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암호화 관련 질문[사례드릴게요]
2015.07.16 17:22
몇시간 해보다 안되서 여기 남깁니다. password 암호화 된 부분에 대해 좀 풀고 싶습니다.
스카이프 아이디 <brownkoo> 입니다. 방법좀 알려주시는분 사례드릴게요...ㅜ..ㅜ 스트레스 하도받아서 일케 여기 올립니다. 대체 어딜 수정해야될지 모르겠네요.스카이프 연락주셔요~
class Password
{
/**
* @brief Return the list of hashing algorithms supported by this server
* @return array
*/
public function getSupportedAlgorithms()
{
$retval = array();
if(function_exists('hash_hmac') && in_array('sha256', hash_algos()))
{
$retval['pbkdf2'] = 'pbkdf2';
}
if(version_compare(PHP_VERSION, '5.3.7', '>=') && defined('CRYPT_BLOWFISH'))
{
$retval['bcrypt'] = 'bcrypt';
}
$retval['md5'] = 'md5';
return $retval;
}
/**
* @brief Return the best hashing algorithm supported by this server
* @return string
*/
public function getBestAlgorithm()
{
$algos = $this->getSupportedAlgorithms();
return key($algos);
}
/**
* @brief Return the currently selected hashing algorithm
* @return string
*/
public function getCurrentlySelectedAlgorithm()
{
if(function_exists('getModel'))
{
$config = getModel('member')->getMemberConfig();
$algorithm = $config->password_hashing_algorithm;
if(strval($algorithm) === '')
{
$algorithm = 'md5'; // Historical default for XE
}
}
else
{
$algorithm = 'md5';
}
return $algorithm;
}
/**
* @brief Return the currently configured work factor for bcrypt and other adjustable algorithms
* @return int
*/
public function getWorkFactor()
{
if(function_exists('getModel'))
{
$config = getModel('member')->getMemberConfig();
$work_factor = $config->password_hashing_work_factor;
if(!$work_factor || $work_factor < 4 || $work_factor > 31)
{
$work_factor = 8; // Reasonable default
}
}
else
{
$work_factor = 8;
}
return $work_factor;
}
/**
* @brief Create a hash using the specified algorithm
* @param string $password The password
* @param string $algorithm The algorithm (optional)
* @return string
*/
public function createHash($password, $algorithm = null)
{
if($algorithm === null)
{
$algorithm = $this->getCurrentlySelectedAlgorithm();
}
if(!array_key_exists($algorithm, $this->getSupportedAlgorithms()))
{
return false;
}
$password = trim($password);
switch($algorithm)
{
case 'md5':
return md5($password);
case 'pbkdf2':
$iterations = pow(2, $this->getWorkFactor() + 5);
$salt = $this->createSecureSalt(12, 'alnum');
$hash = base64_encode($this->pbkdf2($password, $salt, 'sha256', $iterations, 24));
return 'sha256:'.sprintf('%07d', $iterations).':'.$salt.':'.$hash;
case 'bcrypt':
return $this->bcrypt($password);
default:
return false;
}
}
/**
* @brief Check if a password matches a hash
* @param string $password The password
* @param string $hash The hash
* @param string $algorithm The algorithm (optional)
* @return bool
*/
public function checkPassword($password, $hash, $algorithm = null)
{
if($algorithm === null)
{
$algorithm = $this->checkAlgorithm($hash);
}
$password = trim($password);
switch($algorithm)
{
case 'md5':
return md5($password) === $hash || md5(sha1(md5($password))) === $hash;
case 'mysql_old_password':
return (class_exists('Context') && substr(Context::getDBType(), 0, 5) === 'mysql') ?
DB::getInstance()->isValidOldPassword($password, $hash) : false;
case 'mysql_password':
return $hash[0] === '*' && substr($hash, 1) === strtoupper(sha1(sha1($password, true)));
case 'pbkdf2':
$hash = explode(':', $hash);
$hash[3] = base64_decode($hash[3]);
$hash_to_compare = $this->pbkdf2($password, $hash[2], $hash[0], intval($hash[1], 10), strlen($hash[3]));
return $this->strcmpConstantTime($hash_to_compare, $hash[3]);
case 'bcrypt':
$hash_to_compare = $this->bcrypt($password, $hash);
return $this->strcmpConstantTime($hash_to_compare, $hash);
default:
return false;
}
}
/**
* @brief Check the algorithm used to create a hash
* @param string $hash The hash
* @return string
*/
function checkAlgorithm($hash)
{
if(preg_match('/^\$2[axy]\$([0-9]{2})\$/', $hash, $matches))
{
return 'bcrypt';
}
elseif(preg_match('/^sha[0-9]+:([0-9]+):/', $hash, $matches))
{
return 'pbkdf2';
}
elseif(strlen($hash) === 32 && ctype_xdigit($hash))
{
return 'md5';
}
elseif(strlen($hash) === 16 && ctype_xdigit($hash))
{
return 'mysql_old_password';
}
elseif(strlen($hash) === 41 && $hash[0] === '*')
{
return 'mysql_password';
}
else
{
return false;
}
}
/**
* @brief Check the work factor of a hash
* @param string $hash The hash
* @return int
*/
function checkWorkFactor($hash)
{
if(preg_match('/^\$2[axy]\$([0-9]{2})\$/', $hash, $matches))
{
return intval($matches[1], 10);
}
elseif(preg_match('/^sha[0-9]+:([0-9]+):/', $hash, $matches))
{
return max(0, round(log($matches[1], 2)) - 5);
}
else
{
return false;
}
}
/**
* @brief Generate a cryptographically secure random string to use as a salt
* @param int $length The number of bytes to return
* @param string $format hex or alnum
* @return string
*/
public function createSecureSalt($length, $format = 'hex')
{
// Find out how many bytes of entropy we really need
switch($format)
{
case 'hex':
$entropy_required_bytes = ceil($length / 2);
break;
case 'alnum':
case 'printable':
$entropy_required_bytes = ceil($length * 3 / 4);
break;
default:
$entropy_required_bytes = $length;
}
// Cap entropy to 256 bits from any one source, because anything more is meaningless
$entropy_capped_bytes = min(32, $entropy_required_bytes);
// Find and use the most secure way to generate a random string
$is_windows = (defined('PHP_OS') && strtoupper(substr(PHP_OS, 0, 3)) === 'WIN');
if(function_exists('openssl_random_pseudo_bytes') && (!$is_windows || version_compare(PHP_VERSION, '5.4', '>=')))
{
$entropy = openssl_random_pseudo_bytes($entropy_capped_bytes);
}
elseif(function_exists('mcrypt_create_iv') && (!$is_windows || version_compare(PHP_VERSION, '5.3.7', '>=')))
{
$entropy = mcrypt_create_iv($entropy_capped_bytes, MCRYPT_DEV_URANDOM);
}
elseif(function_exists('mcrypt_create_iv') && $is_windows)
{
$entropy = mcrypt_create_iv($entropy_capped_bytes, MCRYPT_RAND);
}
elseif(!$is_windows && @is_readable('/dev/urandom'))
{
$fp = fopen('/dev/urandom', 'rb');
$entropy = fread($fp, $entropy_capped_bytes);
fclose($fp);
}
else
{
$entropy = '';
for($i = 0; $i < $entropy_capped_bytes; $i += 2)
{
$entropy .= pack('S', rand(0, 65536) ^ mt_rand(0, 65535));
}
}
// Mixing (see RFC 4086 section 5)
$output = '';
for($i = 0; $i < $entropy_required_bytes; $i += 32)
{
$output .= hash('sha256', $entropy . $i . rand(), true);
}
// Encode and return the random string
switch($format)
{
case 'hex':
return substr(bin2hex($output), 0, $length);
case 'binary':
return substr($output, 0, $length);
case 'printable':
$salt = '';
for($i = 0; $i < $length; $i++)
{
$salt .= chr(33 + (crc32(sha1($i . $output)) % 94));
}
return $salt;
case 'alnum':
default:
$salt = substr(base64_encode($output), 0, $length);
$replacements = chr(rand(65, 90)) . chr(rand(97, 122)) . rand(0, 9);
return strtr($salt, '+/=', $replacements);
}
}
/**
* @brief Generate a temporary password using the secure salt generator
* @param int $length The number of bytes to return
* @return string
*/
public function createTemporaryPassword($length = 16)
{
while(true)
{
$source = base64_encode($this->createSecureSalt(64, 'binary'));
$source = strtr($source, 'iIoOjl10/', '@#$%&*-!?');
$source_length = strlen($source);
for($i = 0; $i < $source_length - $length; $i++)
{
$candidate = substr($source, $i, $length);
if(preg_match('/[a-z]/', $candidate) && preg_match('/[A-Z]/', $candidate) &&
preg_match('/[0-9]/', $candidate) && preg_match('/[^a-zA-Z0-9]/', $candidate))
{
return $candidate;
}
}
}
}
/**
* @brief Generate the PBKDF2 hash of a string using a salt
* @param string $password The password
* @param string $salt The salt
* @param string $algorithm The algorithm (optional, default is sha256)
* @param int $iterations Iteration count (optional, default is 8192)
* @param int $length The length of the hash (optional, default is 32)
* @return string
*/
public function pbkdf2($password, $salt, $algorithm = 'sha256', $iterations = 8192, $length = 24)
{
if(function_exists('hash_pbkdf2'))
{
return hash_pbkdf2($algorithm, $password, $salt, $iterations, $length, true);
}
else
{
$output = '';
$block_count = ceil($length / strlen(hash($algorithm, '', true))); // key length divided by the length of one hash
for($i = 1; $i <= $block_count; $i++)
{
$last = $salt . pack('N', $i); // $i encoded as 4 bytes, big endian
$last = $xorsum = hash_hmac($algorithm, $last, $password, true); // first iteration
for($j = 1; $j < $iterations; $j++) // The other $count - 1 iterations
{
$xorsum ^= ($last = hash_hmac($algorithm, $last, $password, true));
}
$output .= $xorsum;
}
return substr($output, 0, $length);
}
}
/**
* @brief Generate the bcrypt hash of a string using a salt
* @param string $password The password
* @param string $salt The salt (optional, auto-generated if empty)
* @return string
*/
public function bcrypt($password, $salt = null)
{
if($salt === null)
{
$salt = '$2y$'.sprintf('%02d', $this->getWorkFactor()).'$'.$this->createSecureSalt(22, 'alnum');
}
return crypt($password, $salt);
}
/**
* @brief Compare two strings in constant time
* @param string $a The first string
* @param string $b The second string
* @return bool
*/
function strcmpConstantTime($a, $b)
{
$diff = strlen($a) ^ strlen($b);
$maxlen = min(strlen($a), strlen($b));
for($i = 0; $i < $maxlen; $i++)
{
$diff |= ord($a[$i]) ^ ord($b[$i]);
}
return $diff === 0;
}
}
/* End of file : Password.class.php */
/* Location: ./classes/security/Password.class.php */
해당 부분은 건드리지 않는게 좋습니다. 다른 모듈이나 프로그램에서도 Password.clss.php를 이용하기에, 임의로 수정할시 사이트 전체에 걸쳐서 문제가 발생 할 수 있습니다.
반드시 회원 개인의 암호를 평문으로 보관을 해야 할 필요가 있다면, 기존 XE 암호화 된 부분은 건드리지 않고, 별도로 평문을 따로 저장하는게 좋습니다.