rsa是非對稱加密，有公鑰和私鑰
公鑰用於加密，私鑰用於解密，私鑰無法加密，但是私鑰可以對內容簽名，公鑰可以對簽名進行驗證，這是rsa常用的使用場景
如果你想加密一小段關鍵的信息，那麼你可以用公鑰進行加密，對方收到後用私鑰進行解密。
如果你想發送一段文字，內容很長，你並不需要對內容進行加密，只是想用私鑰對內容進行數字簽名，對方收到你發的信息後，可以通過公鑰驗證簽名來證實這段信息是不是你發的，並且發的消息有沒有被篡改過。
所以這是rsa基本的兩種使用場景。
public class RSACryption { #region RSA 加密解密 #region RSA 的密鑰產生 /// <summary> /// RSA產生密鑰 /// </summary> /// <param name="xmlKeys">私鑰</param> /// <param name="xmlPublicKey">公鑰</param> public void RSAKey(out string xmlKeys, out string xmlPublicKey) { try { System.Security.Cryptography.RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(); xmlKeys = rsa.ToXmlString(true); xmlPublicKey = rsa.ToXmlString(false); } catch (Exception ex) { throw ex; } } /// <summary> /// 生成密鑰文件 /// </summary> public void RSACreateKeyFile() { try { RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(); using (StreamWriter writer = new StreamWriter("PrivateKey.key")) //這個文件要保密... { writer.WriteLine(rsa.ToXmlString(true)); } using (StreamWriter writer = new StreamWriter("PublicKey.key")) { writer.WriteLine(rsa.ToXmlString(false)); } } catch (Exception ex) { throw ex; } } /// <summary> /// 讀取可執行目錄下的key文件內容 /// </summary> /// <param name="directory"></param> /// <returns></returns> public string ReadKeyFile(string directory) { try { string key = string.Empty; //查找目錄下的.KEY後綴文件 獲取密鑰 DirectoryInfo directoryInfo = new DirectoryInfo(directory); var keyFiles = directoryInfo.GetFiles("*.KEY", SearchOption.TopDirectoryOnly).OrderByDescending(m => m.CreationTime).ToList(); if (keyFiles.Any()) { var keyFile = keyFiles[0]; key = ReadFile(keyFile.FullName); return key; } else { return string.Empty; } } catch (Exception ex) { throw ex; } } /// <summary> /// 獲取可執行目錄下的key文件內容 /// </summary> /// <param name="directory"></param> /// <param name="keyFileName"></param> /// <returns></returns> public string ReadKeyFile(string directory, string keyFileName) { try { string key = string.Empty; //查找目錄下的.KEY後綴文件 獲取密鑰 DirectoryInfo directoryInfo = new DirectoryInfo(directory); var keyFiles = directoryInfo.GetFiles(keyFileName, SearchOption.TopDirectoryOnly).OrderByDescending(m => m.CreationTime).ToList(); if (keyFiles.Any()) { var keyFile = keyFiles[0]; key = ReadFile(keyFile.FullName); return key; } else { return string.Empty; } } catch (Exception ex) { throw ex; } } private string ReadFile(string path) { StringBuilder sb = new StringBuilder(); try { using (StreamReader sr = new StreamReader(path)) { string line; // 從文件讀取並顯示行，直到文件的末尾 while ((line = sr.ReadLine()) != null) { sb.Append(line); } } return sb.ToString(); } catch (Exception e) { throw e; } } #endregion #region RSA加密函數 /// <summary> /// RSA的加密函數 /// </summary> /// <param name="xmlPublicKey">公鑰</param> /// <param name="encryptString">待加密的字符串</param> /// <returns></returns> public string RSAEncrypt(string xmlPublicKey, string encryptString) { try { byte[] PlainTextBArray; byte[] CypherTextBArray; string Result; System.Security.Cryptography.RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(); rsa.FromXmlString(xmlPublicKey); PlainTextBArray = Encoding.UTF8.GetBytes(encryptString); CypherTextBArray = rsa.Encrypt(PlainTextBArray, false); Result = Convert.ToBase64String(CypherTextBArray); return Result; } catch (Exception ex) { throw ex; } } /// <summary> /// RSA的加密函數 /// </summary> /// <param name="xmlPublicKey">公鑰</param> /// <param name="EncryptString">待加密的字節數組</param> /// <returns></returns> public string RSAEncrypt(string xmlPublicKey, byte[] EncryptString) { try { byte[] CypherTextBArray; string Result; System.Security.Cryptography.RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(); rsa.FromXmlString(xmlPublicKey); CypherTextBArray = rsa.Encrypt(EncryptString, false); Result = Convert.ToBase64String(CypherTextBArray); return Result; } catch (Exception ex) { throw ex; } } #endregion #region RSA的解密函數 /// <summary> /// RSA的解密函數 /// </summary> /// <param name="xmlPrivateKey">私鑰</param> /// <param name="decryptString">待解密的字符串</param> /// <returns></returns> public string RSADecrypt(string xmlPrivateKey, string decryptString) { try { byte[] PlainTextBArray; byte[] DypherTextBArray; string Result; System.Security.Cryptography.RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(); rsa.FromXmlString(xmlPrivateKey); PlainTextBArray = Convert.FromBase64String(decryptString); DypherTextBArray = rsa.Decrypt(PlainTextBArray, false); Result = Encoding.UTF8.GetString(DypherTextBArray); return Result; } catch (Exception ex) { throw ex; } } /// <summary> /// RSA的解密函數 /// </summary> /// <param name="xmlPrivateKey">私鑰</param> /// <param name="DecryptString">待解密的字節數組</param> /// <returns></returns> public string RSADecrypt(string xmlPrivateKey, byte[] DecryptString) { try { byte[] DypherTextBArray; string Result; System.Security.Cryptography.RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(); rsa.FromXmlString(xmlPrivateKey); DypherTextBArray = rsa.Decrypt(DecryptString, false); Result = Encoding.UTF8.GetString(DypherTextBArray); return Result; } catch (Exception ex) { throw ex; } } #endregion #endregion #region RSA數字簽名 #region 獲取Hash描述表 /// <summary> /// 獲取Hash描述表 /// </summary> /// <param name="strSource">待簽名的字符串</param> /// <param name="HashData">Hash描述</param> /// <returns></returns> public byte[] GetHashByte(string strSource) { try { byte[] Buffer; System.Security.Cryptography.HashAlgorithm MD5 = System.Security.Cryptography.HashAlgorithm.Create("MD5"); Buffer = System.Text.Encoding.UTF8.GetBytes(strSource); return MD5.ComputeHash(Buffer); } catch (Exception ex) { throw ex; } } /// <summary> /// 獲取Hash描述表 /// </summary> /// <param name="strSource"></param> /// <returns></returns> public string GetHashStr(string strSource) { try { //從字符串中取得Hash描述 byte[] Buffer; byte[] HashData; System.Security.Cryptography.HashAlgorithm MD5 = System.Security.Cryptography.HashAlgorithm.Create("MD5"); Buffer = System.Text.Encoding.UTF8.GetBytes(strSource); HashData = MD5.ComputeHash(Buffer); return Convert.ToBase64String(HashData); } catch (Exception ex) { throw ex; } } /// <summary> /// 獲取Hash描述表 /// </summary> /// <param name="objFile"></param> /// <returns></returns> public byte[] GetHashByte(System.IO.FileStream objFile) { try { //從文件中取得Hash描述 System.Security.Cryptography.HashAlgorithm MD5 = System.Security.Cryptography.HashAlgorithm.Create("MD5"); byte[] HashData = MD5.ComputeHash(objFile); objFile.Close(); return HashData; } catch (Exception ex) { throw ex; } } /// <summary> /// 獲取Hash描述表 /// </summary> /// <param name="objFile"></param> /// <returns></returns> public string GetHashStr(System.IO.FileStream objFile) { try { //從文件中取得Hash描述 byte[] HashData; System.Security.Cryptography.HashAlgorithm MD5 = System.Security.Cryptography.HashAlgorithm.Create("MD5"); HashData = MD5.ComputeHash(objFile); objFile.Close(); return Convert.ToBase64String(HashData); } catch (Exception ex) { throw ex; } } #endregion #region RSA簽名 /// <summary> /// RSA簽名 /// </summary> /// <param name="strKeyPrivate"></param> /// <param name="HashbyteSignature"></param> /// <returns></returns> public string Signature(string strKeyPrivate, byte[] HashbyteSignature) { try { byte[] EncryptedSignatureData; System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); RSA.FromXmlString(strKeyPrivate); System.Security.Cryptography.RSAPKCS1SignatureFormatter RSAFormatter = new System.Security.Cryptography.RSAPKCS1SignatureFormatter(RSA); //設置簽名的算法爲MD5 RSAFormatter.SetHashAlgorithm("MD5"); //執行簽名 EncryptedSignatureData = RSAFormatter.CreateSignature(HashbyteSignature); return Convert.ToBase64String(EncryptedSignatureData); } catch (Exception ex) { throw ex; } } /// <summary> /// RSA簽名 /// </summary> /// <param name="strKeyPrivate"></param> /// <param name="strHashbyteSignature"></param> /// <returns></returns> public string Signature(string strKeyPrivate, string strHashbyteSignature) { try { byte[] HashbyteSignature; byte[] EncryptedSignatureData; HashbyteSignature = Convert.FromBase64String(strHashbyteSignature); System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); RSA.FromXmlString(strKeyPrivate); System.Security.Cryptography.RSAPKCS1SignatureFormatter RSAFormatter = new System.Security.Cryptography.RSAPKCS1SignatureFormatter(RSA); //設置簽名的算法爲MD5 RSAFormatter.SetHashAlgorithm("MD5"); //執行簽名 EncryptedSignatureData = RSAFormatter.CreateSignature(HashbyteSignature); return Convert.ToBase64String(EncryptedSignatureData); } catch (Exception ex) { throw ex; } } #endregion #region RSA 簽名驗證 /// <summary> /// RSA簽名驗證 /// </summary> /// <param name="strKeyPublic">公鑰</param> /// <param name="HashbyteDeformatter">Hash描述</param> /// <param name="DeformatterData">簽名後的結果</param> /// <returns></returns> public bool SignatureVerify(string strKeyPublic, byte[] HashbyteDeformatter, byte[] DeformatterData) { try { System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); RSA.FromXmlString(strKeyPublic); System.Security.Cryptography.RSAPKCS1SignatureDeformatter RSADeformatter = new System.Security.Cryptography.RSAPKCS1SignatureDeformatter(RSA); //指定解密的時候HASH算法爲MD5 RSADeformatter.SetHashAlgorithm("MD5"); if (RSADeformatter.VerifySignature(HashbyteDeformatter, DeformatterData)) { return true; } else { return false; } } catch (Exception ex) { throw ex; } } /// <summary> /// RSA簽名驗證 /// </summary> /// <param name="strKeyPublic">公鑰</param> /// <param name="strHashbyteDeformatter">Hash描述</param> /// <param name="DeformatterData">簽名後的結果</param> /// <returns></returns> public bool SignatureVerify(string strKeyPublic, string strHashbyteDeformatter, byte[] DeformatterData) { try { byte[] HashbyteDeformatter; HashbyteDeformatter = Convert.FromBase64String(strHashbyteDeformatter); System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); RSA.FromXmlString(strKeyPublic); System.Security.Cryptography.RSAPKCS1SignatureDeformatter RSADeformatter = new System.Security.Cryptography.RSAPKCS1SignatureDeformatter(RSA); //指定解密的時候HASH算法爲MD5 RSADeformatter.SetHashAlgorithm("MD5"); if (RSADeformatter.VerifySignature(HashbyteDeformatter, DeformatterData)) { return true; } else { return false; } } catch (Exception ex) { throw ex; } } /// <summary> /// RSA簽名驗證 /// </summary> /// <param name="strKeyPublic">公鑰</param> /// <param name="HashbyteDeformatter">Hash描述</param> /// <param name="strDeformatterData">簽名後的結果</param> /// <returns></returns> public bool SignatureVerify(string strKeyPublic, byte[] HashbyteDeformatter, string strDeformatterData) { try { byte[] DeformatterData; System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); RSA.FromXmlString(strKeyPublic); System.Security.Cryptography.RSAPKCS1SignatureDeformatter RSADeformatter = new System.Security.Cryptography.RSAPKCS1SignatureDeformatter(RSA); //指定解密的時候HASH算法爲MD5 RSADeformatter.SetHashAlgorithm("MD5"); DeformatterData = Convert.FromBase64String(strDeformatterData); if (RSADeformatter.VerifySignature(HashbyteDeformatter, DeformatterData)) { return true; } else { return false; } } catch (Exception ex) { throw ex; } } /// <summary> /// RSA簽名驗證 /// </summary> /// <param name="strKeyPublic">公鑰</param> /// <param name="strHashbyteDeformatter">Hash描述</param> /// <param name="strDeformatterData">簽名後的結果</param> /// <returns></returns> public bool SignatureVerify(string strKeyPublic, string strHashbyteDeformatter, string strDeformatterData) { try { byte[] DeformatterData; byte[] HashbyteDeformatter; HashbyteDeformatter = Convert.FromBase64String(strHashbyteDeformatter); System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); RSA.FromXmlString(strKeyPublic); System.Security.Cryptography.RSAPKCS1SignatureDeformatter RSADeformatter = new System.Security.Cryptography.RSAPKCS1SignatureDeformatter(RSA); //指定解密的時候HASH算法爲MD5 RSADeformatter.SetHashAlgorithm("MD5"); DeformatterData = Convert.FromBase64String(strDeformatterData); if (RSADeformatter.VerifySignature(HashbyteDeformatter, DeformatterData)) { return true; } else { return false; } } catch (Exception ex) { throw ex; } } #endregion #endregion }