echo

crc32

Last updated: Fri, 03 Feb 2012

crypt

(PHP 4, PHP 5)

crypt — Encriptação unidirecional de string (hashing)

Descrição

string crypt ( string $str [, string $salt ] )

crypt() retornará uma string criptografada usando o algoritmo de encriptação Unix Standard DES-based ou ou algoritmos alternativos disponíveis no sistema.

Alguns SO suportam mais de um tipo de codificação. De fato, algumas vezes a codificação Standard DES-based é substituído por MD5-based . O tipo de codificação é definido pelo argumento salt. Na instalação, o PHP determina as possíveis funções de codificação e aceitará salts para outros tipos. Se nenhum salt é fornecido, o PHP auto-gera um salt padrão de 2 caracateres por definição, a menos que o tipo de codificação padrão do sistema seja MD5, nesse caso um salt MD5-compatible aleatório será gerado. O PHP define uma constante com nome CRYPT_SALT_LENGTH que dirá se um salt de 2 caracteres aplica-se ao seu sistema ou se o salt mais comprido de 12 caracteres é aplicável.

O Standard DES-based crypt() retorna o salt como o primeiro two characters da saída. Ele também usa apenas os oito primeiros caracteres da str, então strings longas que começam com os mesmos oito caracteres gerarão o mesmo resultado (quando o mesmo salt é usado).

Em sistemas onde a função crypt() suporta variados tipos de codificação, as seguintes funções são definidas para 0 ou 1 a depender se um dado tipo está disponível:

CRYPT_STD_DES - Codificação Standard DES-based com um salt de 2 caracteres
CRYPT_EXT_DES - Codificação Extended DES-based com um salt de 9 caracateres
CRYPT_MD5 - Codificação MD5 com um salt de 12 caracteres começando com $1$
CRYPT_BLOWFISH - Codificação Blowfish com um salt de 16 caracteres começando com $2$

Parâmetros

str

A string a ser encriptada.

salt

Uma opcional string de salt para base da encriptação. Se não fornecido, será gerado randomicamente pelo PHP cada vez que chamar esta função.

Se você está usando um salt fornecido, você está ciente que o salt é gerado uma vez. Se você está chamando essa função repetidamente, isto pode afetar a aparência e a segurança.

Valor Retornado

Retorna a string encriptada.

Exemplos

Exemplo #1 Exemplos da crypt()


<?php
$password = crypt('mypassword'); // let the salt be automatically generated

/* You should pass the entire results of crypt() as the salt for comparing a
   password, to avoid problems when different hashing algorithms are used. (As
   it says above, standard DES-based password hashing uses a 2-character salt,
   but MD5-based hashing uses 12.) */
if (crypt($user_input, $password) == $password) { 
   echo "Password verified!";
}
?>

Exemplo #2 Usando crypt() com htpasswd


<?php
// Set the password
$password = 'mypassword';

// Get the hash, letting the salt be automatically generated
$hash = crypt($password);
?>

Exemplo #3 Usando crypt() com diferente tipos de encriptação


<?php
if (CRYPT_STD_DES == 1) {
    echo 'Standard DES: ' . crypt('rasmuslerdorf', 'rl') . "\n";
}

if (CRYPT_EXT_DES == 1) {
    echo 'Extended DES: ' . crypt('rasmuslerdorf', '_J9..rasm') . "\n";
}

if (CRYPT_MD5 == 1) {
    echo 'MD5:          ' . crypt('rasmuslerdorf', '$1$rasmusle$') . "\n";
}

if (CRYPT_BLOWFISH == 1) {
    echo 'Blowfish:     ' . crypt('rasmuslerdorf', '$2a$07$rasmuslerd...........$') . "\n";
}
?>

O exemplo acima irá imprimir algo similar a:

Standard DES: rl.3StKT.4T8M
Extended DES: _J9..rasmBYk8r9AiWNc
MD5:          $1$rasmusle$rISCgZzpwk3UhDidwXvin0
Blowfish:     $2a$07$rasmuslerd............nIdrcHdxcUxWomQX9j6kvERCFjTg7Ra

Notas

Nota: Não há função decrypt, visto que crypt() usa um algoritmo unidirecional.

Veja Também

md5() - Calcula o "hash MD5" de uma string
A extensão Mcrypt
A man page do Unix para sua função crypt para mais informação

echo

crc32

Last updated: Fri, 03 Feb 2012

User Contributed Notes
crypt

Sorky
03-Feb-2012 11:03


$salt = substr(str_shuffle("./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"), -22);

ircmaxell at php dot net
01-Feb-2012 12:38


Harry at simans:



That's absolutely not necessary.  Crypt will automatically peel off the salt for you (and include it in the output).  You can add a function to generate the salt for you, but the crypt function works the same way your wrapper does:



<?php

function makeSalt() {

    static $seed = "./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";

    $algo = '$2a';

    $strength = '$08';

    $salt = '$';

    for ($i = 0; $i < 22; $i++) {

        $salt .= substr($seed, mt_rand(0, 63), 1);

    }

    return $algo . $strength . $salt;

}



function makeHash($password) {

    return crypt($password, makeSalt());

}



function verifyHash($password, $hash) {

    return $hash == crypt($password, $hash);

}

?>



Which then means that this relation will always hold:



<?php



true === verifyHash($password, makeHash($password));



?>



So there's no need to store the salt separately, since crypt() stores it inline for you...

harry at simans dot net
27-Sep-2011 01:34


I made a nice little wrapper function for crypt():





<?php


function hasher($info, $encdata = false)


{


  $strength = "08";


  //if encrypted data is passed, check it against input ($info)


  if ($encdata) {


    if (substr($encdata, 0, 60) == crypt($info, "$2a$".$strength."$".substr($encdata, 60))) {


      return true;


    }


    else {


      return false;


    }


  }


  else {


  //make a salt and hash it with input, and add salt to end


  $salt = "";


  for ($i = 0; $i < 22; $i++) {


    $salt .= substr("./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789", mt_rand(0, 63), 1);


  }


  //return 82 char string (60 char hash & 22 char salt)


return crypt($info, "$2a$".$strength."$".$salt).$salt;


}


}


?>





This wrapper will accept a string as input and hash it, and output the hash result of the string and salt together, plus the salt added on the end. You can then store that output in a db, and pass it on to the function as the 2nd parameter when you go to verify it, along with the user input or whatever as the first.





Examples:





<?php


$hash = hasher($userinput);


if ($hash == hasher($userinput, $hash) {//authed}


?>





Neat huh?

eleljrk at gmail dot com
21-Sep-2011 08:23


I've seen many CRYPT_BLOWFISH salt generators, but none REALLY go into the depth of it. This give you a RANDOM string of 22 characters, the string can contain ANY OF THE ALLOWED characters for the salt. I wont claim this the best solution, but this is fairly much everything you can do with a random salt generator.



<?php



public function getSalt() {



    $c = explode(" ", ". / a A b B c C d D e E f F g G h H i I j J k K l L m M n N o O p P q Q r R s S t T u U v V w W x X y Y z Z 0 1 2 3 4 5 6 7 8 9");

    $ks = array_rand($c, 22);



    $s = "";

    foreach($ks as $k) { $s .= $c[$k]; }



    return $s;



}



?>



Take note that every allowed character is inside the $c variable, $s is the salt, $ks is for keys to use in salt and $k is key. There is probably a better and shorter script out there, but this is solid enough for me.



Have fun with the code.

kaminski at istori dot com
05-Feb-2011 01:43


Here is an expression to generate pseudorandom salt for the CRYPT_BLOWFISH hash type:



<?php $salt = substr(str_replace('+', '.', base64_encode(pack('N4', mt_rand(), mt_rand(), mt_rand(), mt_rand()))), 0, 22); ?>



It is intended for use on systems where mt_getrandmax() == 2147483647.



The salt created will be 128 bits in length, padded to 132 bits and then expressed in 22 base64 characters.  (CRYPT_BLOWFISH only uses 128 bits for the salt, even though there are 132 bits in 22 base64 characters.  If you examine the CRYPT_BLOWFISH input and output, you can see that it ignores the last four bits on input, and sets them to zero on output.)



Note that the high-order bits of the four 32-bit dwords returned by mt_rand() will always be zero (since mt_getrandmax == 2^31), so only 124 of the 128 bits will be pseudorandom.  I found that acceptable for my application.

Robin Leffmann
25-Dec-2010 04:23


The salts for crypt() must follow the usual base64 ASCII pattern (./0-9A-Za-z only), but the payload string can contain any binary data.

Thomas Praxl
10-Jan-2010 07:28


Note that crypt can cause hangs on Windows OS when used with a salt. This applies only to certain circumstances.

php at nospam dot nowhere dot com
26-Aug-2009 04:21


The makesalt() function code below when used to create an MD5 salt, produces a salt with characters not typically in a salt used by operating system crypt functions.  Some of these characters may have unintended side effects depending on how they are used - including the following: @ ` ~ \ | {}.



I am using the following to create MD5-Crypt hashes, (yes, I am assuming CRYPT_MD5 support is present).



<?php

function md5crypt($password){

    // create a salt that ensures crypt creates an md5 hash

    $base64_alphabet='ABCDEFGHIJKLMNOPQRSTUVWXYZ'

                    .'abcdefghijklmnopqrstuvwxyz0123456789+/';

    $salt='$1$';

    for($i=0; $i<9; $i++){

        $salt.=$base64_alphabet[rand(0,63)];

    }

    // return the crypt md5 password

    return crypt($password,$salt.'$');

}

?>

addiakogiannis at isds dot gr
13-Jul-2007 12:46


Two siple functions for encrypting and decrypting with RIJNDAEL 256



function RIJNDAEL_encrypt($text){



    $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);

    $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);

    $key = "This is a very secret key";

    return base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $key, $text, MCRYPT_MODE_ECB, $iv));

    

}



function RIJNDAEL_decrypt($text){



    $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);

    $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);

    $key = "This is a very secret key";

  //I used trim to remove trailing spaces

return trim(mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $key, base64_decode($text), MCRYPT_MODE_ECB, $iv));

    

}



//example

echo RIJNDAEL_decrypt(RIJNDAEL_encrypt('Her name was lola!'));

leth at nowhere dot not
06-Apr-2007 04:51


for me(on OpenBSD4.0+Apache 1.3(standard)+php4.3.10) blowfish seems to work if you do something like this:



    if (CRYPT_BLOWFISH == 1)

    {

        $salt="this should really be a long line of salt";

        $blowfish_salt = "\$2a\$07\$".substr($salt, 0, CRYPT_SALT_LENGTH);

        echo crypt($pass, $blowfish_salt);

    }



of course with $salt set as a good long salt.

Jou
05-Apr-2007 10:52


I found out that you can use php:s crypt function to change  the user/root password in Linux distributions (at least in Slackware).



You just have to change the encrypted password for the user in the /etc/shadow file with the output from crypt("newpassword");

mikey_nich (at) hotmáil . com
04-Mar-2007 04:47


Are you using Apache2 on f.i. WinXP and want to create .htpasswd files via php? Then you need to use the APR1-MD5 encryption method. Here is a function for that:



<?php



function crypt_apr1_md5($plainpasswd) {

    $salt = substr(str_shuffle("abcdefghijklmnopqrstuvwxyz0123456789"), 0, 8);

    $len = strlen($plainpasswd);

    $text = $plainpasswd.'$apr1$'.$salt;

    $bin = pack("H32", md5($plainpasswd.$salt.$plainpasswd));

    for($i = $len; $i > 0; $i -= 16) { $text .= substr($bin, 0, min(16, $i)); }

    for($i = $len; $i > 0; $i >>= 1) { $text .= ($i & 1) ? chr(0) : $plainpasswd{0}; }

    $bin = pack("H32", md5($text));

    for($i = 0; $i < 1000; $i++) {

        $new = ($i & 1) ? $plainpasswd : $bin;

        if ($i % 3) $new .= $salt;

        if ($i % 7) $new .= $plainpasswd;

        $new .= ($i & 1) ? $bin : $plainpasswd;

        $bin = pack("H32", md5($new));

    }

    for ($i = 0; $i < 5; $i++) {

        $k = $i + 6;

        $j = $i + 12;

        if ($j == 16) $j = 5;

        $tmp = $bin[$i].$bin[$k].$bin[$j].$tmp;

    }

    $tmp = chr(0).chr(0).$bin[11].$tmp;

    $tmp = strtr(strrev(substr(base64_encode($tmp), 2)),

    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/",

    "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz");

    return "$"."apr1"."$".$salt."$".$tmp;

}



?>

tserong at sgi dot com
13-Dec-2006 10:18


Blowfish doesn't use a sixteen character salt, it uses sixteen *bytes* of salt.  So (courtesy of the docs for the Crypt::Eksblowfish::Bcrypt Perl module), it's:



    "$2", optional "a", "$", two digits, "$", and 22 base 64 digits



If the salt is not long enough, crypt will return "*0" and you will have no idea what is wrong.  Interestingly, the example in the documentation with a trailing '$' in the salt does not work.  Replace the '$' with a '.', and the output appears as advertised.

picolobo at pilab dot dyndns dot org
21-Sep-2006 10:49


I had problems with ENCRYPT MySQL function when i tried to compare with the encrypted password (with ENCRYPT).



Another solution i read from "UNIX Advanced programming" where i found about the UNIX system call "crypt()":



Password="tB" //The two first letters of encrypted password



SELECT password from users where Password=ENCRYPT('".$_POST['password']."',Password)



mysql> select password from users where password=encrypt('pasword','tB');

+---------------+

| password      |

+---------------+

| tBY8OVuabSiTU |

+---------------+

1 row in set (0.01 sec)



Bye.



> topace at lightbox dot org

> 22-Sep-2005 06:34

>

> To authenticate against a stored crypt in MySQL, simply use:

>

> SELECT ................

>           AND Password=ENCRYPT('".$_POST['password']."',Password)

solar at openwall dot com
23-Dec-2005 09:20


With different password hashing methods supported on different systems and with the need to generate salts with your own PHP code in order to use the more advanced / more secure methods, it takes special knowledge to use crypt() optimally, producing strong password hashes.  Other message digest / hashing functions supported by PHP, such as md5() and sha1(), are really no good for password hashing if used naively, resulting in hashes which may be brute-forced at rates much higher than those possible for hashes produced by crypt().



I have implemented a PHP password hashing framework (in PHP, tested with all of PHP 3, 4, and 5) which hides the complexity from your PHP applications (no need for you to worry about salts, etc.), yet does things in almost the best way possible given the constraints of the available functions.  The homepage for the framework is:



http://www.openwall.com/phpass/



I have placed this code in the public domain, so there are no copyrights or licensing restrictions to worry about.



P.S. I have 10 years of experience in password (in)security and I've developed several other password security tools and libraries.  So most people can feel confident they're getting this done better by using my framework than they could have done it on their own.

hotdog (at) gmx (dot) net
16-Nov-2005 05:34


WRONG:



$mypassword = "toto";

$smd5_pass = "{SMD5}......." // in openldap



if (preg_match ("/{SMD5}/i", $smd5_pass))

 {

  $encrypted = substr($md5_pass, 6);

  $hash = base64_decode($encrypted);

  $salt = substr($hash,16);

  $mhashed =  mhash(MHASH_MD5, $mypassword . $salt) ;

  $without_salt = explode($salt,$hash_hex);

   if ($without_salt[0] == $mhashed) {

    echo "Password verified <br>";

    } else {

    echo "Password Not verified<br>";

    }

 }



$without_salt = explode($salt,$hash_hex); should be $without_salt = explode($salt,$hash); 



RIGHT:



$mypassword = "toto";

$smd5_pass = "{SMD5}......." // in openldap



if (preg_match ("/{SMD5}/i", $smd5_pass))

 {

  $encrypted = substr($md5_pass, 6);

  $hash = base64_decode($encrypted);

  $salt = substr($hash,16);

  $mhashed =  mhash(MHASH_MD5, $mypassword . $salt) ;

  $without_salt = explode($salt,$hash);

   if ($without_salt[0] == $mhashed) {

    echo "Password verified <br>";

    } else {

    echo "Password Not verified<br>";

    }

 }

Vlad Alexa Mancini mancin at nextcode dot org
15-May-2005 10:57


cleaner version of shadow() and with more ascii chars



<?php



function shadow ($input){

         for ($n = 0; $n < 9; $n++){

              $s .= chr(rand(64,126));

         }

         $seed =  "$1$".$s."$";

         $return = crypt($input,$seed);

    return $return;

}



>

thorhajo at gmail dot com
02-Sep-2004 12:34


Here's a little function I wrote to generate MD5 password hashes in the format they're found in /etc/shadow:



function shadow($password)

{

  $hash = '';

  for($i=0;$i<8;$i++)

  {

    $j = mt_rand(0,53);

    if($j<26)$hash .= chr(rand(65,90));

    else if($j<52)$hash .= chr(rand(97,122));

    else if($j<53)$hash .= '.';

    else $hash .= '/';

  }

  return crypt($password,'$1$'.$hash.'$');

}



I've written this so that each character in the a-zA-Z./ set has a 1/54 of a chance of being selected (26 + 26 + 2 = 54), thus being statistically even.

aidan at php dot net
05-Jul-2004 04:52


Text_Password allows one to create pronounceable and unpronounceable passwords.



http://pear.php.net/package/text_password

echo

crc32

Last updated: Fri, 03 Feb 2012