Project import generated by Copybara.
GitOrigin-RevId: 63746295f1a5ab5a619056791995793d65529e62
diff --git a/src/lib/GoogleAuthenticator/GoogleAuthenticator.php b/src/lib/GoogleAuthenticator/GoogleAuthenticator.php
new file mode 100644
index 0000000..62bc0cb
--- /dev/null
+++ b/src/lib/GoogleAuthenticator/GoogleAuthenticator.php
@@ -0,0 +1,87 @@
+<?php
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+
+include_once("FixedByteNotation.php");
+
+
+class GoogleAuthenticator {
+ static $PASS_CODE_LENGTH = 6;
+ static $PIN_MODULO;
+ static $SECRET_LENGTH = 20;
+
+ public function __construct() {
+ self::$PIN_MODULO = pow(10, self::$PASS_CODE_LENGTH);
+ }
+
+ public function checkCode($secret,$code) {
+ $time = floor(time() / 30);
+ for ( $i = -1; $i <= 1; $i++) {
+
+ if ($this->getCode($secret,$time + $i) == $code) {
+ return true;
+ }
+ }
+
+ return false;
+
+ }
+
+ public function getCode($secret,$time = null) {
+
+ if (!$time) {
+ $time = floor(time() / 30);
+ }
+ $base32 = new FixedBitNotation(5, 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567', TRUE, TRUE);
+ $secret = $base32->decode($secret);
+
+ $time = pack("N", $time);
+ $time = str_pad($time,8, chr(0), STR_PAD_LEFT);
+
+ $hash = hash_hmac('sha1',$time,$secret,true);
+ $offset = ord(substr($hash,-1));
+ $offset = $offset & 0xF;
+
+ $truncatedHash = self::hashToInt($hash, $offset) & 0x7FFFFFFF;
+ $pinValue = str_pad($truncatedHash % self::$PIN_MODULO,6,"0",STR_PAD_LEFT);;
+ return $pinValue;
+ }
+
+ protected function hashToInt($bytes, $start) {
+ $input = substr($bytes, $start, strlen($bytes) - $start);
+ $val2 = unpack("N",substr($input,0,4));
+ return $val2[1];
+ }
+
+ public function getUrl($user, $hostname, $secret) {
+ $url = sprintf("otpauth://totp/%s@%s?secret=%s", $user, $hostname, $secret);
+ $encoder = "https://www.google.com/chart?chs=200x200&chld=M|0&cht=qr&chl=";
+ $encoderURL = sprintf( "%sotpauth://totp/%s@%s&secret=%s",$encoder, $user, $hostname, $secret);
+
+ return $encoderURL;
+
+ }
+
+ public function generateSecret() {
+ $secret = "";
+ for($i = 1; $i<= self::$SECRET_LENGTH;$i++) {
+ $c = random_int(0,255);
+ $secret .= pack("c",$c);
+ }
+ $base32 = new FixedBitNotation(5, 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567', TRUE, TRUE);
+ return $base32->encode($secret);
+
+
+ }
+
+}