Actualización

plugin/ims_lti/vendor/oauth1/code/OAuthSignatureMethod.php

@@ -0,0 +1,55 @@
+<?php
+
+/**
+ * A class for implementing a Signature Method
+ * See section 9 ("Signing Requests") in the spec
+ */
+abstract class OAuthSignatureMethod {
+  /**
+   * Needs to return the name of the Signature Method (ie HMAC-SHA1)
+   * @return string
+   */
+  abstract public function get_name();
+
+  /**
+   * Build up the signature
+   * NOTE: The output of this function MUST NOT be urlencoded.
+   * the encoding is handled in OAuthRequest when the final
+   * request is serialized
+   * @param OAuthRequest $request
+   * @param OAuthConsumer $consumer
+   * @param OAuthToken $token
+   * @return string
+   */
+  abstract public function build_signature($request, $consumer, $token);
+
+  /**
+   * Verifies that a given signature is correct
+   * @param OAuthRequest $request
+   * @param OAuthConsumer $consumer
+   * @param OAuthToken $token
+   * @param string $signature
+   * @return bool
+   */
+  public function check_signature($request, $consumer, $token, $signature) {
+    $built = $this->build_signature($request, $consumer, $token);
+
+    // Check for zero length, although unlikely here
+    if (strlen($built) == 0 || strlen($signature) == 0) {
+      return false;
+    }
+
+    if (strlen($built) != strlen($signature)) {
+      return false;
+    }
+
+    // Avoid a timing leak with a (hopefully) time insensitive compare
+    $result = 0;
+    for ($i = 0; $i < strlen($signature); $i++) {
+      $result |= ord($built[$i]) ^ ord($signature[$i]);
+    }
+
+    return $result == 0;
+  }
+}
+