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.
md5
(PHP 4, PHP 5, PHP 7)
md5 — Calcula el 'hash' md5 de un string
Advertencia
No se recomienda utilizar esta función para contraseñas seguras debido a la naturaleza rápida de este algoritmo de «hashing». Véase las Preguntas más frecuentes de «hash» de contraseñas para más detalles y el empleo de mejores prácticas.
Descripción
md5
( string
$str
[, bool $raw_output = FALSE
] ) : string
Calcula el hash MD5 de str utilizando el
» Algoritmo MD5 Message-Digest
de RSA Data Security, Inc. y devuelve ese hash.
Parámetros
-
str -
El string.
-
raw_output -
Si se establece el
raw_outputopcional enTRUE, el resumen md5 será devuelto en formato binario sin tratar con una longitud de 16.
Valores devueltos
Devuelve el hash como un número hexadecimal de 32 caracteres.
Ejemplos
Ejemplo #1 Ejemplo de md5()
<?php
$str = 'apple';
if (md5($str) === '1f3870be274f6c49b3e31a0c6728957f') {
echo "Would you like a green or red apple?";
}
?>
Ver también
- md5_file() - Calcula el resumen criptográfico md5 de un archivo dado
- sha1_file() - Calcula el hash sha1 de un archivo
- crc32() - Calcula el polinomio crc32 de una cadena
- sha1() - Calcula el 'hash' sha1 de un string
- hash() - Genera un valor cifrado con base a un string
- crypt() - Hash de cadenas de un sólo sentido
- password_hash() - Crea un hash de contraseña
add a note
User Contributed Notes 8 notes
Ray.Paseur sometimes uses Gmail ¶
6 months ago
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($post_data)) // Post-Data is okay
else // Post-Data is currupted
?>
Ken Guest ¶
1 month ago
Use the strict comparision/identity operator:
php > var_dump(md5('240610708') == md5('QNKCDZO'));
php shell code:1:
bool(true)
php > var_dump(md5('240610708') === md5('QNKCDZO'));
php shell code:1:
bool(false)
php >
because, as mentioned previously, using the equality operator may result in false positives.
hkmaly ¶
1 year ago
Note: Before you get some idea like using md5 with password as way to prevent others tampering with message, read pages "Length extension attack" and "Hash-based message authentication code" on wikipedia. In short, naive constructions can be dangerously insecure. Use hash_hmac if available or reimplement HMAC properly without shortcuts.
Shane Allen ¶
16 years ago
From the documentation on Digest::MD5:
md5($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
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.
dionyziz at deviantart dot com ¶
11 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;
}
?>
