.NET Core加解密实战系列之——RSA非对称加密算法

简介

加解密现状，编写此项目的背景：

需要考虑系统环境兼容性问题（Linux、Windows）
语言互通问题（如C#、Java）
网上资料版本不一、不全面
.NET官方库密码算法提供不全面，很难针对其他语言（Java）进行适配

本系列文章主要介绍如何结合BouncyCastle在 .NET Core 中使用非对称加密算法、编码算法、哈希算法、对称加密算法、国密算法等一系列算法，内容篇幅代码居多（加解密算法相关的原理知识网上有很多，因此不过多介绍）。如有错误之处，还请大家批评指正。

本系列代码项目地址：https://github.com/fuluteam/ICH.BouncyCastle.git

功能依赖

BouncyCastle（https://www.bouncycastle.org/csharp）是一个开放源码的轻量级密码术包；它支持大量的密码术算法，它提供了很多.NET Core标准库没有的算法。

支持.NET 4，.NET Standard 1.0-2.0，WP，Silverlight，MonoAndroid，Xamarin.iOS，.NET Core

功能	依赖
Portable.BouncyCastle	Portable.BouncyCastle • 1.8.5

生成RSA秘钥

PKCS1格式

/// <summary>/// PKCS1（非Java适用）/// </summary>/// <param name="keySize">密钥长度”一般只是指模值的位长度。目前主流可选值：1024、2048、3072、4096...</param>/// <param name="format">PEM格式</param>/// <returns></returns>public RSAKeyParameter Pkcs1(int keySize, bool format=false){var keyGenerator = GeneratorUtilities.GetKeyPairGenerator("RSA");keyGenerator.Init(new KeyGenerationParameters(new SecureRandom(), keySize));var keyPair = keyGenerator.GenerateKeyPair();var subjectPublicKeyInfo = SubjectPublicKeyInfoFactory.CreateSubjectPublicKeyInfo(keyPair.Public);var privateKeyInfo = PrivateKeyInfoFactory.CreatePrivateKeyInfo(keyPair.Private);if (!format){return new RSAKeyParameter{PrivateKey = Base64.ToBase64String(privateKeyInfo.ParsePrivateKey().GetEncoded()),PublicKey = Base64.ToBase64String(subjectPublicKeyInfo.GetEncoded())};}var rsaKey = new RSAKeyParameter();using (var sw = new StringWriter()){var pWrt = new PemWriter(sw);pWrt.WriteObject(keyPair.Private);pWrt.Writer.Close();rsaKey.PrivateKey = sw.ToString();}using (var sw = new StringWriter()){var pWrt = new PemWriter(sw);pWrt.WriteObject(keyPair.Public);pWrt.Writer.Close();rsaKey.PublicKey = sw.ToString();}return rsaKey;}

PKCS8格式

/// <summary>/// PKCS8（JAVA适用）/// </summary>/// <param name="keySize">密钥长度”一般只是指模值的位长度。目前主流可选值：1024、2048、3072、4096...</param>/// <param name="format">PEM格式</param>/// <returns></returns>public RSAKeyParameter Pkcs8(int keySize, bool format=false){var keyGenerator = GeneratorUtilities.GetKeyPairGenerator("RSA");keyGenerator.Init(new KeyGenerationParameters(new SecureRandom(), keySize));var keyPair = keyGenerator.GenerateKeyPair();var subjectPublicKeyInfo = SubjectPublicKeyInfoFactory.CreateSubjectPublicKeyInfo(keyPair.Public);var privateKeyInfo = PrivateKeyInfoFactory.CreatePrivateKeyInfo(keyPair.Private);if (!format){return new RSAKeyParameter{PrivateKey = Base64.ToBase64String(privateKeyInfo.GetEncoded()),PublicKey = Base64.ToBase64String(subjectPublicKeyInfo.GetEncoded())};}var rsaKey = new RSAKeyParameter();using (var sw = new StringWriter()){var pWrt = new PemWriter(sw);var pkcs8 = new Pkcs8Generator(keyPair.Private);pWrt.WriteObject(pkcs8);pWrt.Writer.Close();rsaKey.PrivateKey = sw.ToString();}using (var sw = new StringWriter()){var pWrt = new PemWriter(sw);pWrt.WriteObject(keyPair.Public);pWrt.Writer.Close();rsaKey.PublicKey = sw.ToString();}return rsaKey;}

私钥操作

PKCS1与PKCS8格式互转

仅私钥有PKCS1和PKCS8之分，公钥无格式区别。

/// <summary>/// Pkcs1>>Pkcs8/// </summary>/// <param name="privateKey">Pkcs1私钥</param>/// <param name="format">是否转PEM格式</param>/// <returns></returns>public static string PrivateKeyPkcs1ToPkcs8(string privateKey, bool format = false){var akp = RSAUtilities.GetAsymmetricKeyParameterFormPrivateKey(privateKey);if (format){var sw = new StringWriter();var pWrt = new PemWriter(sw);var pkcs8 = new Pkcs8Generator(akp);pWrt.WriteObject(pkcs8);pWrt.Writer.Close();return sw.ToString();}else{var privateKeyInfo = PrivateKeyInfoFactory.CreatePrivateKeyInfo(akp);return Base64.ToBase64String(privateKeyInfo.GetEncoded());}}

/// <summary>/// Pkcs8>>Pkcs1/// </summary>/// <param name="privateKey">Pkcs8私钥</param>/// <param name="format">是否转PEM格式</param>/// <returns></returns>public static string PrivateKeyPkcs8ToPkcs1(string privateKey, bool format = false){var akp = RSAUtilities.GetAsymmetricKeyParameterFormAsn1PrivateKey(privateKey);if (format){var sw = new StringWriter();var pWrt = new PemWriter(sw);pWrt.WriteObject(akp);pWrt.Writer.Close();return sw.ToString();}else{var privateKeyInfo = PrivateKeyInfoFactory.CreatePrivateKeyInfo(akp);return Base64.ToBase64String(privateKeyInfo.ParsePrivateKey().GetEncoded());}}

PKCS1与PKCS8私钥中提取公钥

/// <summary>/// 从Pkcs1私钥中提取公钥/// </summary>/// <param name="privateKey">Pkcs1私钥</param>/// <returns></returns>public static string GetPublicKeyFromPrivateKeyPkcs1(string privateKey){var instance = RsaPrivateKeyStructure.GetInstance(Base64.Decode(privateKey));var publicParameter = (AsymmetricKeyParameter)new RsaKeyParameters(false, instance.Modulus,instance.PublicExponent);var privateParameter = (AsymmetricKeyParameter)new RsaPrivateCrtKeyParameters(instance.Modulus,instance.PublicExponent, instance.PrivateExponent, instance.Prime1, instance.Prime2, instance.Exponent1,instance.Exponent2, instance.Coefficient);var keyPair = new AsymmetricCipherKeyPair(publicParameter, privateParameter);var subjectPublicKeyInfo = SubjectPublicKeyInfoFactory.CreateSubjectPublicKeyInfo(keyPair.Public);return Base64.ToBase64String(subjectPublicKeyInfo.GetEncoded());}

/// <summary>/// 从Pkcs8私钥中提取公钥/// </summary>/// <param name="privateKey">Pkcs8私钥</param>/// <returns></returns>public static string GetPublicKeyFromPrivateKeyPkcs8(string privateKey){var privateKeyInfo = PrivateKeyInfo.GetInstance(Asn1Object.FromByteArray(Base64.Decode(privateKey)));privateKey = Base64.ToBase64String(privateKeyInfo.ParsePrivateKey().GetEncoded());var instance = RsaPrivateKeyStructure.GetInstance(Base64.Decode(privateKey));var publicParameter = (AsymmetricKeyParameter)new RsaKeyParameters(false, instance.Modulus,instance.PublicExponent);var privateParameter = (AsymmetricKeyParameter)new RsaPrivateCrtKeyParameters(instance.Modulus,instance.PublicExponent, instance.PrivateExponent, instance.Prime1, instance.Prime2, instance.Exponent1,instance.Exponent2, instance.Coefficient);var keyPair = new AsymmetricCipherKeyPair(publicParameter, privateParameter);var subjectPublicKeyInfo = SubjectPublicKeyInfoFactory.CreateSubjectPublicKeyInfo(keyPair.Public);return Base64.ToBase64String(subjectPublicKeyInfo.GetEncoded());}

PEM操作

PEM格式密钥读取

public static string ReadPkcs1PrivateKey(string text){if (!text.StartsWith("-----BEGIN RSA PRIVATE KEY-----")){return text;}using (var reader = new StringReader(text)){var pr = new PemReader(reader);var keyPair = pr.ReadObject() as AsymmetricCipherKeyPair;pr.Reader.Close();var privateKeyInfo = PrivateKeyInfoFactory.CreatePrivateKeyInfo(keyPair?.Private);return Base64.ToBase64String(privateKeyInfo.ParsePrivateKey().GetEncoded());}}public static string ReadPkcs8PrivateKey(string text){if (!text.StartsWith("-----BEGIN PRIVATE KEY-----")){return text;}using (var reader = new StringReader(text)){var pr = new PemReader(reader);var akp = pr.ReadObject() as AsymmetricKeyParameter; ;pr.Reader.Close();return Base64.ToBase64String(PrivateKeyInfoFactory.CreatePrivateKeyInfo(akp).GetEncoded());}}public static string ReadPublicKey(string text){if (!text.StartsWith("-----BEGIN PUBLIC KEY-----")){return text;}using (var reader = new StringReader(text)){var pr = new PemReader(reader);var keyPair = pr.ReadObject() as AsymmetricCipherKeyPair;pr.Reader.Close();var subjectPublicKeyInfo = SubjectPublicKeyInfoFactory.CreateSubjectPublicKeyInfo(keyPair?.Public);returnBase64.ToBase64String(subjectPublicKeyIno.GetEncoded());}}

PEM格式密钥写入

public static string WritePkcs1PrivateKey(string privateKey){if (privateKey.StartsWith("-----BEGIN RSA PRIVATE KEY-----")){return privateKey;}var akp = RSAUtilities.GetAsymmetricKeyParameterFormPrivateKey(privateKey);using (var sw = new StringWriter()){var pWrt = new PemWriter(sw);pWrt.WriteObject(akp);pWrt.Writer.Close();return sw.ToString();}}public static string WritePkcs8PrivateKey(string privateKey){if (privateKey.StartsWith("-----BEGIN PRIVATE KEY-----")){return privateKey;}var akp = RSAUtilities.GetAsymmetricKeyParameterFormAsn1PrivateKey(privateKey);using (var sw = new StringWriter()){var pWrt = new PemWriter(sw);var pkcs8 = new Pkcs8Generator(akp);pWrt.WriteObject(pkcs8);pWrt.Writer.Close();return sw.ToString();}}public static string WritePublicKey(string publicKey){if (publicKey.StartsWith("-----BEGIN PUBLIC KEY-----")){return publicKey;}var akp = RSAUtilities.GetAsymmetricKeyParameterFormPublicKey(publicKey);using (var sw = new StringWriter()){var pWrt = new PemWriter(sw);pWrt.WriteObject(akp);pWrt.Writer.Close();return sw.ToString();}}

RSA加解密

获取非对称秘钥参数（AsymmetricKeyParameter）

/// <summary>/// -----BEGIN RSA PRIVATE KEY-----/// .../// -----END RSA PRIVATE KEY-----/// </summary>/// <param name="privateKey">Pkcs1格式私钥</param>/// <returns></returns>public static AsymmetricKeyParameter GetAsymmetricKeyParameterFormPrivateKey(string privateKey){if (string.IsNullOrEmpty(privateKey)){throw new ArgumentNullException(nameof(privateKey));}var instance = RsaPrivateKeyStructure.GetInstance(Base64.Decode(privateKey));return new RsaPrivateCrtKeyParameters(instance.Modulus, instance.PublicExponent, instance.PrivateExponent,instance.Prime1, instance.Prime2, instance.Exponent1, instance.Exponent2, instance.Coefficient);}/// <summary>/// -----BEGIN PRIVATE KEY-----/// .../// -----END PRIVATE KEY-----/// </summary>/// <param name="privateKey">Pkcs8格式私钥</param>/// <returns></returns>public static AsymmetricKeyParameter GetAsymmetricKeyParameterFormAsn1PrivateKey(string privateKey){return PrivateKeyFactory.CreateKey(Base64.Decode(privateKey));}/// <summary>/// -----BEGIN PUBLIC KEY-----/// .../// -----END PUBLIC KEY-----/// </summary>/// <param name="publicKey">公钥</param>/// <returns></returns>public static AsymmetricKeyParameter GetAsymmetricKeyParameterFormPublicKey(string publicKey){if (string.IsNullOrEmpty(publicKey)){throw new ArgumentNullException(nameof(publicKey));}return PublicKeyFactory.CreateKey(Base64.Decode(publicKey));}

RSA加解与解密

/// <summary>/// RSA加密/// </summary>/// <param name="data">未加密数据字节数组</param>/// <param name="parameters">非对称密钥参数</param>/// <param name="algorithm">密文算法</param>/// <returns>已加密数据字节数组</returns>public static byte[] Encrypt(byte[] data, AsymmetricKeyParameter parameters, string algorithm){if (data == null){throw new ArgumentNullException(nameof(data));}if (parameters == null){throw new ArgumentNullException(nameof(parameters));}if (string.IsNullOrEmpty(algorithm)){throw new ArgumentNullException(nameof(algorithm));}var bufferedCipher = CipherUtilities.GetCipher(algorithm);bufferedCipher.Init(true, parameters);return bufferedCipher.DoFinal(data);}/// <summary>/// RSA解密/// </summary>/// <param name="data">已加密数据字节数组</param>/// <param name="parameters">非对称密钥参数</param>/// <param name="algorithm">密文算法</param>/// <returns>未加密数据字节数组</returns>public static byte[] Decrypt(byte[] data, AsymmetricKeyParameter parameters, string algorithm){if (data == null){throw new ArgumentNullException(nameof(data));}if (parameters == null){throw new ArgumentNullException(nameof(parameters));}if (string.IsNullOrEmpty(algorithm)){throw new ArgumentNullException(nameof(algorithm));}var bufferedCipher = CipherUtilities.GetCipher(algorithm);bufferedCipher.Init(false, parameters);return bufferedCipher.DoFinal(data);}/// <summary>/// RSA加密——Base64/// </summary>/// <param name="data">未加密字符串</param>/// <param name="parameters">非对称密钥参数</param>/// <param name="algorithm">密文算法</param>/// <returns>已加密Base64字符串</returns>public static string EncryptToBase64(string data, AsymmetricKeyParameter parameters, string algorithm){return Base64.ToBase64String(Encrypt(Encoding.UTF8.GetBytes(data), parameters, algorithm));}/// <summary>/// RSA解密——Base64/// </summary>/// <param name="data">已加密Base64字符串</param>/// <param name="parameters">非对称密钥参数</param>/// <param name="algorithm">密文算法</param>/// <returns>未加密字符串</returns>public static string DecryptFromBase64(string data, AsymmetricKeyParameter parameters, string algorithm){return Encoding.UTF8.GetString(Decrypt(Base64.Decode(data), parameters, algorithm));}/// <summary>/// RSA加密——十六进制/// </summary>/// <param name="data">未加密字符串</param>/// <param name="parameters">非对称密钥参数</param>/// <param name="algorithm">密文算法</param>/// <returns>已加密十六进制字符串</returns>public static string EncryptToHex(string data, AsymmetricKeyParameter parameters, string algorithm){return Hex.ToHexString(Encrypt(Encoding.UTF8.GetBytes(data), parameters, algorithm));}///  <summary>/// RSA解密——十六进制/// </summary>/// <param name="data">已加密十六进制字符串</param>/// <param name="parameters">非对称密钥参数</param>/// <param name="algorithm">密文算法</param>/// <returns>未加密字符串</returns>public static string DecryptFromHex(string data, AsymmetricKeyParameter parameters, string algorithm){return Encoding.UTF8.GetString(Decrypt(Hex.Decode(data), parameters, algorithm));}

RSA密文算法

public const string RSA_NONE_NoPadding = "RSA/NONE/NoPadding";public const string RSA_NONE_PKCS1Padding = "RSA/NONE/PKCS1Padding";public const string RSA_NONE_OAEPPadding = "RSA/NONE/OAEPPadding";public const string RSA_NONE_OAEPWithSHA1AndMGF1Padding = "RSA/NONE/OAEPWithSHA1AndMGF1Padding";public const string RSA_NONE_OAEPWithSHA224AndMGF1Padding = "RSA/NONE/OAEPWithSHA224AndMGF1Padding";public const string RSA_NONE_OAEPWithSHA256AndMGF1Padding = "RSA/NONE/OAEPWithSHA256AndMGF1Padding";public const string RSA_NONE_OAEPWithSHA384AndMGF1Padding = "RSA/NONE/OAEPWithSHA384AndMGF1Padding";public const string RSA_NONE_OAEPWithMD5AndMGF1Padding = "RSA/NONE/OAEPWithMD5AndMGF1Padding";public const string RSA_ECB_NoPadding = "RSA/ECB/NoPadding";public const string RSA_ECB_PKCS1Padding = "RSA/ECB/PKCS1Padding";public const string RSA_ECB_OAEPPadding = "RSA/ECB/OAEPPadding";public const string RSA_ECB_OAEPWithSHA1AndMGF1Padding = "RSA/ECB/OAEPWithSHA1AndMGF1Padding";public const string RSA_ECB_OAEPWithSHA224AndMGF1Padding = "RSA/ECB/OAEPWithSHA224AndMGF1Padding";public const string RSA_ECB_OAEPWithSHA256AndMGF1Padding = "RSA/ECB/OAEPWithSHA256AndMGF1Padding";public const string RSA_ECB_OAEPWithSHA384AndMGF1Padding = "RSA/ECB/OAEPWithSHA384AndMGF1Padding";public const string RSA_ECB_OAEPWithMD5AndMGF1Padding = "RSA/ECB/OAEPWithMD5AndMGF1Padding";......

编码算法

大家要明白，不管是对称算法还是非对称算法，其输入与输出均是字节数组，通常我们要结合编码算法对加密之后或解密之前的数据，进行编码操作。

BouncyCastle提供的Base64编码算法

namespace Org.BouncyCastle.Utilities.Encoders{public sealed class Base64{//public static byte[] Decode(byte[] data);//public static byte[] Decode(string data);//public static int Decode(string data, Stream outStream);//public static byte[] Encode(byte[] data);//public static byte[] Encode(byte[] data, int off, int length);//public static int Encode(byte[] data, Stream outStream);//public static int Encode(byte[] data, int off, int length, Stream outStream);public static string ToBase64String(byte[] data);public static string ToBase64String(byte[] data, int off, int length);}}

BouncyCastle提供的Hex十六进制编码算法

namespace Org.BouncyCastle.Utilities.Encoders{//// 摘要://     Class to decode and encode Hex.public sealed class Hex{//public static byte[] Decode(byte[] data);//public static byte[] Decode(string data);//public static int Decode(string data, Stream outStream);//public static byte[] Encode(byte[] data);//public static byte[] Encode(byte[] data, int off, int length);//public static int Encode(byte[] data, Stream outStream);//public static int Encode(byte[] data, int off, int length, Stream outStream);public static string ToHexString(byte[] data);public static string ToHexString(byte[] data, int off, int length);}}

RSA加解密示例

private static void RSA_ECB_PKCS1Padding(){var data = "hello rsa";Console.WriteLine($"加密原文：{data}");// rsa pkcs8 private key encrypt//algorithm  rsa/ecb/pkcs1paddingvar pkcs8data = RSA.EncryptToBase64(data, RSAUtilities.GetAsymmetricKeyParameterFormAsn1PrivateKey(pkcs8_1024_private_key),CipherAlgorithms.RSA_ECB_PKCS1Padding);Console.WriteLine("密钥格式：pkcs8，密文算法：rsa/ecb/pkcs1padding，加密结果");Console.WriteLine(pkcs8data);//rsa pkcs1 private key encrypt//algorithm  rsa/ecb/pkcs1paddingvar pkcs1data = RSA.EncryptToBase64(data, RSAUtilities.GetAsymmetricKeyParameterFormPrivateKey(pkcs1_1024_private_key),CipherAlgorithms.RSA_ECB_PKCS1Padding);Console.WriteLine($"密钥格式：pkcs1，密文算法：rsa/ecb/pkcs1padding");Console.WriteLine(pkcs1data);Console.WriteLine($"加密结果比对是否一致：{pkcs8data.Equals(pkcs1data)}");var _1024_public_key = RSAKeyConverter.GetPublicKeyFromPrivateKeyPkcs1(pkcs1_1024_private_key);Console.WriteLine($"从pkcs1私钥中提取公钥：");Console.WriteLine(_1024_public_key);Console.WriteLine("使用公钥解密数据：");//rsa public key decrypt//algorithm  rsa/ecb/pkcs1paddingConsole.WriteLine(RSA.DecryptFromBase64(pkcs1data, RSAUtilities.GetAsymmetricKeyParameterFormPublicKey(_1024_public_key),CipherAlgorithms.RSA_ECB_PKCS1Padding));Console.WriteLine();}

下期预告

下一篇将介绍哈希算法（HMACSHA1、HMACSHA256、SHA1、SHA1WithRSA、SHA256、SHA256WithRSA），敬请期待…