+function cram_md5_response ($username,$password,$challenge) {
+
+/* Given the challenge from the server, supply the response using
+ cram-md5 (See RFC 2195 for details)
+*/
+$challenge=base64_decode($challenge);
+$hash=bin2hex(hmac_md5($challenge,$password));
+$response=base64_encode($username . " " . $hash) . "\r\n";
+return $response;
+}
+
+function digest_md5_response ($username,$password,$challenge,$service,$host) {
+/* Given the challenge from the server, calculate and return the response-string
+ for digest-md5 authentication. (See RFC 2831 for more details) */
+ $result=digest_md5_parse_challenge($challenge);
+
+// 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;
+ $A1 = bin2hex(hmac_md5($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));
+
+ $reply = 'charset=utf-8,username="' . $username . '",realm="' . $result["realm"] . '",';
+ $reply .= 'nonce="' . $result['nonce'] . '",nc=' . $ncount . ',cnonce="' . $cnonce . '",';
+ $reply .= "digest-uri=\"$digest_uri_value\",response=$response_value";
+ $reply .= ',qop=' . $qop_value;
+ $reply = base64_encode($reply);
+ return $reply . "\r\n";
+
+}
+
+function digest_md5_parse_challenge($challenge) {
+/* This function parses the challenge sent during DIGEST-MD5 authentication and
+ returns an array. See the RFC for details on what's in the challenge string.
+*/
+ $challenge=base64_decode($challenge);
+ while (isset($challenge)) {
+ if ($challenge{0} == ',') { // First char is a comma, must not be 1st time through loop
+ $challenge=substr($challenge,1);
+ }
+ $key=explode('=',$challenge,2);
+ $challenge=$key[1];
+ $key=$key[0];
+ if ($challenge{0} == '"') {
+ // We're in a quoted value
+ // Drop the first quote, since we don't care about it
+ $challenge=substr($challenge,1);
+ // Now explode() to the next quote, which is the end of our value
+ $val=explode('"',$challenge,2);
+ $challenge=$val[1]; // The rest of the challenge, work on it in next iteration of loop
+ $value=explode(',',$val[0]);
+ // Now, for those quoted values that are only 1 piece..
+ if (sizeof($value) == 1) {
+ $value=$value[0]; // Convert to non-array
+ }
+ } else {
+ // We're in a "simple" value - explode to next comma
+ $val=explode(',',$challenge,2);
+ if (isset($val[1])) {
+ $challenge=$val[1];
+ } else {
+ unset($challenge);
+ }
+ $value=$val[0];
+ }
+ $parsed["$key"]=$value;
+ } // End of while loop
+ return $parsed;
+}
+
+function hmac_md5($data, $key='') {
+ // Creates a HMAC digest that can be used for auth purposes
+ // See RFCs 2104, 2617, 2831
+ // Uses mhash() extension if available
+ if (extension_loaded('mhash')) {
+ if ($key== '') {
+ $mhash=mhash(MHASH_MD5,$data);
+ } else {
+ $mhash=mhash(MHASH_MD5,$data,$key);
+ }
+ return $mhash;
+ }
+ if (!$key) {
+ return pack('H*',md5($data));
+ }
+ $key = str_pad($key,64,chr(0x00));
+ if (strlen($key) > 64) {
+ $key = pack("H*",md5($key));
+ }
+ $k_ipad = $key ^ str_repeat(chr(0x36), 64) ;
+ $k_opad = $key ^ str_repeat(chr(0x5c), 64) ;
+ /* Heh, let's get recursive. */
+ $hmac=hmac_md5($k_opad . pack("H*",md5($k_ipad . $data)) );
+ return $hmac;
+}
+