4 Simple Ways to Encrypt Decrypt Verify Passwords in PHP

Welcome to a tutorial on the various ways to encrypt, decrypt, and verify passwords in PHP. Since you are reading this guide, I will assume that you are looking for ways to create a more secure system. Yes, I understand that we are web developers and not security experts. But security is a big concern, it does not hurt to at least know how to put a lock on your systems.

Yep, that’s all. But there are a few more ways to secure passwords in PHP – Let us walk through more examples, minus all that complicated Math stuff. Read on!

 

 

TLDR – QUICK SLIDES

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TABLE OF CONTENTS

 

 

 

DUMMY USERS DATABASE

CREATE TABLE `users` (
  `email` varchar(255) NOT NULL,
  `password` varchar(255) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
 
ALTER TABLE `users`
  ADD PRIMARY KEY (`email`);

For this example, we will be working with this database. Very simple. Only has 2 fields – email and password.

 

DUMMY USERS LIBRARY

class User {
  // (A) CONSTRUCTOR - CONNECT TO DATABASE
  private $pdo = null;
  private $stmt = null;
  public $error = null;
  function __construct () {
    $this->pdo = new PDO(
      "mysql:host=".DB_HOST.";dbname=".DB_NAME.";charset=".DB_CHARSET,
      DB_USER, DB_PASSWORD, [
      PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
      PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC
    ]);
  }
 
  // (B) DESTRUCTOR - CLOSE DATABASE CONNECTION
  function __destruct () {
    if ($this->stmt !== null) { $this->stmt = null; }
    if ($this->pdo !== null) { $this->pdo = null; }
  }
 
  // (C) HELPER - RUN QUERY
  function query ($sql, $data=null) : void {
    $this->stmt = $this->pdo->prepare($sql);
    $this->stmt->execute($data);
  }
 
  // (D) ADD/UPDATE USER
  function save ($email, $password) {
    $this->query("REPLACE INTO `users` (`email`, `password`) VALUES (?,?)", [$email, $password]);
    return true;
  }
 
  // (E) GET USER
  function get ($email) {
    $this->query("SELECT * FROM `users` WHERE `email`=?", [$email]);
    return $this->stmt->fetch();
  }
}

// (F) DATABASE SETTINGS - CHANGE TO YOUR OWN!
define("DB_HOST", "localhost");
define("DB_NAME", "test");
define("DB_CHARSET", "utf8");
define("DB_USER", "root");
define("DB_PASSWORD", "");
 
// (G) USER OBJECT
$_USR = new User();

Looks complicated, but is actually pretty straightforward.

• (A, B, G) When $_USR = new User() is created, the constructor connects to the database. The destructor closes the connection.
• (C) query() A helper function to run an SQL query.
• (D) save() Save a user into the database.
• (E) get() Get a user from the database.
• (F) Change the database settings to your own.

 

 

 

METHOD 1) PASSWORD HASH & VERIFY

<?php
// (A) USERS LIBRARY + USER + PASSWORD
require "0b-lib.php";
$email = "job@doe.com";
$password = "ABCD1234";

// (B) ENCRYPT PASSWORD
echo $_USR->save($email, password_hash($password, PASSWORD_DEFAULT))
  ? "OK" : "ERROR" ;

// (C) VERIFY PASSWORD
$user = $_USR->get($email);
echo password_verify($password, $user["password"])
  ? "VALID" : "INVALID" ;

As in the introduction, this is probably one of the easiest and fuss-free ways.

• By default, password_hash() uses the BCRYPT algorithm. You can change the algorithm, check out the full list here.
• Make sure that you have allocated sufficient characters for the password field in the database. At the time of writing, the generated password hash is 60 characters. This may get longer with future algorithm updates.
• Take note that password_hash() is a one-way encryption. Once encrypted, there is no way to easily decrypt.

 

METHOD 2) OPENSSL

// (A) USERS LIBRARY + USER + PASSWORD + SECRET KEY
require "0b-lib.php";
$email = "joe@doe.com";
$password = "ABCD1234";
define ("SECRETKEY", "mysecretkey1234"); // keep in protected config file!
 
// (B) ENCRYPT PASSWORD
echo $_USR->save($email, openssl_encrypt($password, "AES-128-ECB", SECRETKEY))
  ? "OK" : "ERROR" ;

// (C) VERIFY PASSWORD
$user = $_USR->get($email);
echo openssl_decrypt($user["password"], "AES-128-ECB", SECRETKEY) == $password
  ? "VALID" : "INVALID" ;

• To use OpenSSL encryption, you need to enable extension=openssl in php.ini.
• You also need to define a secret key, your own “secret password” – define ("SECRETKEY", "SECRET").
• Don’t lose the secret key. Keep it safe and never expose it publically.
• There are many different cipher methods that we can use with openssl_encrypt(). You can get the full list available on your system using $methods = openssl_get_cipher_methods().

P.S. OpenSSL encryption is two-way encryption. Yes, we can get the password back in cleartext. Maybe this works for some, for the purpose of automated password recovery. But think twice – A compromised secret key will mean someone has access to all the passwords.

P.P.S. OpenSSL can still work for something like a “second password” – Every user keeps their own secret key, to encrypt-decrypt their own sensitive data on the server; We don’t store the users’ secret key, they lose it, and the data is gone for good.

 

 

METHOD 3) CRYPT WITH SALT

// (A) USERS LIBRARY + USER + PASSWORD
require "0b-lib.php";
$email = "jon@doe.com";
$password = "ABCD1234";

// (B) ENCRYPT PASSWORD
// CREDITS : https://www.thecodedeveloper.com/generate-random-alphanumeric-string-with-php/
$salt = substr(base_convert(sha1(uniqid(mt_rand())), 16, 36), 0, 14);
echo $_USR->save($email, crypt($password, $salt))
  ? "OK" : "ERROR" ;

// (C) VERIFY PASSWORD
$user = $_USR->get($email);
echo hash_equals($user["password"], crypt($password, $user["password"]))
  ? "VALID" : "INVALID" ;

Once upon a time in the iron age of PHP, password encryption is not as easy. We manually do our own encryption using crypt() and verification with hash_equals(). To keep the long story short:

• We can use crypt($password) without $salt. But this can be easily cracked with today’s processing power.
• So in simple terms – A “salt” is used to further obfuscate the password, making it slightly harder to crack.
• Yes, crypt() is a one-way hash. There is no such thing as a “decrypt function”.

 

METHOD 4) MD5 & SHA1

// (A) DATABASE LIBRARY + USER + PASSWORD
require "0b-database.php";
$email = "joy@doe.com";
$password = "ABCD1234";
 
// (B) ENCRYPT PASSWORD
// CREDITS : https://www.thecodedeveloper.com/generate-random-alphanumeric-string-with-php/
$salt = substr(base_convert(sha1(uniqid(mt_rand())), 16, 36), 0, 14);
$hash = $salt . md5($salt . $password);
// $hash = $salt . sha1($salt . $password);
echo $_USR->save($email, $hash)
  ? "OK" : "ERROR" ;
 
// (C) VERIFY PASSWORD
$user = $_USR->get($email);
$dbsalt = substr($user["password"], 0, 14);
$dbpass = substr($user["password"], 14);
// echo sha1($dbsalt . $password) == $dbpass
echo md5($dbsalt . $password) == $dbpass
  ? "VALID" : "INVALID" ;

Finally, this is yet another classic password encryption method we use in the Stone Age – By using md5 or sha1. Take note, these are Stone Age methods. With today’s processing power, md5 and sha1 can be easily cracked. So if you want to use it today, at least add some salt in.

 

 

 

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EXAMPLE CODE DOWNLOAD

Click here for the source code on GitHub gist, just click on “download zip” or do a git clone. I have released it under the MIT license, so feel free to build on top of it or use it in your own project.

 

 

WHICH IS THE FASTEST METHOD?

<?php
// (A) PHP PASSWORD HASH
$start = microtime(true);
$clear = "MyPassw@rd!23";
$hash = password_hash($clear, PASSWORD_DEFAULT);
$endA = microtime(true);
$verified = password_verify("MyPassw@rd!23", $hash);
$endB = microtime(true);

$tenc = $endA - $start;
$tdec = $endB - $endA;
$ted = $tenc + $tdec;
echo "PHP password_hash() + password_verify()<br>";
echo "Time taken to encode = " . $tenc . " sec <br>";
echo "Time taken to verify = " . $tdec . " sec <br>";
echo "Total time taken = " . $ted . " sec <br><br>";

// (B) OPENSSL (AES-128-ECB)
$start = microtime(true);
$clear = "MyPassw@rd!23";
$hash = openssl_encrypt($clear, "AES-128-ECB", "mysecretkey1234");
$endA = microtime(true);
$decrypt = openssl_decrypt($hash, "AES-128-ECB", "mysecretkey1234");
$verified = $decrypt == $clear;
$endB = microtime(true);

$tenc = $endA - $start;
$tdec = $endB - $endA;
$ted = $tenc + $tdec;
echo "OpenSSL 128-bit AES<br>";
echo "Time taken to encode = " . $tenc . " sec <br>";
echo "Time taken to verify = " . $tdec . " sec <br>";
echo "Total time taken = " . $ted . " sec <br><br>";

// (C) CRYPT
$start = microtime(true);
$clear = "MyPassw@rd!23";
$salt = substr(base_convert(sha1(uniqid(mt_rand())), 16, 36), 0, 14);
$hash = crypt($clear, $salt);
$endA = microtime(true);
$verified = hash_equals($hash, crypt($clear, $hash));
$endB = microtime(true);

$tenc = $endA - $start;
$tdec = $endB - $endA;
$ted = $tenc + $tdec;
echo "Salted Crypt + Hash Equals<br>";
echo "Time taken to encode = " . $tenc . " sec <br>";
echo "Time taken to verify = " . $tdec . " sec <br>";
echo "Total time taken = " . $ted . " sec <br><br>";

// (D) SALTY MD5 
$start = microtime(true);
$clear = "MyPassw@rd!23";
$salt = substr(base_convert(sha1(uniqid(mt_rand())), 16, 36), 0, 14);
$hash = $salt . md5($salt . $clear);
$endA = microtime(true);
$dbSalt = substr($hash,0,14);
$dbPass = substr($hash,14);
$verified = md5($dbSalt . $clear) == $dbPass;
$endB = microtime(true);

echo "MD5 Salted<br>";
echo "Time taken to encode = " . $tenc . " sec <br>";
echo "Time taken to verify = " . $tdec . " sec <br>";
echo "Total time taken = " . $ted . " sec <br><br>";

Which is the fastest of them all? The results on my dusty PC:

Conclusion, password_hash() and password_verify() is slow. But I will still recommend them for security. Does that split-second even matter? Only if you have a massive website with millions of users.

 

 

QUICK SUMMARY

Method	Security Level	Performance	Notes
Password hash and verify	Medium to high. Depending on the algorithm.	Slow.	One way. Good for protecting passwords, a bit slow though.
OpenSSL encrypt	Low to high. Depending on the algorithm.	Fast.	Two-way encryption. Avoid using for passwords.
Crypt	Low to medium.	Fast.	One way, standard DES. This one is not really secure “out-of-the-box”. Add your own salt to beef it up.
MD5 & SHA1	Very Low	Fast.	Not recommended for passwords. Very easy to crack.

 

USE HTTPS!

No matter which encryption method you use, it is meaningless if you send cleartext passwords over the Internet. So make sure to set up proper HTTPS, it’s FREE these days anyway. The system is only as strong as its weakest link.

 

LINKS & REFERENCES

• Password Hash | Password Verify – PHP
• OpenSSL Encrypt | OpenSSL Decrypt – PHP
• Crypt | Hash Equals – PHP
• MD5 | SHA1 – PHP

 

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