md5_file
If you want to hash a large amount of data you can use the hash_init/hash_update/hash_final functions.
This allows you to hash chunks/parts/incremental or whatever you like to call it.
md5
(PHP 4, PHP 5)
md5 — Calculate the md5 hash of a string
Description
string md5
( string
$str
[, bool $raw_output = false
] )
Calculates the MD5 hash of str using the
» RSA Data Security, Inc.
MD5 Message-Digest Algorithm, and returns that hash.
Parameters
-
str -
The string.
-
raw_output -
If the optional
raw_outputis set toTRUE, then the md5 digest is instead returned in raw binary format with a length of 16.
Return Values
Returns the hash as a 32-character hexadecimal number.
Changelog
| Version | Description |
|---|---|
| 5.0.0 |
The raw_output parameter was added.
|
Examples
Example #1 A md5() example
<?php
$str = 'apple';
if (md5($str) === '1f3870be274f6c49b3e31a0c6728957f') {
echo "Would you like a green or red apple?";
}
?>
Notes
Note: Secure password hashing
It is not recommended to use this function to secure passwords, due to the fast nature of this hashing algorithm. See here for details.
See Also
- md5_file() - Calculates the md5 hash of a given file
- sha1_file() - Calculate the sha1 hash of a file
- crc32() - Calculates the crc32 polynomial of a string
- sha1() - Calculate the sha1 hash of a string
- hash() - Generate a hash value (message digest)
add a note
User Contributed Notes
md5 - [14 notes]
John ¶
3 years ago
sebastian dot haller at freesurf dot ch ¶
6 years ago
It has been found, that hash('md5', 'string'); is faster than md5($string):
http://www.php.net/manual/en/function.hash.php
terry _at_ scribendi_com ¶
8 years ago
Do not use the hex strings returned by md5() as a key for MCrypt 256-bit encryption. Hex characters only represent four bits each, so when you take 32 hex characters, you are only really using a 128-bit key, not a 256-bit one.
Using an alphanumeric key generator [A-Za-z0-9] will also only provide a 192-bit key in 32 characters.
Two different MD5s concatenated in raw binary form, or mcrypt_create_iv(32,MCRYPT_DEV_RANDOM) will give you a true 256-bit key string.
John S. ¶
8 years ago
If you want to replicate CPAN Digest::MD5's function md5_base64 in PHP, use this code:
<?php
function md5_base64 ( $data )
{
return preg_replace('/=+$/','',base64_encode(pack('H*',md5($data))));
}
?>
admin at gadelkareem dot com ¶
5 years ago
MySQL MD() will not give you the same hash if character set is different.
ex :
<?php
#suppose table_name CHARSET=UTF8
#$md5 = md5('Städte'); # will give you a different hash than MySQL MD5()
#instead use
$md5 = md5(utf8_encode('Städte'));
$r = mysql_query("SELECT *, MD5(`word`) FROM `table_name` WHERE MD5(`word`) LIKE '{$md5}'");
if($r)
while( $row= mysql_fetch_assoc($r) )
print_r($row);
?>
dionyziz at deviantart dot com ¶
5 years ago
Sometimes it's useful to get the actual, binary, md5 digest.
You can use this function for it:
<?php
function md5bin( $target ) {
$md5 = md5( $target );
$ret = '';
for ( $i = 0; $i < 32; $i += 2 ) {
$ret .= chr( hexdec( $md5{ $i + 1 } ) + hexdec( $md5{ $i } ) * 16 );
}
return $ret;
}
?>
marzetti dot marco at NOSPAM dot gmail dot com ¶
7 years ago
The complement of raw2hex
<?php
function hex2raw( $str ){
$chunks = str_split($str, 2);
for( $i = 0; $i < sizeof($chunks); $i++ ) {
$op .= chr( hexdec( $chunks[$i] ) );
}
return $op;
}
?>
Shane Allen ¶
10 years ago
From the documentation on Digest::MD5:
md5($data,...)
This function will concatenate all arguments, calculate the MD5 digest of this "message", and return it in binary form.
md5_hex($data,...)
Same as md5(), but will return the digest in hexadecimal form.
PHP's function returns the digest in hexadecimal form, so my guess is that you're using md5() instead of md5_hex(). I have verified that md5_hex() generates the same string as PHP's md5() function.
(original comment snipped in various places)
>Hexidecimal hashes generated with Perl's Digest::MD5 module WILL
>NOT equal hashes generated with php's md5() function if the input
>text contains any non-alphanumeric characters.
>
>$phphash = md5('pa$$');
>echo "php original hash from text: $phphash";
>echo "md5 hash from perl: " . $myrow['password'];
>
>outputs:
>
>php original hash from text: 0aed5d740d7fab4201e885019a36eace
>hash from perl: c18c9c57cb3658a50de06491a70b75cd
programings at abv dot bg ¶
54 minutes ago
This recursive function allow you to hash something in depth using md5().
<?php
function checksum($what, $depth = 1) {
$depth--;
if (!$depth)
return md5($what);
else
return md5(checksum($what, $depth));
}
?>
The function hashed the previous hash to md5() again and again for number of times and returns the last received hash.
Example usage:
<?php
for ($i = 1; $i <= 10; $i++) {
echo "$i. ".checksum("test", $i)."<br />";
}
?>
It can be used for security purposes.
KB ¶
5 years ago
This is probably well known, but I had a hard time finding a reference to it.
While md5 on a null string returns null, md5 on an EMPTY string does not return null or an empty string. Rather it returns "d41d8cd98f00b204e9800998ecf8427e"
anthonymccuen at yahoo dot com ¶
1 year ago
If your going to hash a password or some other content, you can try the code below.
<?php
function hash_pass($password) {
$appKey = sha1($password);
$appId = 555;
$otherApp = '6cf6e971f7c125615a1ee20510c1c70f'; // simple md5
$appSaltKey = crypt($password);
$getStrLen = strlen($appKey);
$getIdLen = strlen($appId);
$randzStrInt = rand($appId, 999);
if ($appId === 555) {
$go = strlen($appKey);
$other = strlen(crypt(md5(rand($appId, $appId))));
$execute = rand($other, $appId) . "-" . rand($go, $appId) . "-" . rand(strlen(crypt($otherApp)), $appId);
echo $execute . " today is <b>" . $date . "</b>";
}
?>
rick.gaither ¶
7 years ago
This is a nifty function to help in securing your web-forms.
If no argument is passed the function will return an encrypted hex code representing the second it was called. If the same hex code is passed to the function it will return the number of seconds that have elapsed. The php script can then check the time between accessing the web-page and submitting the POST. This thwarts script ran web-form submissions. The program can verify a suitable period has elapsed for expected manual entries. The time check can be from 1 second to about 17 hours.
The function requires the latest PEAR Blowfish Encryption module.
This would go in the form:
<?php print "<input type='hidden' value='" . FormTimer() . "' name='FormCode'>"; ?>
This would go in the main php (post) script:
<?php
$seconds = FormTimer($_POST['FormCode']);
if (($seconds < 10) || ($seconds > 1900)) { die "Your entry time took less than 10 seconds or more than 30 minutes"; }
?>
Function...
<?php
function FormTimer($CodeID="") {
require ('Blowfish.php');
require ('Blowfish/DefaultKey.php');
$key = "Secret^Word";
$bf = new Crypt_Blowfish($key);
$current = substr(sprintf("%d", (time()+1)),-8);
if (!$CodeID) { return bin2hex($bf->encrypt($current)); }
$len = strlen($CodeID); $cValue = -1;
for ($i=0;$i<$len;$i+=2) $Crypt.=chr(hexdec(substr($CodeID,$i,2)));
if ($Crypt) {
$time_called = $bf->decrypt($Crypt);
if ($time_called) { $cValue = (intval($current) - intval($time_called)); }
}
return $cValue;
}
?>
Serge ¶
5 years ago
To convert an MD5 to 22 chars that contains only letters and numeric
<?php
define('HEX_CHARS', '0123456789abcdef');
define('BASE62_CHARS', '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ');
/*********************************************/
function ConvertFromArbitraryBase($Str, $Chars)
/*********************************************/
{
/*
Converts from an arbitrary-base string to a decimal string
*/
if (ereg('^[' . $Chars . ']+$', $Str))
{
$Result = '0';
for ($i=0; $i<strlen($Str); $i++)
{
if ($i != 0) $Result = bcmul($Result, strlen($Chars));
$Result = bcadd($Result, strpos($Chars, $Str[$i]));
}
return $Result;
}
return false;
}
/*******************************************/
function ConvertToArbitraryBase($Str, $Chars)
/*******************************************/
{
/*
Converts from a decimal string to an arbitrary-base string
*/
if (ereg('^[0-9]+$', $Str))
{
$Result = '';
do
{
$Result .= $Chars[bcmod($Str, strlen($Chars))];
$Str = bcdiv($Str, strlen($Chars));
}
while (bccomp($Str, '0') != 0);
return strrev($Result);
}
return false;
}
/**********************/
function CustomMD5($Str)
/**********************/
{
return ConvertToArbitraryBase(ConvertFromArbitraryBase(md5($Str), HEX_CHARS), BASE62_CHARS);
}
?>