Ejemplos

Mcrypt puede ser utilizada para el cifrado y descifrado empleando los cifradores arriba mencionados. Si se enlazó con libmcrypt-2.2.x, los cuatro comandos importantes de mcrypt (mcrypt_cfb(), mcrypt_cbc(), mcrypt_ecb(), y mcrypt_ofb()) puede operar en ambos modos, los cuales son denominados MCRYPT_ENCRYPT y MCRYPT_DECRYPT, respectivamente.

Si se enlazó con libmcrypt 2.4.x o 2.5.x, estas funciones todavía están disponibles, pero es recomendable que se utilicen las funciones avanzadas.

Ejemplo #1 Cifrar un valor de entrada con AES con una clave de 256 bits bajo 2.4.x y superiores en modo CBC

<?php
    $clave 
hash('sha256''esta es una clave secreta'true);
    
$entrada "Encontrémonos a las 9 en punto en el escondite.";

    
$td mcrypt_module_open('rijndael-128''''cbc''');
    
$iv mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_DEV_URANDOM);
    
mcrypt_generic_init($td$clave$iv);
    
$datos_encriptados mcrypt_generic($td$entrada);
    
mcrypt_generic_deinit($td);
    
mcrypt_module_close($td);
?>
Este ejemplo proporcionará los datos encriptados como un string en $datos_encriptados. Para un ejemplo completo, véase mcrypt_module_open().

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User Contributed Notes 2 notes

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3
jizz @ Nowhere
8 years ago
Ok after having a problem using triple des with .net/visual basic with php I think this could help someone:

Visual Basic 9 with .net 2.0
Encrypting as a stream into the IO/Memory as bytes
Then they get converted back after encryption

I wanted to use base64 encoding to store the VB encryption
The problem I found was ...

I could En/Decrypt within VB and PHP just fine
But when I tried to encrypt one in VB and decrypt in PHP
I got the wrong values with the mcrypt function alone

I found that at least with VB9 that the stream encryption uses a UTF char that is the value for how many missing bytes left in the 8 bit stream.

So if you encrypt 1234 it will add chr(4) four times (the amount of missing bytes)
In php use chr otherwise most browsers/client cant read it.
Im not good at explaining things but the php code I figured out is below.

It will find the missing bytes on input as visual basic does
and replace as needed. For both encryption and decryption.

Example is triple_des and cbc with self key and iv for storing in base64

$key = "E4HD9h4DhS23DYfhHemkS3Nf";// 24 bit Key
$iv = "fYfhHeDm";// 8 bit IV
$input = "Text to encrypt";// text to encrypt
$bit_check=8;// bit amount for diff algor.

$str= encrypt($input,$key,$iv,$bit_check);
echo "Start: $input - Excrypted: $str - Decrypted: ".decrypt($str,$key,$iv,$bit_check);

function encrypt($text,$key,$iv,$bit_check) {
$text_num =str_split($text,$bit_check);
$text_num = $bit_check-strlen($text_num[count($text_num)-1]);
for ($i=0;$i<$text_num; $i++) {$text = $text . chr($text_num);}
$cipher = mcrypt_module_open(MCRYPT_TRIPLEDES,'','cbc','');
mcrypt_generic_init($cipher, $key, $iv);
$decrypted = mcrypt_generic($cipher,$text);
mcrypt_generic_deinit($cipher);
return base64_encode($decrypted);
}

function decrypt($encrypted_text,$key,$iv,$bit_check){
$cipher = mcrypt_module_open(MCRYPT_TRIPLEDES,'','cbc','');
mcrypt_generic_init($cipher, $key, $iv);
$decrypted = mdecrypt_generic($cipher,base64_decode($encrypted_text));
mcrypt_generic_deinit($cipher);
$last_char=substr($decrypted,-1);
for($i=0;$i<$bit_check-1; $i++){
    if(chr($i)==$last_char){
       
       
       
        $decrypted=substr($decrypted,0,strlen($decrypted)-$i);
        break;
    }
}
return $decrypted;
}
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0
ivoras at gmail dot com
6 years ago
Note that there can be standard padding in block modes:

http://www.di-mgt.com.au/cryptopad.html
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