diff --git a/group/client.go b/group/client.go
index a018e2c..4dfaa8c 100644
--- a/group/client.go
+++ b/group/client.go
@@ -31,8 +31,8 @@ type Password RawPassword
 // out of memory when doing too many BCrypt hashes at the same time.
 var hashSemaphore = make(chan struct{}, runtime.GOMAXPROCS(-1))
 
-// constantTimeCompare compares a and b in time proportional to the length of a.
-func constantTimeCompare(a, b string) bool {
+// ConstantTimeCompare compares a and b in time proportional to the length of a.
+func ConstantTimeCompare(a, b string) bool {
 	as := []byte(a)
 	bs := make([]byte, len(as))
 	copy(bs, b)
@@ -48,7 +48,7 @@ func (p Password) Match(pw string) (bool, error) {
 		if p.Key == nil {
 			return false, errors.New("missing key")
 		}
-		return constantTimeCompare(pw, *p.Key), nil
+		return ConstantTimeCompare(pw, *p.Key), nil
 	case "wildcard":
 		return true, nil
 	case "pbkdf2":
diff --git a/group/group_test.go b/group/group_test.go
index 2af44eb..018592c 100644
--- a/group/group_test.go
+++ b/group/group_test.go
@@ -25,7 +25,7 @@ func TestConstantTimeCompare(t *testing.T) {
 	}
 
 	for _, test := range tests {
-		e := constantTimeCompare(test.a, test.b)
+		e := ConstantTimeCompare(test.a, test.b)
 		if e != (test.a == test.b) {
 			t.Errorf("constantTimeCompare(%v, %v): got %v",
 				test.a, test.b, e,