diff --git a/doc/operation/Sign.md b/doc/operation/Sign.md
index 4dea88e8..32f4e88a 100644
--- a/doc/operation/Sign.md
+++ b/doc/operation/Sign.md
@@ -136,7 +136,7 @@ $key1 = JWKFactory::createFromKeyFile(
 // We load the second key to sign using algorithm HS512
 $key2 = JWKFactory::createFromValues(
     [
-        'kty' => 'oct,
+        'kty' => 'oct',
         'kid' => 'My Shared key',
         'use' => 'sig',
         'alg' => 'HS512',