How PHP uses des for encryption and decryption

The code is as follows:

$input-stuff to decrypt

$key-the secret key to use

function Do_mencrypt ($input, $key)

{

$input = Str_replace ("" N "," ", $input);

$input = Str_replace ("T", "", $input);

$input = Str_replace ("R", "", $input);

$key = substr (MD5 ($key), 0, 24);

$TD = Mcrypt_module_open (' TripleDES ', ', ', ' ECB ', ');

$iv = Mcrypt_create_iv (Mcrypt_enc_get_iv_size ($TD), Mcrypt_rand);

Mcrypt_generic_init ($TD, $key, $IV);

$encrypted _data = Mcrypt_generic ($TD, $input);

Mcrypt_generic_deinit ($TD);

Mcrypt_module_close ($TD);

Return Trim (Chop (Base64_encode ($encrypted _data)));

}

$input-stuff to decrypt

$key-the secret key to use

function Do_mdecrypt ($input, $key)

{

$input = Str_replace ("" N "," ", $input);

$input = Str_replace ("T", "", $input);

$input = Str_replace ("R", "", $input);

$input = Trim (Chop (Base64_decode ($input));

$TD = Mcrypt_module_open (' TripleDES ', ', ', ' ECB ', ');

$key = substr (MD5 ($key), 0, 24);

$iv = Mcrypt_create_iv (Mcrypt_enc_get_iv_size ($TD), Mcrypt_rand);

Mcrypt_generic_init ($TD, $key, $IV);

$decrypted _data = Mdecrypt_generic ($TD, $input);

Mcrypt_generic_deinit ($TD);

Mcrypt_module_close ($TD);

Return Trim (Chop ($decrypted _data));

}