Add a method to SignatureAlgorithm to get the key

Signed-off-by: Jaime Pérez <jaimepc@gmail.com>

Author: jaimeperez

src/Alg/Signature/AbstractSigner.php

@@ -78,6 +78,15 @@ public function getDigest(): string
     }
 
 
+    /**
+     * @return AbstractKey
+     */
+    public function getKey(): AbstractKey
+    {
+        return $this->key;
+    }
+
+
     /**
      * @param \SimpleSAML\XMLSecurity\Backend\SignatureBackend $backend
      */

src/Alg/SignatureAlgorithm.php

@@ -3,6 +3,7 @@
 namespace SimpleSAML\XMLSecurity\Alg;
 
 use SimpleSAML\XMLSecurity\Backend\SignatureBackend;
+use SimpleSAML\XMLSecurity\Key\AbstractKey;
 
 /**
  * An interface representing algorithms that can be used for digital signatures.
@@ -35,6 +36,13 @@ public function getDigest(): string;
     public function getAlgorithmId(): string;
 
 
+    /**
+     * Get the key to use with this signature algorithm.
+     *
+     * @return AbstractKey
+     */
+    public function getKey(): AbstractKey;
+
 
     /**
      * Set the backend to use for actual computations by this algorithm.

src/Backend/HMAC.php

@@ -62,7 +62,7 @@ public function sign(AbstractKey $key, string $plaintext): string
     /**
      * Verify a signature with this cipher and a given key.
      *
-     * @param \SimpleSAML\XMLSecurity\Key\AbstractKey $key The key to use to.
+     * @param \SimpleSAML\XMLSecurity\Key\AbstractKey $key The key to use to verify the signature.
      * @param string $plaintext The original signed text.
      * @param string $signature The (binary) signature to verify.
      *