£ £ £ £ <?php
£ £ £ £ // Designate string to be encrypted
£ £ £ £ $string = "Applied Cryptography, by Bruce Schneier, is
£ £ £ £ a wonderful cryptography reference.";

£ £ £ £ // Encryption/decryption key
£ £ £ £ $key = "Four score and twenty years ago";

£ £ £ £ // Encryption Algorithm
£ £ £ £ $cipher_alg = MCRYPT_RIJNDAEL_128;

£ £ £ £ // Create the initialization vector for added security.
£ £ £ £ $iv = mcrypt_create_iv(mcrypt_get_iv_size($cipher_alg,
£ £ £ £ MCRYPT_MODE_ECB), MCRYPT_RAND);

£ £ £ £ // Output original string
£ £ £ £ print "Original string: $string <P>";

£ £ £ £ // Encrypt $string
£ £ £ £ $encrypted_string = mcrypt_encrypt($cipher_alg, $key,
£ £ £ £ $string, MCRYPT_MODE_CBC, $iv);

£ £ £ £ // Convert to hexadecimal and output to browser
£ £ £ £ print "Encrypted string: ".bin2hex($encrypted_string)." <P>";
£ £ £ £ $decrypted_string = mcrypt_decrypt($cipher_alg, $key,
£ £ £ £ $encrypted_string, MCRYPT_MODE_CBC, $iv);

£ £ £ £ print "Decrypted string: $decrypted_string";
£ £ £ £ ?>