openssl_mcrypt_compatibility_check.php

<?php

$text = 'hkHlLFwvwYoo1IcY';
//$text = 'hkHlLFwvwYoo1I';
//$text = 'hkHlLFwv';
$key = md5('SAMPLE SALT');

$em = encrypt_m($text, $key);
$eo = encrypt_o($text, $key);

echo 'encrypt_m()'.PHP_EOL;
var_dump($em, bin2hex($em));
echo 'encrypt_o()'.PHP_EOL;
var_dump($eo, bin2hex($eo));

$dmm = decrypt_m($em, $key);
$dmo = decrypt_o($em, $key);
$dom = decrypt_m($eo, $key);
$doo = decrypt_o($eo, $key);

echo 'encrypt_m() -> decrpyt_m()'.PHP_EOL;
var_dump($dmm, bin2hex($dmm));
echo 'encrypt_m() -> decrpyt_o()'.PHP_EOL;
var_dump($dmo, bin2hex($dmo));
echo 'encrypt_o() -> decrpyt_m()'.PHP_EOL;
var_dump($dom, bin2hex($dom));
echo 'encrypt_o() -> decrpyt_o()'.PHP_EOL;
var_dump($doo, bin2hex($doo));

function remove_padding($plain_text)
{
    // remove zero padding for mcrypt encrypted text
    $plain_text = rtrim($plain_text, "\0");
    // remove pkcs#7 padding for openssl encrypted text if padding string found
    $pad_ch = substr($plain_text, -1);
    $pad_len = ord($pad_ch);
    $pad_text = str_repeat($pad_ch, $pad_len);
    if (substr_compare($plain_text, $pad_text, -$pad_len) == 0) {
        $plain_text = substr($plain_text, 0, strlen($plain_text) - $pad_len);
    }

    return $plain_text;
}

function encrypt_o($plain_text, $key)
{
    $crypt_text = openssl_encrypt($plain_text, 'DES-ECB', substr($key, 0, 8));

    return $crypt_text;
}
function decrypt_o($crypt_text, $key)
{
    $plain_text = openssl_decrypt($crypt_text, 'DES-ECB', substr($key, 0, 8), OPENSSL_ZERO_PADDING);
    $plain_text = remove_padding($plain_text);

    return $plain_text;
}
function encrypt_m($plain_text, $key)
{
    $td = mcrypt_module_open('des', '', 'ecb', '');
    $key = substr($key, 0, mcrypt_enc_get_key_size($td));
    if (mcrypt_generic_init($td, $key, 'iv_dummy') < 0) {
        return $plain_text;
    }
    $crypt_text = base64_encode(mcrypt_generic($td, $plain_text));
    mcrypt_generic_deinit($td);
    mcrypt_module_close($td);

    return $crypt_text;
}
function decrypt_m($crypt_text, $key)
{
    $td = mcrypt_module_open('des', '', 'ecb', '');
    $key = substr($key, 0, mcrypt_enc_get_key_size($td));
    if (mcrypt_generic_init($td, $key, 'iv_dummy') < 0) {
        return $text;
    }
    $plain_text = mdecrypt_generic($td, base64_decode($crypt_text));
    $plain_text = remove_padding($plain_text);
    mcrypt_generic_deinit($td);
    mcrypt_module_close($td);

    return $plain_text;
}