How to encryption data in PHP using base64 with key

Encrypting data in PHP using base64 encoding is not a secure method, as base64 is not an encryption algorithm but rather a method for encoding binary data. For secure encryption, you should use established encryption algorithms like AES (Advanced Encryption Standard) along with a proper key management strategy. Here’s a basic example of encrypting and decrypting data using AES in PHP:

<?php
// Encryption function
function encryptData($data, $key) {
    $cipher = "aes-256-cbc";
    $ivlen = openssl_cipher_iv_length($cipher);
    $iv = openssl_random_pseudo_bytes($ivlen);
    $ciphertext_raw = openssl_encrypt($data, $cipher, $key, $options = OPENSSL_RAW_DATA, $iv);
    $hmac = hash_hmac('sha256', $ciphertext_raw, $key, $as_binary = true);
    $ciphertext = base64_encode($iv . $hmac . $ciphertext_raw);
    return $ciphertext;
}

// Decryption function
function decryptData($ciphertext, $key) {
    $cipher = "aes-256-cbc";
    $c = base64_decode($ciphertext);
    $ivlen = openssl_cipher_iv_length($cipher);
    $iv = substr($c, 0, $ivlen);
    $hmac = substr($c, $ivlen, $sha2len = 32);
    $ciphertext_raw = substr($c, $ivlen + $sha2len);
    $original_plaintext = openssl_decrypt($ciphertext_raw, $cipher, $key, $options = OPENSSL_RAW_DATA, $iv);
    $calcmac = hash_hmac('sha256', $ciphertext_raw, $key, $as_binary = true);
    if (hash_equals($hmac, $calcmac)) {
        return $original_plaintext;
    }
    return false;
}

// Example usage
$key = "YourSecretKey";
$data = "Sensitive information";

// Encrypt data
$encryptedData = encryptData($data, $key);
echo "Encrypted Data: $encryptedData\n";

// Decrypt data
$decryptedData = decryptData($encryptedData, $key);
echo "Decrypted Data: $decryptedData\n";
?>

In this example, AES is used in CBC (Cipher Block Chaining) mode with a randomly generated IV (Initialization Vector) for each encryption. The HMAC (Hash-based Message Authentication Code) is used for integrity verification.

Remember to replace "YourSecretKey" with a strong, secret key and ensure that you handle key management securely. Also, note that this is a simplified example, and in a production environment, you should consider additional security measures and error handling.