<?php
namespace Braintree;
/**
* Digest encryption module
* Digest creates an HMAC-SHA1 hash for encrypting messages
*/
class Digest
{
public static function hexDigestSha1($key, $string)
{
if(function_exists('hash_hmac')) {
return self::_builtInHmacSha1($string, $key);
} else {
return self::_hmacSha1($string, $key);
}
}
public static function hexDigestSha256($key, $string)
{
return hash_hmac('sha256', $string, hash('sha256', $key, true));
}
public static function secureCompare($left, $right)
{
if (strlen($left) != strlen($right)) {
return false;
}
$leftBytes = unpack("C*", $left);
$rightBytes = unpack("C*", $right);
$result = 0;
for ($i = 1; $i <= count($leftBytes); $i++) {
$result = $result | ($leftBytes[$i] ^ $rightBytes[$i]);
}
return $result == 0;
}
public static function _builtInHmacSha1($message, $key)
{
return hash_hmac('sha1', $message, sha1($key, true));
}
public static function _hmacSha1($message, $key)
{
$pack = 'H40';
$keyDigest = sha1($key,true);
$innerPad = str_repeat(chr(0x36), 64);
$outerPad = str_repeat(chr(0x5C), 64);
for ($i = 0; $i < 20; $i++) {
$innerPad{$i} = $keyDigest{$i} ^ $innerPad{$i};
$outerPad{$i} = $keyDigest{$i} ^ $outerPad{$i};
}
return sha1($outerPad.pack($pack, sha1($innerPad.$message)));
}
}
class_alias('Braintree\Digest', 'Braintree_Digest');