在开始之前，请确保你已经将 BouncyCastle 的 NuGet 包安装到你的项目中。你可以通过 NuGet 包管理器控制台或 Visual Studio 中的 NuGet 包管理器进行安装。

Install-Package BouncyCastle

接下来，我将演示如何使用 BouncyCastle 实现一些常见的加解密操作。

1. AES 加解密

using System; using System.Text; using Org.BouncyCastle.Crypto; using Org.BouncyCastle.Crypto.Engines; using Org.BouncyCastle.Crypto.Modes; using Org.BouncyCastle.Crypto.Parameters;  public class AesExample {     public static byte[] Encrypt(string plaintext, byte[] key, byte[] iv)     {         CipherEngine engine = new CipherEngine();         CipherParameters keyParam = new KeyParameter(key);         ParametersWithIV keyParamWithIV = new ParametersWithIV(keyParam, iv);          engine.Init(true, keyParamWithIV);          byte[] input = Encoding.UTF8.GetBytes(plaintext);         byte[] output = new byte[engine.GetOutputSize(input.Length)];          int len = engine.ProcessBytes(input, 0, input.Length, output, 0);         engine.DoFinal(output, len);          return output;     }      public static string Decrypt(byte[] ciphertext, byte[] key, byte[] iv)     {         CipherEngine engine = new CipherEngine();         CipherParameters keyParam = new KeyParameter(key);         ParametersWithIV keyParamWithIV = new ParametersWithIV(keyParam, iv);          engine.Init(false, keyParamWithIV);          byte[] output = new byte[engine.GetOutputSize(ciphertext.Length)];          int len = engine.ProcessBytes(ciphertext, 0, ciphertext.Length, output, 0);         engine.DoFinal(output, len);          return Encoding.UTF8.GetString(output);     } }  // 示例用法 byte[] aesKey = new byte[16]; // AES 128-bit key byte[] aesIV = new byte[16];  // AES 128-bit IV string plaintext = "Hello, BouncyCastle!";  byte[] ciphertext = AesExample.Encrypt(plaintext, aesKey, aesIV); string decryptedText = AesExample.Decrypt(ciphertext, aesKey, aesIV);  Console.WriteLine($"Plaintext: {plaintext}"); Console.WriteLine($"Ciphertext: {Convert.ToBase64String(ciphertext)}"); Console.WriteLine($"Decrypted Text: {decryptedText}");

2. RSA 加解密

using System; using System.Text; using Org.BouncyCastle.Crypto; using Org.BouncyCastle.Crypto.Encodings; using Org.BouncyCastle.Crypto.Engines; using Org.BouncyCastle.Crypto.Parameters; using Org.BouncyCastle.Security;  public class RsaExample {     public static byte[] Encrypt(string plaintext, AsymmetricKeyParameter publicKey)     {         CipherEngine engine = new CipherEngine();         engine.Init(true, publicKey);          byte[] input = Encoding.UTF8.GetBytes(plaintext);         byte[] output = engine.ProcessBytes(input, 0, input.Length);          return output;     }      public static string Decrypt(byte[] ciphertext, AsymmetricKeyParameter privateKey)     {         CipherEngine engine = new CipherEngine();         engine.Init(false, privateKey);          byte[] output = engine.ProcessBytes(ciphertext, 0, ciphertext.Length);          return Encoding.UTF8.GetString(output);     } }  // 示例用法 RsaKeyPairGenerator rsaKeyPairGen = GeneratorUtilities.GetKeyPairGenerator("RSA"); rsaKeyPairGen.Init(new KeyGenerationParameters(new SecureRandom(), 2048)); // 2048-bit key size AsymmetricCipherKeyPair keyPair = rsaKeyPairGen.GenerateKeyPair();  AsymmetricKeyParameter publicKey = keyPair.Public; AsymmetricKeyParameter privateKey = keyPair.Private;  string plaintext = "Hello, BouncyCastle!";  byte[] ciphertext = RsaExample.Encrypt(plaintext, publicKey); string decryptedText = RsaExample.Decrypt(ciphertext, privateKey);  Console.WriteLine($"Plaintext: {plaintext}"); Console.WriteLine($"Ciphertext: {Convert.ToBase64String(ciphertext)}"); Console.WriteLine($"Decrypted Text: {decryptedText}");

3. MD5、SHA1、SHA256、SHA384、SHA512

using System; using System.Security.Cryptography; using System.Text; using Org.BouncyCastle.Crypto.Digests;  public class HashExample {     public static string ComputeMD5(string input)     {         MD5 md5 = MD5.Create();         byte[] hashBytes = md5.ComputeHash(Encoding.UTF8.GetBytes(input));         return BitConverter.ToString(hashBytes).Replace("-", "").ToLower();     }      public static string ComputeSHA1(string input)     {         SHA1 sha1 = SHA1.Create();         byte[] hashBytes = sha1.ComputeHash(Encoding.UTF8.GetBytes(input));         return BitConverter.ToString(hashBytes).Replace("-", "").ToLower();     }      public static string ComputeSHA256(string input)     {         Sha256Digest sha256 = new Sha256Digest();         byte[] inputBytes = Encoding.UTF8.GetBytes(input);         sha256.BlockUpdate(inputBytes, 0, inputBytes.Length);          byte[] hashBytes = new byte[sha256.GetDigestSize()];         sha256.DoFinal(hashBytes, 0);          return BitConverter.ToString(hashBytes).Replace("-", "").ToLower();     }      public static string ComputeSHA384(string input)     {         Sha384Digest sha384 = new Sha384Digest();         byte[] inputBytes = Encoding.UTF8.GetBytes(input);         sha384.BlockUpdate(inputBytes, 0, inputBytes.Length);          byte[] hashBytes = new byte[sha384.GetDigestSize()];         sha384.DoFinal(hashBytes, 0);          return BitConverter.ToString(hashBytes).Replace("-", "").ToLower();     }      public static string ComputeSHA512(string input)     {         Sha512Digest sha512 = new Sha512Digest();         byte[] inputBytes = Encoding.UTF8.GetBytes(input);         sha512.BlockUpdate(inputBytes, 0, inputBytes.Length);          byte[] hashBytes = new byte[sha512.GetDigestSize()];         sha512.DoFinal(hashBytes, 0);          return BitConverter.ToString(hashBytes).Replace("-", "").ToLower();     } }  // 示例用法 string input = "Hello, BouncyCastle!"; Console.WriteLine($"MD5: {HashExample.ComputeMD5(input)}"); Console.WriteLine($"SHA1: {HashExample.ComputeSHA1(input)}"); Console.WriteLine($"SHA256: {HashExample.ComputeSHA256(input)}"); Console.WriteLine($"SHA384: {HashExample.ComputeSHA384(input)}"); Console.WriteLine($"SHA512: {HashExample.ComputeSHA512(input)}");

这些示例展示了在 .NET 下使用 BouncyCastle 实现 AES、RSA、MD5、SHA1、SHA256、SHA384、SHA512 加解密的基本操作。

具体的实现细节可能根据 BouncyCastle 版本略有变化，建议查阅 BouncyCastle 的官方文档以获取最新信息。