md5

(PHP 4, PHP 5, PHP 7)

md5Errechnet den MD5-Hash eines Strings

Warnung

Es ist nicht empfohlen, diese Funktion zu verwenden um Passwörter zu hashen, da dieser Passwortalgorithmus relativ schnell ist. Die Seite Password Hashing FAQ enthält weitere Informationen und Best Practices zum Hashen von Passwörtern.

Beschreibung

md5 ( string $str [, bool $raw_output = FALSE ] ) : string

Berechnet den MD5-Hash von str unter Verwendung des » RSA Data Security, Inc. MD5 Message-Digest Algorithm und gibt das Ergebnis zurück.

Parameter-Liste

str

Die Zeichenkette.

raw_output

Wurde der optionale Parameter raw_output mit TRUE angegeben, wird der MD5-Wert im Raw Binary Format mit einer Länge von 16 Zeichen zurückgegeben.

Rückgabewerte

Gibt den Hash als 32 Zeichen lange Hexadezimalzahl zurück.

Beispiele

Beispiel #1 Ein md5()-Beispiel

<?php
$str 
'apple';

if (
md5($str) === '1f3870be274f6c49b3e31a0c6728957f') {
    echo 
"Haetten Sie lieber einen gruenen oder einen roten Apfel?";
}
?>

Siehe auch

  • md5_file() - Berechnet den MD5-Code einer Datei
  • sha1_file() - Berechnet den SHA1-Hash einer Datei
  • crc32() - Berechnet den polynomischen CRC32-Wert eines Strings
  • sha1() - Berechnet den SHA1-Hash eines Strings
  • hash() - Berechnet den Hash einer Nachricht
  • crypt() - Einweg-String-Hashing
  • password_hash() - Erstellt einen Passwort-Hash

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User Contributed Notes 8 notes

up
17
Ray.Paseur sometimes uses Gmail
9 months ago
md5('240610708') == md5('QNKCDZO')

This comparison is true because both md5() hashes start '0e' so PHP type juggling understands these strings to be scientific notation.  By definition, zero raised to any power is zero.
up
7
Ken Guest
4 months ago
Use the strict comparision/identity operator:

php > var_dump(md5('240610708') == md5('QNKCDZO'));
php shell code:1:
bool(true)
php > var_dump(md5('240610708') === md5('QNKCDZO'));
php shell code:1:
bool(false)
php >

because, as mentioned previously, using the equality operator may result in false positives.
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7
radon8472 at radon-software dot net
3 years ago
<?php
   
function raw2hex($rawBinaryChars)
    {
      return =
array_pop(unpack('H*', $rawBinaryChars));
    }
?>

The complement of hey2raw.
You can use to convert from raw md5-format to human-readable format.

This can be usefull to check "Content-Md5" HTTP-Header.

<?php
  $rawMd5   
= base64_decode($_SERVER['HTTP_CONTENT_MD5']);
 
$post_data = file_get_contents("php://input");

  if(
raw2hex($rawMd5) == md5($post_data)) // Post-Data is okay
 
else                                    // Post-Data is currupted
?>
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-7
Shane Allen
16 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
up
-5
hkmaly
1 year ago
Note: Before you get some idea like using md5 with password as way to prevent others tampering with message, read pages "Length extension attack" and "Hash-based message authentication code" on wikipedia. In short, naive constructions can be dangerously insecure. Use hash_hmac if available or reimplement HMAC properly without shortcuts.
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-12
terry _at_ scribendi_com
14 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.
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-25
dionyziz at deviantart dot com
12 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;
}

?>
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-26
John
9 years ago
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.
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