6.1 Secure communications and encryption

<?php $username = 'jwilliams'; // just for testing $password = 'topsecrete'; $hashed_password = ???($password); // hash function $query = "insert into Users (Username, Password) values (???, ???)"; // save hashed_password // ... echo $password . ' -> ' . $hashed_password; // just for testing ?> Submit the code to the server to execute PHP code

<?php $username = $_SERVER['PHP_AUTH_USER']; $password = ????; // PHP_AUTH_PW if (????($username) || ????($password) || $username != 'comp3540' || $password != ???) { header('WWW-Authenticate: ??? realm = "My Realm"'); ???('HTTP/1.0 401 Unauthorized'); exit(); } else echo 'Valid username and password<br>'; ?> Submit the code to the server to execute PHP code

<?php // Both sides $cipher = MCRYPT_RIJNDAEL_128; $mode = MCRYPT_MODE_CBC; // cipher block chaining $key = sha1('secretPassword', true); // true => raw_output; ??? // how to use SHA256 instead? // Sender $credit_card_no = '4111 1111 1111 1111'; $ivs = mcrypt_get_iv_size($cipher, $mode); $iv = mcrypt_create_iv($ivs); $data = ???($cipher, $key, $credit_card_no, $mode, $iv); // encrpt it $data = base64_encode($data); // to help the data survive going // through transport layers echo 'Encrypted and encoded data: ' . $data . '<br>'; // transmit $data through the Internet // Receiver $data = ???($data); // decode it $credit_card_no = ???($cipher, $key, $data, $mode, $iv); // decrypt it echo 'Decrypted, i.e., original, data: ' . $credit_card_no . '<br>'; ?> Submit the code to the server to execute PHP code