PHP和CGI的数据加密和解密技术：如何保护用户信息

<?php
function encrypt($data, $key) {
    $iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length('AES-256-CBC'));
    $encrypted = openssl_encrypt($data, 'AES-256-CBC', $key, 0, $iv);
    return base64_encode($iv . $encrypted);
}

function decrypt($data, $key) {
    $data = base64_decode($data);
    $iv = substr($data, 0, openssl_cipher_iv_length('AES-256-CBC'));
    $encrypted = substr($data, openssl_cipher_iv_length('AES-256-CBC'));
    return openssl_decrypt($encrypted, 'AES-256-CBC', $key, 0, $iv);
}

$data = 'Hello, World!';
$key = 'mysecretkey';

$encryptedData = encrypt($data, $key);
echo 'Encrypted Data: ' . $encryptedData . '<br>';

$decryptedData = decrypt($encryptedData, $key);
echo 'Decrypted Data: ' . $decryptedData;
?>

<?php
function signData($data, $key) {
    return hash_hmac('sha256', $data, $key);
}

function verifyData($data, $signature, $key) {
    $generatedSignature = hash_hmac('sha256', $data, $key);
    return hash_equals($generatedSignature, $signature);
}

$data = 'Hello, World!';
$key = 'mysecretkey';

$signature = signData($data, $key);
echo 'Signature: ' . $signature . '<br>';

$isValid = verifyData($data, $signature, $key);
echo 'Is Valid: ' . ($isValid ? 'True' : 'False');
?>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

char* encrypt(char* data, char* key) {
    // Encryption logic here
    return encryptedData;
}

char* decrypt(char* data, char* key) {
    // Decryption logic here
    return decryptedData;
}

int main() {
    char* data = "Hello, World!";
    char* key = "mysecretkey";

    char* encryptedData = encrypt(data, key);
    printf("Encrypted Data: %s
", encryptedData);

    char* decryptedData = decrypt(encryptedData, key);
    printf("Decrypted Data: %s
", decryptedData);

    return 0;
}