (256 bit) key.
+//
+// Panics if source of randomness fails.
+func NewKey() []byte {
+	return randomBytes(DefaultKeySize)
+}
+
+// NewBase64Key generates a random base64 encoded 32-byte key.
+//
+// Panics if source of randomness fails.
+func NewBase64Key() string {
+	return NewRandomStringN(DefaultKeySize)
+}
+
+// NewRandomStringN returns base64 encoded random string of a given num of bytes.
+//
+// Panics if source of randomness fails.
+func NewRandomStringN(c int) string {
+	return base64.StdEncoding.EncodeToString(randomBytes(c))
+}
+
+// randomBytes generates C number of random bytes suitable for cryptographic
+// operations.
+//
+// Panics if source of randomness fails.
+func randomBytes(c int) []byte {
+	if c < 0 {
+		c = DefaultKeySize
+	}
+	b := make([]byte, c)
+	if _, err := rand.Read(b); err != nil {
+		panic(err)
+	}
+	return b
+}
diff --git a/internal/cryptutil/helpers_test.go b/internal/cryptutil/helpers_test.go
new file mode 100644
index 000000000..6bc9797f3
--- /dev/null
+++ b/internal/cryptutil/helpers_test.go
@@ -0,0 +1,55 @@
+package cryptutil // import "github.com/pomerium/pomerium/internal/cryptutil"
+
+import (
+	"encoding/base64"
+	"testing"
+)
+
+func TestGenerateRandomString(t *testing.T) {
+	t.Parallel()
+	tests := []struct {
+		name string
+		c    int
+		want int
+	}{
+		{"simple", 32, 32},
+		{"zero", 0, 0},
+		{"negative", -1, 32},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			o := NewRandomStringN(tt.c)
+			b, err := base64.StdEncoding.DecodeString(o)
+			if err != nil {
+				t.Error(err)
+			}
+			got := len(b)
+			if got != tt.want {
+				t.Errorf("NewRandomStringN() = %d, want %d", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestNewBase64Key(t *testing.T) {
+	t.Parallel()
+	tests := []struct {
+		name string
+		want int
+	}{
+		{"simple", 32},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			o := NewBase64Key()
+			b, err := base64.StdEncoding.DecodeString(o)
+			if err != nil {
+				t.Error(err)
+			}
+			got := len(b)
+			if got != tt.want {
+				t.Errorf("NewBase64Key() = %d, want %d", got, tt.want)
+			}
+		})
+	}
+}
diff --git a/internal/cryptutil/hmac.go b/internal/cryptutil/hmac.go
new file mode 100644
index 000000000..c86472de8
--- /dev/null
+++ b/internal/cryptutil/hmac.go
@@ -0,0 +1,50 @@
+package cryptutil // import "github.com/pomerium/pomerium/internal/cryptutil"
+import (
+	"crypto/hmac"
+	"crypto/sha512"
+	"errors"
+	"strconv"
+	"time"
+)
+
+var (
+	errTimestampMalformed = errors.New("internal/cryptutil: timestamp malformed")
+	errTimestampExpired   = errors.New("internal/cryptutil: timestamp expired")
+	errTimestampTooSoon   = errors.New("internal/cryptutil: timestamp too soon")
+)
+
+// GenerateHMAC produces a symmetric signature using a shared secret key.
+func GenerateHMAC(data []byte, key string) []byte {
+	h := hmac.New(sha512.New512_256, []byte(key))
+	h.Write(data)
+	return h.Sum(nil)
+
+}
+
+// CheckHMAC securely checks the supplied MAC against a message using the
+// shared secret key.
+func CheckHMAC(data, suppliedMAC []byte, key string) bool {
+	expectedMAC := GenerateHMAC(data, key)
+	return hmac.Equal(expectedMAC, suppliedMAC)
+}
+
+// ValidTimestamp is a helper function often used in conjunction with an HMAC
+// function to verify that the timestamp (in unix seconds) is within leeway
+// period.
+// todo(bdd) : should leeway be configurable?
+func ValidTimestamp(ts string) error {
+	var timeStamp int64
+	var err error
+	if timeStamp, err = strconv.ParseInt(ts, 10, 64); err != nil {
+		return errTimestampMalformed
+	}
+	// unix time in seconds
+	tm := time.Unix(timeStamp, 0)
+	if time.Since(tm) > DefaultLeeway {
+		return errTimestampExpired
+	}
+	if time.Until(tm) > DefaultLeeway {
+		return errTimestampTooSoon
+	}
+	return nil
+}
diff --git a/internal/cryptutil/hmac_test.go b/internal/cryptutil/hmac_test.go
new file mode 100644
index 000000000..83e2539ee
--- /dev/null
+++ b/internal/cryptutil/hmac_test.go
@@ -0,0 +1,70 @@
+package cryptutil
+
+import (
+	"bytes"
+	"encoding/hex"
+	"fmt"
+	"testing"
+	"time"
+)
+
+func TestHMAC(t *testing.T) {
+	// https://groups.google.com/d/msg/sci.crypt/OolWgsgQD-8/jHciyWkaL0gJ
+	hmacTests := []struct {
+		key    string
+		data   string
+		digest string
+	}{
+		{
+			key:    "0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b",
+			data:   "4869205468657265", // "Hi There"
+			digest: "9f9126c3d9c3c330d760425ca8a217e31feae31bfe70196ff81642b868402eab",
+		},
+		{
+			key:    "4a656665",                                                 // "Jefe"
+			data:   "7768617420646f2079612077616e7420666f72206e6f7468696e673f", // "what do ya want for nothing?"
+			digest: "6df7b24630d5ccb2ee335407081a87188c221489768fa2020513b2d593359456",
+		},
+	}
+	for idx, tt := range hmacTests {
+		keySlice, _ := hex.DecodeString(tt.key)
+		dataBytes, _ := hex.DecodeString(tt.data)
+		expectedDigest, _ := hex.DecodeString(tt.digest)
+
+		keyBytes := &[32]byte{}
+		copy(keyBytes[:], keySlice)
+
+		macDigest := GenerateHMAC(dataBytes, string(keyBytes[:]))
+		if !bytes.Equal(macDigest, expectedDigest) {
+			t.Errorf("test %d generated unexpected mac", idx)
+		}
+		if !CheckHMAC(dataBytes, macDigest, string(keyBytes[:])) {
+			t.Errorf("test %d generated unexpected mac", idx)
+		}
+	}
+}
+
+func TestValidTimestamp(t *testing.T) {
+	t.Parallel()
+	tests := []struct {
+		name    string
+		ts      string
+		wantErr bool
+	}{
+		{"good - now", fmt.Sprint(time.Now().Unix()), false},
+		{"good - now - 200ms", fmt.Sprint(time.Now().Add(-200 * time.Millisecond).Unix()), false},
+		{"good - now + 200ms", fmt.Sprint(time.Now().Add(200 * time.Millisecond).Unix()), false},
+		{"bad - now + 10m", fmt.Sprint(time.Now().Add(10 * time.Minute).Unix()), true},
+		{"bad - now - 10m", fmt.Sprint(time.Now().Add(-10 * time.Minute).Unix()), true},
+		{"malformed - non int", fmt.Sprint("pomerium"), true},
+		{"malformed - negative number", fmt.Sprint("-1"), true},
+		{"malformed - huge number", fmt.Sprintf("%d", 10*10000000000), true},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if err := ValidTimestamp(tt.ts); (err != nil) != tt.wantErr {
+				t.Errorf("ValidTimestamp() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
diff --git a/internal/cryptutil/mock_cipher.go b/internal/cryptutil/mock_cipher.go
index 13e5dde88..4f7012ee0 100644
--- a/internal/cryptutil/mock_cipher.go
+++ b/internal/cryptutil/mock_cipher.go
@@ -1,28 +1,18 @@
 package cryptutil // import "github.com/pomerium/pomerium/internal/cryptutil"
 
-// MockCipher MockCSRFStore is a mock implementation of Cipher.
-type MockCipher struct {
-	EncryptResponse []byte
-	EncryptError    error
-	DecryptResponse []byte
-	DecryptError    error
+// MockEncoder MockCSRFStore is a mock implementation of Cipher.
+type MockEncoder struct {
 	MarshalResponse string
 	MarshalError    error
 	UnmarshalError  error
 }
 
-// Encrypt is a mock implementation of MockCipher.
-func (mc MockCipher) Encrypt(b []byte) ([]byte, error) { return mc.EncryptResponse, mc.EncryptError }
-
-// Decrypt is a mock implementation of MockCipher.
-func (mc MockCipher) Decrypt(b []byte) ([]byte, error) { return mc.DecryptResponse, mc.DecryptError }
-
-// Marshal is a mock implementation of MockCipher.
-func (mc MockCipher) Marshal(i interface{}) (string, error) {
+// Marshal is a mock implementation of MockEncoder.
+func (mc MockEncoder) Marshal(i interface{}) (string, error) {
 	return mc.MarshalResponse, mc.MarshalError
 }
 
-// Unmarshal is a mock implementation of MockCipher.
-func (mc MockCipher) Unmarshal(s string, i interface{}) error {
+// Unmarshal is a mock implementation of MockEncoder.
+func (mc MockEncoder) Unmarshal(s string, i interface{}) error {
 	return mc.UnmarshalError
 }
diff --git a/internal/cryptutil/mock_cipher_test.go b/internal/cryptutil/mock_cipher_test.go
index 037fc2dff..9665b71e8 100644
--- a/internal/cryptutil/mock_cipher_test.go
+++ b/internal/cryptutil/mock_cipher_test.go
@@ -5,31 +5,13 @@ import (
 	"testing"
 )
 
-func TestMockCipher_Unmarshal(t *testing.T) {
+func TestMockEncoder(t *testing.T) {
 	e := errors.New("err")
-	mc := MockCipher{
-		EncryptResponse: []byte("EncryptResponse"),
-		EncryptError:    e,
-		DecryptResponse: []byte("DecryptResponse"),
-		DecryptError:    e,
+	mc := MockEncoder{
 		MarshalResponse: "MarshalResponse",
 		MarshalError:    e,
 		UnmarshalError:  e,
 	}
-	b, err := mc.Encrypt([]byte("test"))
-	if string(b) != "EncryptResponse" {
-		t.Error("unexpected encrypt response")
-	}
-	if err != e {
-		t.Error("unexpected encrypt error")
-	}
-	b, err = mc.Decrypt([]byte("test"))
-	if string(b) != "DecryptResponse" {
-		t.Error("unexpected Decrypt response")
-	}
-	if err != e {
-		t.Error("unexpected Decrypt error")
-	}
 	s, err := mc.Marshal("test")
 	if err != e {
 		t.Error("unexpected Marshal error")
diff --git a/internal/cryptutil/sign.go b/internal/cryptutil/sign.go
index 657ad3aff..3aa9b7144 100644
--- a/internal/cryptutil/sign.go
+++ b/internal/cryptutil/sign.go
@@ -9,6 +9,11 @@ import (
 	"gopkg.in/square/go-jose.v2/jwt"
 )
 
+const (
+	// DefaultLeeway defines the default leeway for matching NotBefore/Expiry claims.
+	DefaultLeeway = 5.0 * time.Minute
+)
+
 // JWTSigner implements JWT signing according to JSON Web Token (JWT) RFC7519
 // https://tools.ietf.org/html/rfc7519
 type JWTSigner interface {
@@ -92,8 +97,8 @@ func (s *ES256Signer) SignJWT(user, email, groups string) (string, error) {
 	s.Groups = groups
 	now := time.Now()
 	s.IssuedAt = *jwt.NewNumericDate(now)
-	s.Expiry = *jwt.NewNumericDate(now.Add(jwt.DefaultLeeway))
-	s.NotBefore = *jwt.NewNumericDate(now.Add(-1 * jwt.DefaultLeeway))
+	s.Expiry = *jwt.NewNumericDate(now.Add(DefaultLeeway))
+	s.NotBefore = *jwt.NewNumericDate(now.Add(-1 * DefaultLeeway))
 	rawJWT, err := jwt.Signed(s.signer).Claims(s).CompactSerialize()
 	if err != nil {
 		return "", fmt.Errorf("cryptutil: sign failed %v", err)
diff --git a/internal/httputil/router_test.go b/internal/httputil/router_test.go
index 96fa0e4ef..42b82481c 100644
--- a/internal/httputil/router_test.go
+++ b/internal/httputil/router_test.go
@@ -1,11 +1,13 @@
-package httputil // import "github.com/pomerium/pomerium/internal/httputil"
+package httputil
 
 import (
 	"net/http"
 	"net/http/httptest"
+	"reflect"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
+	"github.com/gorilla/mux"
 )
 
 func TestCSRFFailureHandler(t *testing.T) {
@@ -35,3 +37,19 @@ func TestCSRFFailureHandler(t *testing.T) {
 		})
 	}
 }
+
+func TestNewRouter(t *testing.T) {
+	tests := []struct {
+		name string
+		want *mux.Router
+	}{
+		{"this is a gorilla router right?", mux.NewRouter()},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := NewRouter(); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("NewRouter() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
diff --git a/internal/middleware/middleware.go b/internal/middleware/middleware.go
index ce3f22511..80db0183f 100644
--- a/internal/middleware/middleware.go
+++ b/internal/middleware/middleware.go
@@ -1,14 +1,11 @@
 package middleware // import "github.com/pomerium/pomerium/internal/middleware"
 
 import (
-	"crypto/hmac"
 	"encoding/base64"
 	"fmt"
 	"net/http"
 	"net/url"
-	"strconv"
 	"strings"
-	"time"
 
 	"github.com/pomerium/pomerium/internal/cryptutil"
 	"github.com/pomerium/pomerium/internal/httputil"
@@ -183,22 +180,8 @@ func ValidSignature(redirectURI, sigVal, timestamp, secret string) bool {
 	if err != nil {
 		return false
 	}
-	i, err := strconv.ParseInt(timestamp, 10, 64)
-	if err != nil {
+	if err := cryptutil.ValidTimestamp(timestamp); err != nil {
 		return false
 	}
-	tm := time.Unix(i, 0)
-	ttl := 5 * time.Minute
-	if time.Since(tm) > ttl {
-		return false
-	}
-	localSig := redirectURLSignature(redirectURI, tm, secret)
-
-	return hmac.Equal(requestSig, localSig)
-}
-
-func redirectURLSignature(rawRedirect string, timestamp time.Time, secret string) []byte {
-	data := []byte(fmt.Sprint(rawRedirect, timestamp.Unix()))
-	h := cryptutil.Hash(secret, data)
-	return h
+	return cryptutil.CheckHMAC([]byte(fmt.Sprint(redirectURI, timestamp)), requestSig, secret)
 }
diff --git a/internal/middleware/middleware_test.go b/internal/middleware/middleware_test.go
index 000f768ca..3a5126489 100644
--- a/internal/middleware/middleware_test.go
+++ b/internal/middleware/middleware_test.go
@@ -8,8 +8,15 @@ import (
 	"net/url"
 	"testing"
 	"time"
+
+	"github.com/pomerium/pomerium/internal/cryptutil"
 )
 
+func hmacHelperFunc(rawRedirect string, timestamp time.Time, secret string) []byte {
+	data := []byte(fmt.Sprint(rawRedirect, timestamp.Unix()))
+	return cryptutil.GenerateHMAC(data, secret)
+}
+
 func Test_SameDomain(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
@@ -45,7 +52,7 @@ func Test_ValidSignature(t *testing.T) {
 	goodURL := "https://example.com/redirect"
 	secretA := "41aOD7VNtQ1/KZDCGrkYpaHwB50JC1y6BDs2KPRVd2A="
 	now := fmt.Sprint(time.Now().Unix())
-	rawSig := redirectURLSignature(goodURL, time.Now(), secretA)
+	rawSig := hmacHelperFunc(goodURL, time.Now(), secretA)
 	sig := base64.URLEncoding.EncodeToString(rawSig)
 	staleTime := fmt.Sprint(time.Now().Add(-6 * time.Minute).Unix())
 
@@ -73,27 +80,6 @@ func Test_ValidSignature(t *testing.T) {
 	}
 }
 
-func Test_redirectURLSignature(t *testing.T) {
-	tests := []struct {
-		name        string
-		rawRedirect string
-		timestamp   time.Time
-		secret      string
-		want        string
-	}{
-		{"good signature", "https://example.com/redirect", time.Unix(1546797901, 0), "K3yqsJPahIzu5CdfCVJlIK4N8Dc135-27Tg1ROuQdhc=", "XeVJC2Iysq7mRUwOL3FX_5vx1d_kZV2HONHNig9fcKk="},
-	}
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			got := redirectURLSignature(tt.rawRedirect, tt.timestamp, tt.secret)
-			out := base64.URLEncoding.EncodeToString(got)
-			if out != tt.want {
-				t.Errorf("redirectURLSignature() = %v, want %v", tt.want, out)
-			}
-		})
-	}
-}
-
 func TestSetHeaders(t *testing.T) {
 	tests := []struct {
 		name            string
@@ -209,7 +195,7 @@ func TestValidateSignature(t *testing.T) {
 	secretA := "41aOD7VNtQ1/KZDCGrkYpaHwB50JC1y6BDs2KPRVd2A="
 	now := fmt.Sprint(time.Now().Unix())
 	goodURL := "https://example.com/redirect"
-	rawSig := redirectURLSignature(goodURL, time.Now(), secretA)
+	rawSig := hmacHelperFunc(goodURL, time.Now(), secretA)
 	sig := base64.URLEncoding.EncodeToString(rawSig)
 	staleTime := fmt.Sprint(time.Now().Add(-6 * time.Minute).Unix())
 
diff --git a/internal/sessions/cookie_store.go b/internal/sessions/cookie_store.go
index 96f2a2846..5043f06c5 100644
--- a/internal/sessions/cookie_store.go
+++ b/internal/sessions/cookie_store.go
@@ -33,7 +33,7 @@ const MaxNumChunks = 5
 // CookieStore represents all the cookie related configurations
 type CookieStore struct {
 	Name              string
-	CookieCipher      cryptutil.Cipher
+	Encoder           cryptutil.SecureEncoder
 	CookieExpire      time.Duration
 	CookieRefresh     time.Duration
 	CookieSecure      bool
@@ -50,7 +50,7 @@ type CookieStoreOptions struct {
 	CookieDomain      string
 	BearerTokenHeader string
 	CookieExpire      time.Duration
-	CookieCipher      cryptutil.Cipher
+	Encoder           cryptutil.SecureEncoder
 }
 
 // NewCookieStore returns a new session with ciphers for each of the cookie secrets
@@ -58,7 +58,7 @@ func NewCookieStore(opts *CookieStoreOptions) (*CookieStore, error) {
 	if opts.Name == "" {
 		return nil, fmt.Errorf("internal/sessions: cookie name cannot be empty")
 	}
-	if opts.CookieCipher == nil {
+	if opts.Encoder == nil {
 		return nil, fmt.Errorf("internal/sessions: cipher cannot be nil")
 	}
 	if opts.BearerTokenHeader == "" {
@@ -71,7 +71,7 @@ func NewCookieStore(opts *CookieStoreOptions) (*CookieStore, error) {
 		CookieHTTPOnly:    opts.CookieHTTPOnly,
 		CookieDomain:      opts.CookieDomain,
 		CookieExpire:      opts.CookieExpire,
-		CookieCipher:      opts.CookieCipher,
+		Encoder:           opts.Encoder,
 		BearerTokenHeader: opts.BearerTokenHeader,
 	}, nil
 }
@@ -188,7 +188,7 @@ func (cs *CookieStore) LoadSession(req *http.Request) (*State, error) {
 	if cipherText == "" {
 		return nil, ErrEmptySession
 	}
-	session, err := UnmarshalSession(cipherText, cs.CookieCipher)
+	session, err := UnmarshalSession(cipherText, cs.Encoder)
 	if err != nil {
 		return nil, err
 	}
@@ -197,7 +197,7 @@ func (cs *CookieStore) LoadSession(req *http.Request) (*State, error) {
 
 // SaveSession saves a session state to a request sessions.
 func (cs *CookieStore) SaveSession(w http.ResponseWriter, req *http.Request, s *State) error {
-	value, err := MarshalSession(s, cs.CookieCipher)
+	value, err := MarshalSession(s, cs.Encoder)
 	if err != nil {
 		return err
 	}
diff --git a/internal/sessions/cookie_store_test.go b/internal/sessions/cookie_store_test.go
index 58c0a9f10..cd70fe779 100644
--- a/internal/sessions/cookie_store_test.go
+++ b/internal/sessions/cookie_store_test.go
@@ -15,33 +15,21 @@ import (
 	"github.com/pomerium/pomerium/internal/cryptutil"
 )
 
-type mockCipher struct{}
+type MockEncoder struct{}
 
-func (a mockCipher) Encrypt(s []byte) ([]byte, error) {
-	if string(s) == "error" {
-		return []byte(""), errors.New("error encrypting")
-	}
-	return []byte("OK"), nil
-}
-
-func (a mockCipher) Decrypt(s []byte) ([]byte, error) {
-	if string(s) == "error" {
-		return []byte(""), errors.New("error encrypting")
-	}
-	return []byte("OK"), nil
-}
-func (a mockCipher) Marshal(s interface{}) (string, error) { return "", errors.New("error") }
-func (a mockCipher) Unmarshal(s string, i interface{}) error {
+func (a MockEncoder) Marshal(s interface{}) (string, error) { return "", errors.New("error") }
+func (a MockEncoder) Unmarshal(s string, i interface{}) error {
 	if s == "unmarshal error" || s == "error" {
 		return errors.New("error")
 	}
 	return nil
 }
 func TestNewCookieStore(t *testing.T) {
-	cipher, err := cryptutil.NewCipher(cryptutil.NewKey())
+	cipher, err := cryptutil.NewAEADCipher(cryptutil.NewKey())
 	if err != nil {
 		t.Fatal(err)
 	}
+	encoder := cryptutil.NewSecureJSONEncoder(cipher)
 	tests := []struct {
 		name    string
 		opts    *CookieStoreOptions
@@ -55,7 +43,7 @@ func TestNewCookieStore(t *testing.T) {
 				CookieHTTPOnly:    true,
 				CookieDomain:      "pomerium.io",
 				CookieExpire:      10 * time.Second,
-				CookieCipher:      cipher,
+				Encoder:           encoder,
 				BearerTokenHeader: "Authorization",
 			},
 			&CookieStore{
@@ -64,7 +52,7 @@ func TestNewCookieStore(t *testing.T) {
 				CookieHTTPOnly:    true,
 				CookieDomain:      "pomerium.io",
 				CookieExpire:      10 * time.Second,
-				CookieCipher:      cipher,
+				Encoder:           encoder,
 				BearerTokenHeader: "Authorization",
 			},
 			false},
@@ -75,7 +63,7 @@ func TestNewCookieStore(t *testing.T) {
 				CookieHTTPOnly:    true,
 				CookieDomain:      "pomerium.io",
 				CookieExpire:      10 * time.Second,
-				CookieCipher:      cipher,
+				Encoder:           encoder,
 				BearerTokenHeader: "Authorization",
 			},
 			nil,
@@ -87,7 +75,7 @@ func TestNewCookieStore(t *testing.T) {
 				CookieHTTPOnly: true,
 				CookieDomain:   "pomerium.io",
 				CookieExpire:   10 * time.Second,
-				CookieCipher:   nil,
+				Encoder:        nil,
 			},
 			nil,
 			true},
@@ -100,7 +88,7 @@ func TestNewCookieStore(t *testing.T) {
 				return
 			}
 			cmpOpts := []cmp.Option{
-				cmpopts.IgnoreUnexported(cryptutil.XChaCha20Cipher{}),
+				cmpopts.IgnoreUnexported(cryptutil.SecureJSONEncoder{}),
 			}
 
 			if diff := cmp.Diff(got, tt.want, cmpOpts...); diff != "" {
@@ -111,7 +99,8 @@ func TestNewCookieStore(t *testing.T) {
 }
 
 func TestCookieStore_makeCookie(t *testing.T) {
-	cipher, err := cryptutil.NewCipher(cryptutil.NewKey())
+	cipher, err := cryptutil.NewAEADCipher(cryptutil.NewKey())
+
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -145,7 +134,7 @@ func TestCookieStore_makeCookie(t *testing.T) {
 					CookieHTTPOnly: true,
 					CookieDomain:   tt.cookieDomain,
 					CookieExpire:   10 * time.Second,
-					CookieCipher:   cipher})
+					Encoder:        cryptutil.NewSecureJSONEncoder(cipher)})
 			if err != nil {
 				t.Fatal(err)
 			}
@@ -161,10 +150,12 @@ func TestCookieStore_makeCookie(t *testing.T) {
 }
 
 func TestCookieStore_SaveSession(t *testing.T) {
-	cipher, err := cryptutil.NewCipher(cryptutil.NewKey())
+	c, err := cryptutil.NewAEADCipher(cryptutil.NewKey())
 	if err != nil {
 		t.Fatal(err)
 	}
+	cipher := cryptutil.NewSecureJSONEncoder(c)
+
 	hugeString := make([]byte, 4097)
 	if _, err := rand.Read(hugeString); err != nil {
 		t.Fatal(err)
@@ -172,12 +163,12 @@ func TestCookieStore_SaveSession(t *testing.T) {
 	tests := []struct {
 		name        string
 		State       *State
-		cipher      cryptutil.Cipher
+		cipher      cryptutil.SecureEncoder
 		wantErr     bool
 		wantLoadErr bool
 	}{
 		{"good", &State{AccessToken: "token1234", RefreshToken: "refresh4321", RefreshDeadline: time.Now().Add(1 * time.Hour).Truncate(time.Second).UTC(), Email: "user@domain.com", User: "user"}, cipher, false, false},
-		{"bad cipher", &State{AccessToken: "token1234", RefreshToken: "refresh4321", RefreshDeadline: time.Now().Add(1 * time.Hour).Truncate(time.Second).UTC(), Email: "user@domain.com", User: "user"}, mockCipher{}, true, true},
+		{"bad cipher", &State{AccessToken: "token1234", RefreshToken: "refresh4321", RefreshDeadline: time.Now().Add(1 * time.Hour).Truncate(time.Second).UTC(), Email: "user@domain.com", User: "user"}, MockEncoder{}, true, true},
 		{"huge cookie", &State{AccessToken: fmt.Sprintf("%x", hugeString), RefreshToken: "refresh4321", RefreshDeadline: time.Now().Add(1 * time.Hour).Truncate(time.Second).UTC(), Email: "user@domain.com", User: "user"}, cipher, false, false},
 	}
 	for _, tt := range tests {
@@ -188,7 +179,7 @@ func TestCookieStore_SaveSession(t *testing.T) {
 				CookieHTTPOnly: true,
 				CookieDomain:   "pomerium.io",
 				CookieExpire:   10 * time.Second,
-				CookieCipher:   tt.cipher}
+				Encoder:        tt.cipher}
 
 			r := httptest.NewRequest("GET", "/", nil)
 			w := httptest.NewRecorder()
diff --git a/internal/sessions/middleware_test.go b/internal/sessions/middleware_test.go
index 40be51824..74f6eb3f7 100644
--- a/internal/sessions/middleware_test.go
+++ b/internal/sessions/middleware_test.go
@@ -81,11 +81,13 @@ func TestVerifier(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			cipher, err := cryptutil.NewCipherFromBase64(cryptutil.NewBase64Key())
+			cipher, err := cryptutil.NewAEADCipherFromBase64(cryptutil.NewBase64Key())
+			encoder := cryptutil.NewSecureJSONEncoder(cipher)
+
 			if err != nil {
 				t.Fatal(err)
 			}
-			encSession, err := MarshalSession(&tt.state, cipher)
+			encSession, err := MarshalSession(&tt.state, encoder)
 			if err != nil {
 				t.Fatal(err)
 			}
@@ -96,8 +98,8 @@ func TestVerifier(t *testing.T) {
 			}
 
 			cs, err := NewCookieStore(&CookieStoreOptions{
-				Name:         "_pomerium",
-				CookieCipher: cipher,
+				Name:    "_pomerium",
+				Encoder: encoder,
 			})
 			if err != nil {
 				t.Fatal(err)
diff --git a/internal/sessions/state.go b/internal/sessions/state.go
index 59df7e4e2..79bb5a71f 100644
--- a/internal/sessions/state.go
+++ b/internal/sessions/state.go
@@ -89,7 +89,7 @@ func (s *State) IssuedAt() (time.Time, error) {
 
 // MarshalSession marshals the session state as JSON, encrypts the JSON using the
 // given cipher, and base64-encodes the result
-func MarshalSession(s *State, c cryptutil.Cipher) (string, error) {
+func MarshalSession(s *State, c cryptutil.SecureEncoder) (string, error) {
 	v, err := c.Marshal(s)
 	if err != nil {
 		return "", err
@@ -99,7 +99,7 @@ func MarshalSession(s *State, c cryptutil.Cipher) (string, error) {
 
 // UnmarshalSession takes the marshaled string, base64-decodes into a byte slice, decrypts the
 // byte slice using the passed cipher, and unmarshals the resulting JSON into a session state struct
-func UnmarshalSession(value string, c cryptutil.Cipher) (*State, error) {
+func UnmarshalSession(value string, c cryptutil.SecureEncoder) (*State, error) {
 	s := &State{}
 	err := c.Unmarshal(value, s)
 	if err != nil {
diff --git a/internal/sessions/state_test.go b/internal/sessions/state_test.go
index b92e09c95..c249136ff 100644
--- a/internal/sessions/state_test.go
+++ b/internal/sessions/state_test.go
@@ -13,7 +13,8 @@ import (
 
 func TestStateSerialization(t *testing.T) {
 	secret := cryptutil.NewKey()
-	c, err := cryptutil.NewCipher(secret)
+	cipher, err := cryptutil.NewAEADCipher(secret)
+	c := cryptutil.NewSecureJSONEncoder(cipher)
 	if err != nil {
 		t.Fatalf("expected to be able to create cipher: %v", err)
 	}
@@ -124,10 +125,12 @@ func TestState_Impersonating(t *testing.T) {
 
 func TestMarshalSession(t *testing.T) {
 	secret := cryptutil.NewKey()
-	c, err := cryptutil.NewCipher(secret)
+	cipher, err := cryptutil.NewAEADCipher(secret)
 	if err != nil {
 		t.Fatalf("expected to be able to create cipher: %v", err)
 	}
+	c := cryptutil.NewSecureJSONEncoder(cipher)
+
 	hugeString := make([]byte, 4097)
 	if _, err := rand.Read(hugeString); err != nil {
 		t.Fatal(err)
diff --git a/internal/urlutil/url.go b/internal/urlutil/url.go
index 571b43637..8920dbe19 100644
--- a/internal/urlutil/url.go
+++ b/internal/urlutil/url.go
@@ -81,9 +81,9 @@ func timestamp() int64 {
 
 // SignedRedirectURL takes a destination URL and adds redirect_uri to it's
 // query params, along with a timestamp and an keyed signature.
-func SignedRedirectURL(key string, destination, urlToSign *url.URL) *url.URL {
+func SignedRedirectURL(key string, destination, u *url.URL) *url.URL {
 	now := timestamp()
-	rawURL := urlToSign.String()
+	rawURL := u.String()
 	params, _ := url.ParseQuery(destination.RawQuery) // handled by incoming mux
 	params.Set("redirect_uri", rawURL)
 	params.Set("ts", fmt.Sprint(now))
@@ -95,7 +95,7 @@ func SignedRedirectURL(key string, destination, urlToSign *url.URL) *url.URL {
 // hmacURL takes a redirect url string and timestamp and returns the base64
 // encoded HMAC result.
 func hmacURL(key, data string, timestamp int64) string {
-	h := cryptutil.Hash(key, []byte(fmt.Sprint(data, timestamp)))
+	h := cryptutil.GenerateHMAC([]byte(fmt.Sprint(data, timestamp)), key)
 	return base64.URLEncoding.EncodeToString(h)
 }
 
diff --git a/proxy/handlers_test.go b/proxy/handlers_test.go
index 8d59b8cbc..d74971574 100644
--- a/proxy/handlers_test.go
+++ b/proxy/handlers_test.go
@@ -123,7 +123,7 @@ func TestProxy_router(t *testing.T) {
 			if err != nil {
 				t.Fatal(err)
 			}
-			p.cipher = &cryptutil.MockCipher{MarshalResponse: "foo"}
+			p.encoder = &cryptutil.MockEncoder{MarshalResponse: "foo"}
 
 			req := httptest.NewRequest(http.MethodGet, tt.host, nil)
 			_, ok := p.router(req)
@@ -203,7 +203,7 @@ func TestProxy_Proxy(t *testing.T) {
 			if err != nil {
 				t.Fatal(err)
 			}
-			p.cipher = &cryptutil.MockCipher{MarshalResponse: "foo"}
+			p.encoder = &cryptutil.MockEncoder{MarshalResponse: "foo"}
 			p.sessionStore = tt.session
 			p.AuthorizeClient = tt.authorizer
 			r := httptest.NewRequest(tt.method, tt.host, nil)
@@ -231,17 +231,17 @@ func TestProxy_UserDashboard(t *testing.T) {
 		ctxError   error
 		options    config.Options
 		method     string
-		cipher     cryptutil.Cipher
+		cipher     cryptutil.SecureEncoder
 		session    sessions.SessionStore
 		authorizer clients.Authorizer
 
 		wantAdminForm bool
 		wantStatus    int
 	}{
-		{"good", nil, opts, http.MethodGet, &cryptutil.MockCipher{}, &sessions.MockSessionStore{Session: &sessions.State{Email: "user@test.example", RefreshDeadline: time.Now().Add(10 * time.Second)}}, clients.MockAuthorize{}, false, http.StatusOK},
-		{"session context error", errors.New("error"), opts, http.MethodGet, &cryptutil.MockCipher{}, &sessions.MockSessionStore{Session: &sessions.State{Email: "user@test.example", RefreshDeadline: time.Now().Add(10 * time.Second)}}, clients.MockAuthorize{}, false, http.StatusInternalServerError},
-		{"want admin form good admin authorization", nil, opts, http.MethodGet, &cryptutil.MockCipher{}, &sessions.MockSessionStore{Session: &sessions.State{Email: "user@test.example", RefreshDeadline: time.Now().Add(10 * time.Second)}}, clients.MockAuthorize{IsAdminResponse: true}, true, http.StatusOK},
-		{"is admin but authorization fails", nil, opts, http.MethodGet, &cryptutil.MockCipher{}, &sessions.MockSessionStore{Session: &sessions.State{Email: "user@test.example", RefreshDeadline: time.Now().Add(10 * time.Second)}}, clients.MockAuthorize{IsAdminError: errors.New("err")}, false, http.StatusInternalServerError},
+		{"good", nil, opts, http.MethodGet, &cryptutil.MockEncoder{}, &sessions.MockSessionStore{Session: &sessions.State{Email: "user@test.example", RefreshDeadline: time.Now().Add(10 * time.Second)}}, clients.MockAuthorize{}, false, http.StatusOK},
+		{"session context error", errors.New("error"), opts, http.MethodGet, &cryptutil.MockEncoder{}, &sessions.MockSessionStore{Session: &sessions.State{Email: "user@test.example", RefreshDeadline: time.Now().Add(10 * time.Second)}}, clients.MockAuthorize{}, false, http.StatusInternalServerError},
+		{"want admin form good admin authorization", nil, opts, http.MethodGet, &cryptutil.MockEncoder{}, &sessions.MockSessionStore{Session: &sessions.State{Email: "user@test.example", RefreshDeadline: time.Now().Add(10 * time.Second)}}, clients.MockAuthorize{IsAdminResponse: true}, true, http.StatusOK},
+		{"is admin but authorization fails", nil, opts, http.MethodGet, &cryptutil.MockEncoder{}, &sessions.MockSessionStore{Session: &sessions.State{Email: "user@test.example", RefreshDeadline: time.Now().Add(10 * time.Second)}}, clients.MockAuthorize{IsAdminError: errors.New("err")}, false, http.StatusInternalServerError},
 	}
 
 	for _, tt := range tests {
@@ -250,7 +250,7 @@ func TestProxy_UserDashboard(t *testing.T) {
 			if err != nil {
 				t.Fatal(err)
 			}
-			p.cipher = tt.cipher
+			p.encoder = tt.cipher
 			p.sessionStore = tt.session
 			p.AuthorizeClient = tt.authorizer
 
@@ -289,17 +289,17 @@ func TestProxy_ForceRefresh(t *testing.T) {
 		ctxError   error
 		options    config.Options
 		method     string
-		cipher     cryptutil.Cipher
+		cipher     cryptutil.SecureEncoder
 		session    sessions.SessionStore
 		authorizer clients.Authorizer
 		wantStatus int
 	}{
-		{"good", nil, opts, http.MethodGet, &cryptutil.MockCipher{}, &sessions.MockSessionStore{Session: &sessions.State{Email: "user@test.example", IDToken: "eyJhbGciOiJSUzI1NiIsImtpZCI6IjA3YTA4MjgzOWYyZTcxYTliZjZjNTk2OTk2Yjk0NzM5Nzg1YWZkYzMiLCJ0eXAiOiJKV1QifQ.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.Flah31XfqmPhWYh2rJ-6rtowmSQFgp6HqDf1rpS38Wo0DXnIYmXxEQVLanDNV62Z0sLhUk1QO9NqoSgA3NscM-Ww-JsqU80oKnWcMYweUb_KU0kfHyTiUB0iEHMqu6tXn5dA_dIaPnL5oorXZ_gG4sooRxBZrDkaNAjRINLciKDQkUTVaNfnM6IBZ_pWDPd2lWGtj8h8sEIe2PIiH73Z2VLlXz8kw60VTPsi9U2zrF0ZJ9MfRGJhceQ58vW2ZlFfXJixgvbOZjKmcRv8NaJDIUss48l0Bsya6icZ0l1ZK-sAiFr0KVLTl2ywu8d5SQpTJ1X7vDW_u_04xaqDQUdYKA"}}, clients.MockAuthorize{}, http.StatusFound},
-		{"cannot load session", errors.New("error"), opts, http.MethodGet, &cryptutil.MockCipher{}, &sessions.MockSessionStore{Session: &sessions.State{Email: "user@test.example", IDToken: "eyJhbGciOiJSUzI1NiIsImtpZCI6IjA3YTA4MjgzOWYyZTcxYTliZjZjNTk2OTk2Yjk0NzM5Nzg1YWZkYzMiLCJ0eXAiOiJKV1QifQ.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.Flah31XfqmPhWYh2rJ-6rtowmSQFgp6HqDf1rpS38Wo0DXnIYmXxEQVLanDNV62Z0sLhUk1QO9NqoSgA3NscM-Ww-JsqU80oKnWcMYweUb_KU0kfHyTiUB0iEHMqu6tXn5dA_dIaPnL5oorXZ_gG4sooRxBZrDkaNAjRINLciKDQkUTVaNfnM6IBZ_pWDPd2lWGtj8h8sEIe2PIiH73Z2VLlXz8kw60VTPsi9U2zrF0ZJ9MfRGJhceQ58vW2ZlFfXJixgvbOZjKmcRv8NaJDIUss48l0Bsya6icZ0l1ZK-sAiFr0KVLTl2ywu8d5SQpTJ1X7vDW_u_04xaqDQUdYKA"}}, clients.MockAuthorize{}, http.StatusInternalServerError},
-		{"bad id token", nil, opts, http.MethodGet, &cryptutil.MockCipher{}, &sessions.MockSessionStore{Session: &sessions.State{RefreshDeadline: time.Now().Add(10 * time.Second), Email: "user@test.example", IDToken: "bad"}}, clients.MockAuthorize{}, http.StatusInternalServerError},
-		{"issue date too soon", nil, timeSinceError, http.MethodGet, &cryptutil.MockCipher{}, &sessions.MockSessionStore{Session: &sessions.State{RefreshDeadline: time.Now().Add(10 * time.Second), Email: "user@test.example", IDToken: "eyJhbGciOiJSUzI1NiIsImtpZCI6IjA3YTA4MjgzOWYyZTcxYTliZjZjNTk2OTk2Yjk0NzM5Nzg1YWZkYzMiLCJ0eXAiOiJKV1QifQ.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.Flah31XfqmPhWYh2rJ-6rtowmSQFgp6HqDf1rpS38Wo0DXnIYmXxEQVLanDNV62Z0sLhUk1QO9NqoSgA3NscM-Ww-JsqU80oKnWcMYweUb_KU0kfHyTiUB0iEHMqu6tXn5dA_dIaPnL5oorXZ_gG4sooRxBZrDkaNAjRINLciKDQkUTVaNfnM6IBZ_pWDPd2lWGtj8h8sEIe2PIiH73Z2VLlXz8kw60VTPsi9U2zrF0ZJ9MfRGJhceQ58vW2ZlFfXJixgvbOZjKmcRv8NaJDIUss48l0Bsya6icZ0l1ZK-sAiFr0KVLTl2ywu8d5SQpTJ1X7vDW_u_04xaqDQUdYKA"}}, clients.MockAuthorize{}, http.StatusBadRequest},
-		{"refresh failure", nil, opts, http.MethodGet, &cryptutil.MockCipher{}, &sessions.MockSessionStore{Session: &sessions.State{Email: "user@test.example", IDToken: "eyJhbGciOiJSUzI1NiIsImtpZCI6IjA3YTA4MjgzOWYyZTcxYTliZjZjNTk2OTk2Yjk0NzM5Nzg1YWZkYzMiLCJ0eXAiOiJKV1QifQ.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.Flah31XfqmPhWYh2rJ-6rtowmSQFgp6HqDf1rpS38Wo0DXnIYmXxEQVLanDNV62Z0sLhUk1QO9NqoSgA3NscM-Ww-JsqU80oKnWcMYweUb_KU0kfHyTiUB0iEHMqu6tXn5dA_dIaPnL5oorXZ_gG4sooRxBZrDkaNAjRINLciKDQkUTVaNfnM6IBZ_pWDPd2lWGtj8h8sEIe2PIiH73Z2VLlXz8kw60VTPsi9U2zrF0ZJ9MfRGJhceQ58vW2ZlFfXJixgvbOZjKmcRv8NaJDIUss48l0Bsya6icZ0l1ZK-sAiFr0KVLTl2ywu8d5SQpTJ1X7vDW_u_04xaqDQUdYKA"}}, clients.MockAuthorize{}, http.StatusFound},
-		{"can't save refreshed session", nil, opts, http.MethodGet, &cryptutil.MockCipher{}, &sessions.MockSessionStore{SaveError: errors.New("err"), Session: &sessions.State{Email: "user@test.example", IDToken: "eyJhbGciOiJSUzI1NiIsImtpZCI6IjA3YTA4MjgzOWYyZTcxYTliZjZjNTk2OTk2Yjk0NzM5Nzg1YWZkYzMiLCJ0eXAiOiJKV1QifQ.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.Flah31XfqmPhWYh2rJ-6rtowmSQFgp6HqDf1rpS38Wo0DXnIYmXxEQVLanDNV62Z0sLhUk1QO9NqoSgA3NscM-Ww-JsqU80oKnWcMYweUb_KU0kfHyTiUB0iEHMqu6tXn5dA_dIaPnL5oorXZ_gG4sooRxBZrDkaNAjRINLciKDQkUTVaNfnM6IBZ_pWDPd2lWGtj8h8sEIe2PIiH73Z2VLlXz8kw60VTPsi9U2zrF0ZJ9MfRGJhceQ58vW2ZlFfXJixgvbOZjKmcRv8NaJDIUss48l0Bsya6icZ0l1ZK-sAiFr0KVLTl2ywu8d5SQpTJ1X7vDW_u_04xaqDQUdYKA"}}, clients.MockAuthorize{}, http.StatusInternalServerError},
+		{"good", nil, opts, http.MethodGet, &cryptutil.MockEncoder{}, &sessions.MockSessionStore{Session: &sessions.State{Email: "user@test.example", IDToken: "eyJhbGciOiJSUzI1NiIsImtpZCI6IjA3YTA4MjgzOWYyZTcxYTliZjZjNTk2OTk2Yjk0NzM5Nzg1YWZkYzMiLCJ0eXAiOiJKV1QifQ.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.Flah31XfqmPhWYh2rJ-6rtowmSQFgp6HqDf1rpS38Wo0DXnIYmXxEQVLanDNV62Z0sLhUk1QO9NqoSgA3NscM-Ww-JsqU80oKnWcMYweUb_KU0kfHyTiUB0iEHMqu6tXn5dA_dIaPnL5oorXZ_gG4sooRxBZrDkaNAjRINLciKDQkUTVaNfnM6IBZ_pWDPd2lWGtj8h8sEIe2PIiH73Z2VLlXz8kw60VTPsi9U2zrF0ZJ9MfRGJhceQ58vW2ZlFfXJixgvbOZjKmcRv8NaJDIUss48l0Bsya6icZ0l1ZK-sAiFr0KVLTl2ywu8d5SQpTJ1X7vDW_u_04xaqDQUdYKA"}}, clients.MockAuthorize{}, http.StatusFound},
+		{"cannot load session", errors.New("error"), opts, http.MethodGet, &cryptutil.MockEncoder{}, &sessions.MockSessionStore{Session: &sessions.State{Email: "user@test.example", IDToken: "eyJhbGciOiJSUzI1NiIsImtpZCI6IjA3YTA4MjgzOWYyZTcxYTliZjZjNTk2OTk2Yjk0NzM5Nzg1YWZkYzMiLCJ0eXAiOiJKV1QifQ.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.Flah31XfqmPhWYh2rJ-6rtowmSQFgp6HqDf1rpS38Wo0DXnIYmXxEQVLanDNV62Z0sLhUk1QO9NqoSgA3NscM-Ww-JsqU80oKnWcMYweUb_KU0kfHyTiUB0iEHMqu6tXn5dA_dIaPnL5oorXZ_gG4sooRxBZrDkaNAjRINLciKDQkUTVaNfnM6IBZ_pWDPd2lWGtj8h8sEIe2PIiH73Z2VLlXz8kw60VTPsi9U2zrF0ZJ9MfRGJhceQ58vW2ZlFfXJixgvbOZjKmcRv8NaJDIUss48l0Bsya6icZ0l1ZK-sAiFr0KVLTl2ywu8d5SQpTJ1X7vDW_u_04xaqDQUdYKA"}}, clients.MockAuthorize{}, http.StatusInternalServerError},
+		{"bad id token", nil, opts, http.MethodGet, &cryptutil.MockEncoder{}, &sessions.MockSessionStore{Session: &sessions.State{RefreshDeadline: time.Now().Add(10 * time.Second), Email: "user@test.example", IDToken: "bad"}}, clients.MockAuthorize{}, http.StatusInternalServerError},
+		{"issue date too soon", nil, timeSinceError, http.MethodGet, &cryptutil.MockEncoder{}, &sessions.MockSessionStore{Session: &sessions.State{RefreshDeadline: time.Now().Add(10 * time.Second), Email: "user@test.example", IDToken: "eyJhbGciOiJSUzI1NiIsImtpZCI6IjA3YTA4MjgzOWYyZTcxYTliZjZjNTk2OTk2Yjk0NzM5Nzg1YWZkYzMiLCJ0eXAiOiJKV1QifQ.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.Flah31XfqmPhWYh2rJ-6rtowmSQFgp6HqDf1rpS38Wo0DXnIYmXxEQVLanDNV62Z0sLhUk1QO9NqoSgA3NscM-Ww-JsqU80oKnWcMYweUb_KU0kfHyTiUB0iEHMqu6tXn5dA_dIaPnL5oorXZ_gG4sooRxBZrDkaNAjRINLciKDQkUTVaNfnM6IBZ_pWDPd2lWGtj8h8sEIe2PIiH73Z2VLlXz8kw60VTPsi9U2zrF0ZJ9MfRGJhceQ58vW2ZlFfXJixgvbOZjKmcRv8NaJDIUss48l0Bsya6icZ0l1ZK-sAiFr0KVLTl2ywu8d5SQpTJ1X7vDW_u_04xaqDQUdYKA"}}, clients.MockAuthorize{}, http.StatusBadRequest},
+		{"refresh failure", nil, opts, http.MethodGet, &cryptutil.MockEncoder{}, &sessions.MockSessionStore{Session: &sessions.State{Email: "user@test.example", IDToken: "eyJhbGciOiJSUzI1NiIsImtpZCI6IjA3YTA4MjgzOWYyZTcxYTliZjZjNTk2OTk2Yjk0NzM5Nzg1YWZkYzMiLCJ0eXAiOiJKV1QifQ.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.Flah31XfqmPhWYh2rJ-6rtowmSQFgp6HqDf1rpS38Wo0DXnIYmXxEQVLanDNV62Z0sLhUk1QO9NqoSgA3NscM-Ww-JsqU80oKnWcMYweUb_KU0kfHyTiUB0iEHMqu6tXn5dA_dIaPnL5oorXZ_gG4sooRxBZrDkaNAjRINLciKDQkUTVaNfnM6IBZ_pWDPd2lWGtj8h8sEIe2PIiH73Z2VLlXz8kw60VTPsi9U2zrF0ZJ9MfRGJhceQ58vW2ZlFfXJixgvbOZjKmcRv8NaJDIUss48l0Bsya6icZ0l1ZK-sAiFr0KVLTl2ywu8d5SQpTJ1X7vDW_u_04xaqDQUdYKA"}}, clients.MockAuthorize{}, http.StatusFound},
+		{"can't save refreshed session", nil, opts, http.MethodGet, &cryptutil.MockEncoder{}, &sessions.MockSessionStore{SaveError: errors.New("err"), Session: &sessions.State{Email: "user@test.example", IDToken: "eyJhbGciOiJSUzI1NiIsImtpZCI6IjA3YTA4MjgzOWYyZTcxYTliZjZjNTk2OTk2Yjk0NzM5Nzg1YWZkYzMiLCJ0eXAiOiJKV1QifQ.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.Flah31XfqmPhWYh2rJ-6rtowmSQFgp6HqDf1rpS38Wo0DXnIYmXxEQVLanDNV62Z0sLhUk1QO9NqoSgA3NscM-Ww-JsqU80oKnWcMYweUb_KU0kfHyTiUB0iEHMqu6tXn5dA_dIaPnL5oorXZ_gG4sooRxBZrDkaNAjRINLciKDQkUTVaNfnM6IBZ_pWDPd2lWGtj8h8sEIe2PIiH73Z2VLlXz8kw60VTPsi9U2zrF0ZJ9MfRGJhceQ58vW2ZlFfXJixgvbOZjKmcRv8NaJDIUss48l0Bsya6icZ0l1ZK-sAiFr0KVLTl2ywu8d5SQpTJ1X7vDW_u_04xaqDQUdYKA"}}, clients.MockAuthorize{}, http.StatusInternalServerError},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -307,7 +307,7 @@ func TestProxy_ForceRefresh(t *testing.T) {
 			if err != nil {
 				t.Fatal(err)
 			}
-			p.cipher = tt.cipher
+			p.encoder = tt.cipher
 			p.sessionStore = tt.session
 			p.AuthorizeClient = tt.authorizer
 
@@ -340,18 +340,18 @@ func TestProxy_Impersonate(t *testing.T) {
 		email        string
 		groups       string
 		csrf         string
-		cipher       cryptutil.Cipher
+		cipher       cryptutil.SecureEncoder
 		sessionStore sessions.SessionStore
 		authorizer   clients.Authorizer
 		wantStatus   int
 	}{
-		{"good", false, opts, nil, http.MethodPost, "user@blah.com", "", "", &cryptutil.MockCipher{}, &sessions.MockSessionStore{Session: &sessions.State{Email: "user@test.example", IDToken: ""}}, clients.MockAuthorize{IsAdminResponse: true}, http.StatusFound},
-		{"good", false, opts, errors.New("error"), http.MethodPost, "user@blah.com", "", "", &cryptutil.MockCipher{}, &sessions.MockSessionStore{Session: &sessions.State{Email: "user@test.example", IDToken: ""}}, clients.MockAuthorize{IsAdminResponse: true}, http.StatusInternalServerError},
-		{"session load error", false, opts, nil, http.MethodPost, "user@blah.com", "", "", &cryptutil.MockCipher{}, &sessions.MockSessionStore{LoadError: errors.New("err"), Session: &sessions.State{Email: "user@test.example", IDToken: ""}}, clients.MockAuthorize{IsAdminResponse: true}, http.StatusFound},
-		{"non admin users rejected", false, opts, nil, http.MethodPost, "user@blah.com", "", "", &cryptutil.MockCipher{}, &sessions.MockSessionStore{Session: &sessions.State{RefreshDeadline: time.Now().Add(10 * time.Second), Email: "user@test.example", IDToken: ""}}, clients.MockAuthorize{IsAdminResponse: false}, http.StatusForbidden},
-		{"non admin users rejected on error", false, opts, nil, http.MethodPost, "user@blah.com", "", "", &cryptutil.MockCipher{}, &sessions.MockSessionStore{Session: &sessions.State{RefreshDeadline: time.Now().Add(10 * time.Second), Email: "user@test.example", IDToken: ""}}, clients.MockAuthorize{IsAdminResponse: true, IsAdminError: errors.New("err")}, http.StatusForbidden},
-		{"save session failure", false, opts, nil, http.MethodPost, "user@blah.com", "", "", &cryptutil.MockCipher{}, &sessions.MockSessionStore{SaveError: errors.New("err"), Session: &sessions.State{RefreshDeadline: time.Now().Add(10 * time.Second), Email: "user@test.example", IDToken: ""}}, clients.MockAuthorize{IsAdminResponse: true}, http.StatusInternalServerError},
-		{"groups", false, opts, nil, http.MethodPost, "user@blah.com", "group1,group2", "", &cryptutil.MockCipher{}, &sessions.MockSessionStore{Session: &sessions.State{RefreshDeadline: time.Now().Add(10 * time.Second), Email: "user@test.example", IDToken: ""}}, clients.MockAuthorize{IsAdminResponse: true}, http.StatusFound},
+		{"good", false, opts, nil, http.MethodPost, "user@blah.com", "", "", &cryptutil.MockEncoder{}, &sessions.MockSessionStore{Session: &sessions.State{Email: "user@test.example", IDToken: ""}}, clients.MockAuthorize{IsAdminResponse: true}, http.StatusFound},
+		{"good", false, opts, errors.New("error"), http.MethodPost, "user@blah.com", "", "", &cryptutil.MockEncoder{}, &sessions.MockSessionStore{Session: &sessions.State{Email: "user@test.example", IDToken: ""}}, clients.MockAuthorize{IsAdminResponse: true}, http.StatusInternalServerError},
+		{"session load error", false, opts, nil, http.MethodPost, "user@blah.com", "", "", &cryptutil.MockEncoder{}, &sessions.MockSessionStore{LoadError: errors.New("err"), Session: &sessions.State{Email: "user@test.example", IDToken: ""}}, clients.MockAuthorize{IsAdminResponse: true}, http.StatusFound},
+		{"non admin users rejected", false, opts, nil, http.MethodPost, "user@blah.com", "", "", &cryptutil.MockEncoder{}, &sessions.MockSessionStore{Session: &sessions.State{RefreshDeadline: time.Now().Add(10 * time.Second), Email: "user@test.example", IDToken: ""}}, clients.MockAuthorize{IsAdminResponse: false}, http.StatusForbidden},
+		{"non admin users rejected on error", false, opts, nil, http.MethodPost, "user@blah.com", "", "", &cryptutil.MockEncoder{}, &sessions.MockSessionStore{Session: &sessions.State{RefreshDeadline: time.Now().Add(10 * time.Second), Email: "user@test.example", IDToken: ""}}, clients.MockAuthorize{IsAdminResponse: true, IsAdminError: errors.New("err")}, http.StatusForbidden},
+		{"save session failure", false, opts, nil, http.MethodPost, "user@blah.com", "", "", &cryptutil.MockEncoder{}, &sessions.MockSessionStore{SaveError: errors.New("err"), Session: &sessions.State{RefreshDeadline: time.Now().Add(10 * time.Second), Email: "user@test.example", IDToken: ""}}, clients.MockAuthorize{IsAdminResponse: true}, http.StatusInternalServerError},
+		{"groups", false, opts, nil, http.MethodPost, "user@blah.com", "group1,group2", "", &cryptutil.MockEncoder{}, &sessions.MockSessionStore{Session: &sessions.State{RefreshDeadline: time.Now().Add(10 * time.Second), Email: "user@test.example", IDToken: ""}}, clients.MockAuthorize{IsAdminResponse: true}, http.StatusFound},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -359,7 +359,7 @@ func TestProxy_Impersonate(t *testing.T) {
 			if err != nil {
 				t.Fatal(err)
 			}
-			p.cipher = tt.cipher
+			p.encoder = tt.cipher
 			p.sessionStore = tt.sessionStore
 			p.AuthorizeClient = tt.authorizer
 			postForm := url.Values{}
diff --git a/proxy/proxy.go b/proxy/proxy.go
index fae786f5f..00f805950 100755
--- a/proxy/proxy.go
+++ b/proxy/proxy.go
@@ -43,11 +43,11 @@ const (
 // ValidateOptions checks that proper configuration settings are set to create
 // a proper Proxy instance
 func ValidateOptions(o config.Options) error {
-	if _, err := cryptutil.NewCipherFromBase64(o.SharedKey); err != nil {
+	if _, err := cryptutil.NewAEADCipherFromBase64(o.SharedKey); err != nil {
 		return fmt.Errorf("proxy: invalid 'SHARED_SECRET': %v", err)
 	}
 
-	if _, err := cryptutil.NewCipherFromBase64(o.CookieSecret); err != nil {
+	if _, err := cryptutil.NewAEADCipherFromBase64(o.CookieSecret); err != nil {
 		return fmt.Errorf("proxy: invalid 'COOKIE_SECRET': %v", err)
 	}
 
@@ -78,7 +78,8 @@ type Proxy struct {
 
 	AuthorizeClient clients.Authorizer
 
-	cipher                 cryptutil.Cipher
+	// cipher                 cipher.AEAD
+	encoder                cryptutil.SecureEncoder
 	cookieName             string
 	cookieDomain           string
 	cookieSecret           []byte
@@ -105,10 +106,12 @@ func New(opts config.Options) (*Proxy, error) {
 	if err != nil {
 		return nil, err
 	}
-	cipher, err := cryptutil.NewCipherFromBase64(opts.CookieSecret)
+	cipher, err := cryptutil.NewAEADCipherFromBase64(opts.CookieSecret)
 	if err != nil {
 		return nil, err
 	}
+	encoder := cryptutil.NewSecureJSONEncoder(cipher)
+
 	if opts.CookieDomain == "" {
 		opts.CookieDomain = sessions.ParentSubdomain(opts.AuthenticateURL.String())
 	}
@@ -120,7 +123,7 @@ func New(opts config.Options) (*Proxy, error) {
 			CookieSecure:   opts.CookieSecure,
 			CookieHTTPOnly: opts.CookieHTTPOnly,
 			CookieExpire:   opts.CookieExpire,
-			CookieCipher:   cipher,
+			Encoder:        encoder,
 		})
 
 	if err != nil {
@@ -130,7 +133,7 @@ func New(opts config.Options) (*Proxy, error) {
 		SharedKey: opts.SharedKey,
 
 		routeConfigs:           make(map[string]*routeConfig),
-		cipher:                 cipher,
+		encoder:                encoder,
 		cookieSecret:           decodedCookieSecret,
 		cookieDomain:           opts.CookieDomain,
 		cookieName:             opts.CookieName,