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Last updated: Fri, 26 Jan 2007

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# mhash_keygen_s2k

(PHP 4 >= 4.0.4, PHP 5)

mhash_keygen_s2k -- Generates a key

## Описание

string mhash_keygen_s2k ( int hash, string password, string salt, int bytes )

Generates a key according to the `hash` given a user provided `password`.

This is the Salted S2K algorithm as specified in the OpenPGP document (RFC 2440).

Keep in mind that user supplied passwords are not really suitable to be used as keys in cryptographic algorithms, since users normally choose keys they can write on keyboard. These passwords use only 6 to 7 bits per character (or less). It is highly recommended to use some kind of transformation (like this function) to the user supplied key.

## Список параметров

`hash`

  The hash id used to create the key. One of the `MHASH_XXX` constants.

`password`

  User supplied password.

`salt`

  Must be different and random enough for every key you generate in order to create different keys. That salt must be known when you check the keys, thus it is a good idea to append the key to it. Salt has a fixed length of 8 bytes and will be padded with zeros if you supply less bytes.

`bytes`

  The key length, in bytes.

## Возвращаемые значения

Returns the generated key as a string, or `FALSE` on error.

add a note User Contributed Notes
mhash_keygen_s2k
php_at_share-foo.com
16-Jul-2003 11:18
`// given random 8 bits of salt and a clear text password
$clear_pw = "p4ssw0rd" ;
$rand8bites4salt = substr(pack("h*", md5(mt_rand())) , 0, 8);
// This
mhash_keygen_s2k(MHASH_MD5, $clear_pw, $rand8bites4salt, 4) ;
//is the same as this
function myhash_keyge_s2k($pass, $salt, $bytes ){
return substr(pack("H*", md5($salt . $pass)), 0, $bytes);
}
myhash_keyge_s2k($clear_pw, $rand8bites4salt, 4);
// But the latter doesn't require mhash libs.
// -ray ferguson`
add a note
mhash mhash_get_hash_name

Last updated: Fri, 26 Jan 2007
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