How to use PHP functions for data encryption and decryption?

How to use PHP functions for data encryption and decryption?

Overview
Data encryption and decryption is an important means of protecting sensitive information. In PHP, we can use some functions to implement data encryption and decryption operations. This article will introduce how to use PHP functions for data encryption and decryption, and provide corresponding code examples.

1. Use base64_encode and base64_decode functions for simple encryption and decryption
   The base64_encode function can encode a string into base64 format, and the base64_decode function can decode the base64 format into the original string. This encryption method is relatively simple and is mainly used for simple text encryption.

<?php
    // 加密函数
    function encrypt($data){
        $encrypt_data = base64_encode($data);
        return $encrypt_data;
    }
    
    // 解密函数
    function decrypt($encrypt_data){
        $data = base64_decode($encrypt_data);
        return $data;
    }
    
    // 测试加密解密
    $original_data = 'Hello, World!';
    $encrypted_data = encrypt($original_data);
    $decrypted_data = decrypt($encrypted_data);
    
    echo "Original Data: " . $original_data . "<br>";
    echo "Encrypted Data: " . $encrypted_data . "<br>";
    echo "Decrypted Data: " . $decrypted_data . "<br>";
?>

2. Use mcrypt_encrypt and mcrypt_decrypt functions for advanced encryption and decryption
   The mcrypt_encrypt function and mcrypt_decrypt function provide more advanced encryption and decryption functions. Before using these two functions, you need to ensure that the mcrypt extension is installed.

<?php
    // 加密函数
    function encrypt($data, $key){
        $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);
        $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
        $encrypted_data = mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $key, $data, MCRYPT_MODE_CBC, $iv);
        $encrypted_data = $iv . $encrypted_data;
        return base64_encode($encrypted_data);
    }
    
    // 解密函数
    function decrypt($encrypted_data, $key){
        $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);
        $encrypted_data = base64_decode($encrypted_data);
        $iv = substr($encrypted_data, 0, $iv_size);
        $encrypted_data = substr($encrypted_data, $iv_size);
        $data = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, $encrypted_data, MCRYPT_MODE_CBC, $iv);
        return rtrim($data, "");
    }
    
    // 测试加密解密
    $original_data = 'Hello, World!';
    $key = 'my-secret-key';
    $encrypted_data = encrypt($original_data, $key);
    $decrypted_data = decrypt($encrypted_data, $key);
    
    echo "Original Data: " . $original_data . "<br>";
    echo "Encrypted Data: " . $encrypted_data . "<br>";
    echo "Decrypted Data: " . $decrypted_data . "<br>";
?>

Summary
This article introduces the method of using PHP functions for data encryption and decryption, and provides corresponding code examples. Encryption and decryption are important means of protecting sensitive data. It is important to choose appropriate encryption methods and algorithms to avoid information leakage. Using these functions can help us store and transmit sensitive data securely.

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