Generate a hash value (message digest)

hash_update
Mcrypt
Hash Functions
PHP Manual

# hash

(PHP 5 >= 5.1.2, PECL hash >= 1.1)

hash — Generate a hash value (message digest)

### Description

string hash ( string `$algo` , string `$data` [, bool `$raw_output` = false ] )

### Parameters

`algo`

  Name of selected hashing algorithm (e.g. "md5", "sha256", "haval160,4", etc..)

`data`

  Message to be hashed.

`raw_output`

  When set to `TRUE`, outputs raw binary data. `FALSE` outputs lowercase hexits.

### Return Values

Returns a string containing the calculated message digest as lowercase hexits unless `raw_output` is set to true in which case the raw binary representation of the message digest is returned.

### Changelog

Version | Description
--- | ---
5.4.0 | The tiger algorithm now uses big-endian byte ordering. See also example below.

### Examples

Example #1 A hash() example

`<?php
echo hash('ripemd160', 'The quick brown fox jumped over the lazy dog.');
?>`

The above example will output:

    ec457d0a974c48d5685a7efa03d137dc8bbde7e3

Example #2 Calculate pre PHP-5.4 tiger hashes with PHP-5.4 and higher

`<?php
function old_tiger($data = "", $width=192, $rounds = 3) {
return substr(
implode(
array_map(
function ($h) {
return str_pad(bin2hex(strrev($h)), 16, "0");
},
str_split(hash("tiger192,$rounds", $data, true), 8)
)
),
0, 48-(192-$width)/4
);
}
echo hash('tiger192,3', 'a-string'), PHP_EOL;
echo old_tiger('a-string'), PHP_EOL;
?>`

Output of the above example in PHP 5.3:

    146a7492719b3564094efe7abbd40a7416fd900179d02773
    64359b7192746a14740ad4bb7afe4e097327d0790190fd16

Output of the above example in PHP 5.4:

    64359b7192746a14740ad4bb7afe4e097327d0790190fd16
    146a7492719b3564094efe7abbd40a7416fd900179d02773

### See Also

- hash_file() - Generate a hash value using the contents of a given file
- hash_hmac() - Generate a keyed hash value using the HMAC method
- hash_init() - Initialize an incremental hashing context
- md5() - Calculate the md5 hash of a string
- sha1() - Calculate the sha1 hash of a string

hash_update
Mcrypt
Hash Functions
PHP Manual