+<?php
+
+namespace Friendica\Security\OAuth1\Signature;
+
+use Friendica\Security\OAuth1\OAuthRequest;
+
+/**
+ * The RSA-SHA1 signature method uses the RSASSA-PKCS1-v1_5 signature algorithm as defined in
+ * [RFC3447] section 8.2 (more simply known as PKCS#1), using SHA-1 as the hash function for
+ * EMSA-PKCS1-v1_5. It is assumed that the Consumer has provided its RSA public key in a
+ * verified way to the Service Provider, in a manner which is beyond the scope of this
+ * specification.
+ * - Chapter 9.3 ("RSA-SHA1")
+ */
+abstract class OAuthSignatureMethod_RSA_SHA1 extends OAuthSignatureMethod
+{
+ public function get_name()
+ {
+ return "RSA-SHA1";
+ }
+
+ // Up to the SP to implement this lookup of keys. Possible ideas are:
+ // (1) do a lookup in a table of trusted certs keyed off of consumer
+ // (2) fetch via http using a url provided by the requester
+ // (3) some sort of specific discovery code based on request
+ //
+ // Either way should return a string representation of the certificate
+ protected abstract function fetch_public_cert(&$request);
+
+ // Up to the SP to implement this lookup of keys. Possible ideas are:
+ // (1) do a lookup in a table of trusted certs keyed off of consumer
+ //
+ // Either way should return a string representation of the certificate
+ protected abstract function fetch_private_cert(&$request);
+
+ public function build_signature(OAuthRequest $request, \Friendica\Security\OAuth1\OAuthConsumer $consumer, \Friendica\Security\OAuth1\OAuthToken $token = null)
+ {
+ $base_string = $request->get_signature_base_string();
+ $request->base_string = $base_string;
+
+ // Fetch the private key cert based on the request
+ $cert = $this->fetch_private_cert($request);
+
+ // Pull the private key ID from the certificate
+ $privatekeyid = openssl_get_privatekey($cert);
+
+ // Sign using the key
+ openssl_sign($base_string, $signature, $privatekeyid);
+
+ // Release the key resource
+ openssl_free_key($privatekeyid);
+
+ return base64_encode($signature);
+ }
+
+ public function check_signature(OAuthRequest $request, \Friendica\Security\OAuth1\OAuthConsumer $consumer, $signature, \Friendica\Security\OAuth1\OAuthToken $token = null)
+ {
+ $decoded_sig = base64_decode($signature);
+
+ $base_string = $request->get_signature_base_string();
+
+ // Fetch the public key cert based on the request
+ $cert = $this->fetch_public_cert($request);
+
+ // Pull the public key ID from the certificate
+ $publickeyid = openssl_get_publickey($cert);
+
+ // Check the computed signature against the one passed in the query
+ $ok = openssl_verify($base_string, $decoded_sig, $publickeyid);
+
+ // Release the key resource
+ openssl_free_key($publickeyid);
+
+ return $ok == 1;
+ }
+}