+/**
+ * Given the challenge from the server, supply the response using cram-md5 (See
+ * RFC 2195 for details)
+ *
+ * @param string $username User ID
+ * @param string $password User password supplied by User
+ * @param string $challenge The challenge supplied by the server
+ * @return string The response to be sent to the IMAP server
+ * @since 1.4.0
+ */
+function cram_md5_response ($username,$password,$challenge) {
+ $challenge=base64_decode($challenge);
+ $hash=bin2hex(hmac_md5($challenge,$password));
+ $response=base64_encode($username . " " . $hash) . "\r\n";
+ return $response;
+}
+
+/**
+ * Return Digest-MD5 response.
+ * Given the challenge from the server, calculate and return the
+ * response-string for digest-md5 authentication. (See RFC 2831 for more
+ * details)
+ *
+ * @param string $username User ID
+ * @param string $password User password supplied by User
+ * @param string $challenge The challenge supplied by the server
+ * @param string $service The service name, usually 'imap'; it is used to
+ * define the digest-uri.
+ * @param string $host The host name, usually the server's FQDN; it is used to
+ * define the digest-uri.
+ * @param string $authz Authorization ID (since 1.5.2)
+ * @return string The response to be sent to the IMAP server
+ * @since 1.4.0
+ */
+function digest_md5_response ($username,$password,$challenge,$service,$host,$authz='') {
+ $result=digest_md5_parse_challenge($challenge);
+ //FIXME we should check that $result contains the expected values that we use below
+
+ // verify server supports qop=auth
+ // $qop = explode(",",$result['qop']);
+ //if (!in_array("auth",$qop)) {
+ // rfc2831: client MUST fail if no qop methods supported
+ // return false;
+ //}
+ $cnonce = base64_encode(bin2hex(hmac_md5(microtime())));
+ $ncount = "00000001";
+
+ /* This can be auth (authentication only), auth-int (integrity protection), or
+ auth-conf (confidentiality protection). Right now only auth is supported.
+ DO NOT CHANGE THIS VALUE */
+ $qop_value = "auth";
+
+ $digest_uri_value = $service . '/' . $host;
+
+ // build the $response_value
+ //FIXME This will probably break badly if a server sends more than one realm
+ $string_a1 = utf8_encode($username).":";
+ $string_a1 .= utf8_encode($result['realm']).":";
+ $string_a1 .= utf8_encode($password);
+ $string_a1 = hmac_md5($string_a1);
+ $A1 = $string_a1 . ":" . $result['nonce'] . ":" . $cnonce;
+ if(!empty($authz)) {
+ $A1 .= ":" . utf8_encode($authz);
+ }
+ $A1 = bin2hex(hmac_md5($A1));
+ $A2 = "AUTHENTICATE:$digest_uri_value";
+ // If qop is auth-int or auth-conf, A2 gets a little extra
+ if ($qop_value != 'auth') {
+ $A2 .= ':00000000000000000000000000000000';
+ }
+ $A2 = bin2hex(hmac_md5($A2));
+
+ $string_response = $result['nonce'] . ':' . $ncount . ':' . $cnonce . ':' . $qop_value;
+ $response_value = bin2hex(hmac_md5($A1.":".$string_response.":".$A2));