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copied!<p><strong>You should not encrypt passwords, instead you should hash them using an algorithm like bcrypt. <a href="https://stackoverflow.com/a/6337021/2224584">This answer explains how to properly implement password hashing in PHP</a>.</strong> Still, here is how you would encrypt/decrypt:</p> <pre><code>$key = 'password to (en/de)crypt'; $string = ' string to be encrypted '; // note the spaces </code></pre> <p><strong>To Encrypt:</strong></p> <pre><code>$iv = mcrypt_create_iv( mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC), MCRYPT_DEV_URANDOM ); $encrypted = base64_encode( $iv . mcrypt_encrypt( MCRYPT_RIJNDAEL_128, hash('sha256', $key, true), $string, MCRYPT_MODE_CBC, $iv ) ); </code></pre> <p><strong>To Decrypt:</strong></p> <pre><code>$data = base64_decode($encrypted); $iv = substr($data, 0, mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC)); $decrypted = rtrim( mcrypt_decrypt( MCRYPT_RIJNDAEL_128, hash('sha256', $key, true), substr($data, mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC)), MCRYPT_MODE_CBC, $iv ), "\0" ); </code></pre> <hr> <p><strong>Warning</strong>: The above example encrypts information, but it does not authenticate the ciphertext to prevent tampering. <a href="https://paragonie.com/blog/2015/05/using-encryption-and-authentication-correctly" rel="noreferrer">You should <em>not</em> rely on unauthenticated encryption for security</a>, especially since the code as provided is vulnerable to padding oracle attacks.</p> <p>See also:</p> <ul> <li><a href="https://stackoverflow.com/a/30189841/2224584">https://stackoverflow.com/a/30189841/2224584</a></li> <li><a href="https://stackoverflow.com/a/30166085/2224584">https://stackoverflow.com/a/30166085/2224584</a></li> <li><a href="https://stackoverflow.com/a/30159120/2224584">https://stackoverflow.com/a/30159120/2224584</a></li> </ul> <p>Also, don't just use a "password" for an encryption key. <strong>Encryption keys are random strings.</strong></p> <hr> <p><a href="http://3v4l.org/CJfSn" rel="noreferrer">Demo at 3v4l.org</a>:</p> <pre><code>echo 'Encrypted:' . "\n"; var_dump($encrypted); // "m1DSXVlAKJnLm7k3WrVd51omGL/05JJrPluBonO9W+9ohkNuw8rWdJW6NeLNc688=" echo "\n"; echo 'Decrypted:' . "\n"; var_dump($decrypted); // " string to be encrypted " </code></pre>

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