php - encrypt and decrypt md5

Question

I am using code $enrypt=md5($pass) and inserting $encrypt to database. I want to find out a way to decrypt them. I tried using a decrypting software but it says the hash should be of exactly 16 bytes. is there any way to decrypt it or to make it a 16 byte md5 hash?

My hash looks like this: c4ca4238a0b923820dcc

Answer 1

As already stated, you cannot decrypt MD5 without attempting something like brute force hacking which is extremely resource intensive, not practical, and unethical.

However you could use something like this to encrypt / decrypt passwords/etc safely:

$input = "SmackFactory";

$encrypted = encryptIt( $input );
$decrypted = decryptIt( $encrypted );

echo $encrypted . '<br />' . $decrypted;

function encryptIt( $q ) {
    $cryptKey  = 'qJB0rGtIn5UB1xG03efyCp';
    $qEncoded      = base64_encode( mcrypt_encrypt( MCRYPT_RIJNDAEL_256, md5( $cryptKey ), $q, MCRYPT_MODE_CBC, md5( md5( $cryptKey ) ) ) );
    return( $qEncoded );
}

function decryptIt( $q ) {
    $cryptKey  = 'qJB0rGtIn5UB1xG03efyCp';
    $qDecoded      = rtrim( mcrypt_decrypt( MCRYPT_RIJNDAEL_256, md5( $cryptKey ), base64_decode( $q ), MCRYPT_MODE_CBC, md5( md5( $cryptKey ) ) ), "");
    return( $qDecoded );
}

Using a encypted method with a salt would be even safer, but this would be a good next step past just using a MD5 hash.