37 lines
1.3 KiB
PHP
37 lines
1.3 KiB
PHP
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<?php
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require_once('Crypto.php');
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try {
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$key = Crypto::CreateNewRandomKey();
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// WARNING: Do NOT encode $key with bin2hex() or base64_encode(),
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// they may leak the key to the attacker through side channels.
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} catch (CryptoTestFailedException $ex) {
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die('Cannot safely create a key');
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} catch (CannotPerformOperationException $ex) {
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die('Cannot safely create a key');
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}
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$message = "ATTACK AT DAWN";
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try {
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$ciphertext = Crypto::Encrypt($message, $key);
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} catch (CryptoTestFailedException $ex) {
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die('Cannot safely perform encryption');
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} catch (CannotPerformOperationException $ex) {
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die('Cannot safely perform decryption');
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}
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try {
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$decrypted = Crypto::Decrypt($ciphertext, $key);
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} catch (InvalidCiphertextException $ex) { // VERY IMPORTANT
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// Either:
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// 1. The ciphertext was modified by the attacker,
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// 2. The key is wrong, or
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// 3. $ciphertext is not a valid ciphertext or was corrupted.
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// Assume the worst.
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die('DANGER! DANGER! The ciphertext has been tampered with!');
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} catch (CryptoTestFailedException $ex) {
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die('Cannot safely perform encryption');
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} catch (CannotPerformOperationException $ex) {
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die('Cannot safely perform decryption');
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}
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?>
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