3DES Data Encryption (3DES/ECB/zeroPadding) PHP <== 7.0.x

Keywords: PHP

1. Introduction to 3DES

_3DES (Triple DES) is an encryption algorithm for the transition from DES to AES (in 1999, NIST designated 3-DES as the transition encryption standard). Its implementation is as follows: Let Ek() and Dk() represent the encryption and decryption process of DES algorithm, K represents the key used by DES algorithm, M represents plaintext, and C represents ciphertext.

The encryption process of 3DES is: C = Ek3 (Dk2 (Ek1 (M))
The decryption process of 3DES is: M = Dk1 (EK2 (Dk3 (C))

_Common "symmetric key" encryption algorithms mainly include DES, 3DES (Triple DES), AES, RC2, RC4, RC5 and Blowfish, etc. I will not mention the implementation of each algorithm here, interested in their own to find.

2. Crypt3Des for Encryption and Decryption

class Crypt3Des
{
    public $key = "";

    function __construct($key)
    {
        $this->key = $key;
    }

    /**
     * data encryption
     * @param string $input
     * @return void
     */
    function encrypt($input)
    {
        $size = mcrypt_get_block_size(MCRYPT_3DES, 'ecb');
        $input = $this->pkcs5_pad($input, $size);
        // $key = str_pad($this->key, 24, '0');
        $key = $this->key;
        $td = mcrypt_module_open(MCRYPT_3DES, '', 'ecb', '');
        $iv = @mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_RAND);
        @mcrypt_generic_init($td, $key, $iv);
        $data = mcrypt_generic($td, $input);
        mcrypt_generic_deinit($td);
        mcrypt_module_close($td);

        $data = base64_encode($data);
        return $data;
    }

    /**
     * data decryption
     * @param string $encrypted
     * @return void
     */
    function decrypt($encrypted)
    { //
        $encrypted = base64_decode($encrypted);
        // $key = str_pad($this->key, 24, '0');
        $key = $this->key;
        $td = mcrypt_module_open(MCRYPT_3DES, '', 'ecb', '');
        $iv = @mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_RAND);
        $ks = mcrypt_enc_get_key_size($td);
        @mcrypt_generic_init($td, $key, $iv);
        $decrypted = mdecrypt_generic($td, $encrypted);
        mcrypt_generic_deinit($td);
        mcrypt_module_close($td);
        $y = $this->pkcs5_unpad($decrypted);
        // return $decrypted;
        return $y;
    }

    /**
     * Encrypted Data Filling
     * @param string $text
     * @param int $blocksize
     * @return void
     */
    function pkcs5_pad($text, $blocksize)
    {
        $pad = $blocksize - (strlen($text) % $blocksize);
        return $text . str_repeat(chr($pad), $pad);
    }

    /**
     * Interception of decrypted data
     * @param string $text
     * @return void
     */
    function pkcs5_unpad($text)
    {
        $pad = ord($text{
            strlen($text) - 1});
        if ($pad > strlen($text)) {
            return false;
        }
        if (strspn($text, chr($pad), strlen($text) - $pad) != $pad) {
            return false;
        }
        return substr($text, 0, -1 * $pad);
    }
}

3. Data Encryption and Decryption

require "Crypt3Des.php";

$key = '1oneSign!@#^*'; // Encryption key, depending on your situation 
// Instantiate encryption classes
$rep = new Crypt3Des($key);
$input = "ILoveMe";
$encrypt_card = $rep->encrypt($input);

echo '<br>';
echo "Original text:" . $input . "<br/>";
echo "Encryption:" . $encrypt_card . "<br/>";
echo "Decrypt:" . $rep->decrypt($encrypt_card) . "<br/>";

Friendship Tips:

_Recommend encryption classes written by others: php_mcrypt (This class applies only to php version 7.1 or below).

Reference resources

Posted by jb60606 on Mon, 07 Oct 2019 05:23:26 -0700

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