C#实现简单的文件加密与解密方式

C#实现简单的文件加密与解密方式攻略

介绍

本文详细讲解如何使用C#语言实现简单的文件加密与解密方式。文件加密是数据保护的一种方法，通过对敏感文件进行加密，确保在未授权的情况下无法访问和解读文件内容。本文讲解将使用对称加密算法 AES 实现文件加密与解密。

实现过程

1. 导入 System.Security.Cryptography 命名空间。该命名空间提供了对称加密算法的支持。

using System.Security.Cryptography;

1. 创建一个加解密类。

public class AesEncryption
{
    // 加密密钥
    private static readonly byte[] key = Encoding.UTF8.GetBytes("0123456789abcdefghijklmnopqrstuvwxyz");

    // 初始化向量
    private static readonly byte[] iv = Encoding.UTF8.GetBytes("9876543210zyxwvutsrqponmlkjihgfedcba");

    // 加密方法
    public static void EncryptFile(string inputFile, string outputFile)
    {
        using (AesCryptoServiceProvider aes = new AesCryptoServiceProvider())
        {
            aes.Key = key;
            aes.IV = iv;

            using (FileStream fsInput = new FileStream(inputFile, FileMode.Open, FileAccess.Read))
            {
                using (FileStream fsOutput = new FileStream(outputFile, FileMode.Create, FileAccess.Write))
                {
                    using (CryptoStream cryptoStream = new CryptoStream(fsOutput, aes.CreateEncryptor(), CryptoStreamMode.Write))
                    {
                        byte[] buffer = new byte[4096];
                        int read = 0;

                        while ((read = fsInput.Read(buffer, 0, buffer.Length)) > 0)
                        {
                            cryptoStream.Write(buffer, 0, read);
                        }

                        cryptoStream.FlushFinalBlock();
                    }
                }
            }
        }
    }

    // 解密方法
    public static void DecryptFile(string inputFile, string outputFile)
    {
        using (AesCryptoServiceProvider aes = new AesCryptoServiceProvider())
        {
            aes.Key = key;
            aes.IV = iv;

            using (FileStream fsInput = new FileStream(inputFile, FileMode.Open, FileAccess.Read))
            {
                using (FileStream fsOutput = new FileStream(outputFile, FileMode.Create, FileAccess.Write))
                {
                    using (CryptoStream cryptoStream = new CryptoStream(fsOutput, aes.CreateDecryptor(), CryptoStreamMode.Write))
                    {
                        byte[] buffer = new byte[4096];
                        int read = 0;

                        while ((read = fsInput.Read(buffer, 0, buffer.Length)) > 0)
                        {
                            cryptoStream.Write(buffer, 0, read);
                        }

                        cryptoStream.FlushFinalBlock();
                    }
                }
            }
        }
    }
}

1. 调用加密与解密方法。

string inputFile = "path\\to\\input\\file.txt";
string encryptedFile = "path\\to\\encrypted\\file.enc";
string decryptedFile = "path\\to\\decrypted\\file.txt";

// 文件加密
AesEncryption.EncryptFile(inputFile, encryptedFile);

// 文件解密
AesEncryption.DecryptFile(encryptedFile, decryptedFile);

示例

示例1

以下示例将读取 inputfile.txt 中的文本内容，使用 AES 对称加密算法对文本内容进行加密，将加密结果输出到 encryptedfile.txt 中，然后再将 encryptedfile.txt 文件进行解密，并输出到 decryptedfile.txt 中。

using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;

public class AesEncryption
{
    // 加密密钥
    private static readonly byte[] key = Encoding.UTF8.GetBytes("0123456789abcdefghijklmnopqrstuvwxyz");

    // 初始化向量
    private static readonly byte[] iv = Encoding.UTF8.GetBytes("9876543210zyxwvutsrqponmlkjihgfedcba");

    // 加密方法
    public static void EncryptFile(string inputFile, string outputFile)
    {
        using (AesCryptoServiceProvider aes = new AesCryptoServiceProvider())
        {
            aes.Key = key;
            aes.IV = iv;

            using (FileStream fsInput = new FileStream(inputFile, FileMode.Open, FileAccess.Read))
            {
                using (FileStream fsOutput = new FileStream(outputFile, FileMode.Create, FileAccess.Write))
                {
                    using (CryptoStream cryptoStream = new CryptoStream(fsOutput, aes.CreateEncryptor(), CryptoStreamMode.Write))
                    {
                        byte[] buffer = new byte[4096];
                        int read = 0;

                        while ((read = fsInput.Read(buffer, 0, buffer.Length)) > 0)
                        {
                            cryptoStream.Write(buffer, 0, read);
                        }

                        cryptoStream.FlushFinalBlock();
                    }
                }
            }
        }
    }

    // 解密方法
    public static void DecryptFile(string inputFile, string outputFile)
    {
        using (AesCryptoServiceProvider aes = new AesCryptoServiceProvider())
        {
            aes.Key = key;
            aes.IV = iv;

            using (FileStream fsInput = new FileStream(inputFile, FileMode.Open, FileAccess.Read))
            {
                using (FileStream fsOutput = new FileStream(outputFile, FileMode.Create, FileAccess.Write))
                {
                    using (CryptoStream cryptoStream = new CryptoStream(fsOutput, aes.CreateDecryptor(), CryptoStreamMode.Write))
                    {
                        byte[] buffer = new byte[4096];
                        int read = 0;

                        while ((read = fsInput.Read(buffer, 0, buffer.Length)) > 0)
                        {
                            cryptoStream.Write(buffer, 0, read);
                        }

                        cryptoStream.FlushFinalBlock();
                    }
                }
            }
        }
    }
}

public class Program
{
    static void Main(string[] args)
    {
        string inputFile = @"C:\data\inputfile.txt";
        string encryptedFile = @"C:\data\encryptedfile.enc";
        string decryptedFile = @"C:\data\decryptedfile.txt";

        // 文件加密
        AesEncryption.EncryptFile(inputFile, encryptedFile);

        // 文件解密
        AesEncryption.DecryptFile(encryptedFile, decryptedFile);

        Console.WriteLine("File encryption and decryption has been completed.");
    }
}

示例2

以下示例将读取指定路径下的 inputfile.jpg图片，使用 AES 对称加密算法对图片进行加密，并将其输出到 encryptedfile.jpg 中，再将 encryptedfile.jpg 文件进行解密，并输出到 decryptedfile.jpg 中。

public class AesEncryption
{
    // 加密密钥
    private static readonly byte[] key = Encoding.UTF8.GetBytes("0123456789abcdefghijklmnopqrstuvwxyz");

    // 初始化向量
    private static readonly byte[] iv = Encoding.UTF8.GetBytes("9876543210zyxwvutsrqponmlkjihgfedcba");

    // 加密方法
    public static void EncryptFile(string inputFile, string outputFile)
    {
        using (AesCryptoServiceProvider aes = new AesCryptoServiceProvider())
        {
            aes.Key = key;
            aes.IV = iv;

            using (FileStream fsInput = new FileStream(inputFile, FileMode.Open, FileAccess.Read))
            {
                using (FileStream fsOutput = new FileStream(outputFile, FileMode.Create, FileAccess.Write))
                {
                    using (CryptoStream cryptoStream = new CryptoStream(fsOutput, aes.CreateEncryptor(), CryptoStreamMode.Write))
                    {
                        byte[] buffer = new byte[4096];
                        int read = 0;

                        while ((read = fsInput.Read(buffer, 0, buffer.Length)) > 0)
                        {
                            cryptoStream.Write(buffer, 0, read);
                        }

                        cryptoStream.FlushFinalBlock();
                    }
                }
            }
        }
    }

    // 解密方法
    public static void DecryptFile(string inputFile, string outputFile)
    {
        using (AesCryptoServiceProvider aes = new AesCryptoServiceProvider())
        {
            aes.Key = key;
            aes.IV = iv;

            using (FileStream fsInput = new FileStream(inputFile, FileMode.Open, FileAccess.Read))
            {
                using (FileStream fsOutput = new FileStream(outputFile, FileMode.Create, FileAccess.Write))
                {
                    using (CryptoStream cryptoStream = new CryptoStream(fsOutput, aes.CreateDecryptor(), CryptoStreamMode.Write))
                    {
                        byte[] buffer = new byte[4096];
                        int read = 0;

                        while ((read = fsInput.Read(buffer, 0, buffer.Length)) > 0)
                        {
                            cryptoStream.Write(buffer, 0, read);
                        }

                        cryptoStream.FlushFinalBlock();
                    }
                }
            }
        }
    }
}

public class Program
{
    static void Main(string[] args)
    {
        string inputFile = @"C:\data\inputfile.jpg";
        string encryptedFile = @"C:\data\encryptedfile.jpg";
        string decryptedFile = @"C:\data\decryptedfile.jpg";

        // 文件加密
        AesEncryption.EncryptFile(inputFile, encryptedFile);

        // 文件解密
        AesEncryption.DecryptFile(encryptedFile, decryptedFile);

        Console.WriteLine("File encryption and decryption has been completed.");
    }
}

结论

本文以 AES 对称加密算法为例，讲解了 C# 实现简单的文件加密与解密方式攻略。读者可以在实际应用中根据需要，选择不同的加密算法实现更加安全的文件加密功能。