mcrypt is deprecated, what is the alternative?

Question

The mcrypt-extension is deprecated will be removed in PHP 7.2 according to the comment posted here. So I am looking for an alternative way to encrypt passwords.

Righ

Answer 1

I was able to translate my Crypto object

• Get a copy of php with mcrypt to decrypt the old data. I went to http://php.net/get/php-7.1.12.tar.gz/from/a/mirror, compiled it, then added the ext/mcrypt extension (configure;make;make install). I think I had to add the extenstion=mcrypt.so line to the php.ini as well. A series of scripts to build intermediate versions of the data with all data unencrypted.

• Build a public and private key for openssl

  openssl genrsa -des3 -out pkey.pem 2048
  (set a password)
  openssl rsa -in pkey.pem -out pkey-pub.pem -outform PEM -pubout
  

• To Encrypt (using public key) use openssl_seal. From what I've read, openssl_encrypt using an RSA key is limited to 11 bytes less than the key length (See http://php.net/manual/en/function.openssl-public-encrypt.php comment by Thomas Horsten)

  $pubKey = openssl_get_publickey(file_get_contents('./pkey-pub.pem'));
  openssl_seal($pwd, $sealed, $ekeys, [ $pubKey ]);
  $encryptedPassword = base64_encode($sealed);
  $key = base64_encode($ekeys[0]);
  

You could probably store the raw binary.

• To Decrypt (using private key)

  $passphrase="passphrase here";
  $privKey = openssl_get_privatekey(file_get_contents('./pkey.pem'), $passphrase);
  // I base64_decode() from my db columns
  openssl_open($encryptedPassword, $plain, $key, $privKey);
  echo "
  Password=$plain
  ";
  

P.S. You can't encrypt the empty string ("")

P.P.S. This is for a password database not for user validation.