1 private static readonly Encoding Encoder = Encoding.UTF8; 2 3 public static String Encrypt(this String plaintext) 4 { 5 X509Certificate2 _X509Certificate2 = RSAHelper.RetrieveX509Certificate(); 6 string publickey = @"<RSAKeyValue><Modulus>5m9m14XH3oqLJ8bNGw9e4rGpXpcktv9MSkHSVFVMjHbfv+SJ5v0ubqQxa5YjLN4vc49z7SVju8s0X4gZ6AzZTn06jzWOgyPRV54Q4I0DCYadWW4Ze3e+BOtwgVU1Og3qHKn8vygoj40J6U85Z/PTJu3hN1m75Zr195ju7g9v4Hk=</Modulus><Exponent>AQAB</Exponent></RSAKeyValue>"; 7 using (RSACryptoServiceProvider RSACryptography = /*_X509Certificate2.PublicKey.Key as*/ new RSACryptoServiceProvider()) 8 { 9 RSACryptography.FromXmlString(publickey); 10 Byte[] PlaintextData = RSAHelper.Encoder.GetBytes(plaintext); 11 int MaxBlockSize = RSACryptography.KeySize / 8 - 11; //加密塊最大長度限制 12 13 if (PlaintextData.Length <= MaxBlockSize) 14 return Convert.ToBase64String(RSACryptography.Encrypt(PlaintextData, false)); 15 16 using (MemoryStream PlaiStream = new MemoryStream(PlaintextData)) 17 using (MemoryStream CrypStream = new MemoryStream()) 18 { 19 Byte[] Buffer = new Byte[MaxBlockSize]; 20 int BlockSize = PlaiStream.Read(Buffer, 0, MaxBlockSize); 21 22 while (BlockSize > 0) 23 { 24 Byte[] ToEncrypt = new Byte[BlockSize]; 25 Array.Copy(Buffer, 0, ToEncrypt, 0, BlockSize); 26 27 Byte[] Cryptograph = RSACryptography.Encrypt(ToEncrypt, false); 28 CrypStream.Write(Cryptograph, 0, Cryptograph.Length); 29 30 BlockSize = PlaiStream.Read(Buffer, 0, MaxBlockSize); 31 } 32 33 return Convert.ToBase64String(CrypStream.ToArray(), Base64FormattingOptions.None); 34 } 35 } 36 } 37 38 public static String Decrypt(this String ciphertext) 39 { 40 X509Certificate2 _X509Certificate2 = RSAHelper.RetrieveX509Certificate(); 41 string privatekey = @"<RSAKeyValue><Modulus>5m9m14XH3oqLJ8bNGw9e4rGpXpcktv9MSkHSVFVMjHbfv+SJ5v0ubqQxa5YjLN4vc49z7SVju8s0X4gZ6AzZTn06jzWOgyPRV54Q4I0DCYadWW4Ze3e+BOtwgVU1Og3qHKn8vygoj40J6U85Z/PTJu3hN1m75Zr195ju7g9v4Hk=</Modulus><Exponent>AQAB</Exponent><P>/hf2dnK7rNfl3lbqghWcpFdu778hUpIEBixCDL5WiBtpkZdpSw90aERmHJYaW2RGvGRi6zSftLh00KHsPcNUMw==</P><Q>6Cn/jOLrPapDTEp1Fkq+uz++1Do0eeX7HYqi9rY29CqShzCeI7LEYOoSwYuAJ3xA/DuCdQENPSoJ9KFbO4Wsow==</Q><DP>ga1rHIJro8e/yhxjrKYo/nqc5ICQGhrpMNlPkD9n3CjZVPOISkWF7FzUHEzDANeJfkZhcZa21z24aG3rKo5Qnw==</DP><DQ>MNGsCB8rYlMsRZ2ek2pyQwO7h/sZT8y5ilO9wu08Dwnot/7UMiOEQfDWstY3w5XQQHnvC9WFyCfP4h4QBissyw==</DQ><InverseQ>EG02S7SADhH1EVT9DD0Z62Y0uY7gIYvxX/uq+IzKSCwB8M2G7Qv9xgZQaQlLpCaeKbux3Y59hHM+KpamGL19Kg==</InverseQ><D>vmaYHEbPAgOJvaEXQl+t8DQKFT1fudEysTy31LTyXjGu6XiltXXHUuZaa2IPyHgBz0Nd7znwsW/S44iql0Fen1kzKioEL3svANui63O3o5xdDeExVM6zOf1wUUh/oldovPweChyoAdMtUzgvCbJk1sYDJf++Nr0FeNW1RB1XG30=</D></RSAKeyValue>"; 42 using (RSACryptoServiceProvider RSACryptography = /*_X509Certificate2.PrivateKey as*/ new RSACryptoServiceProvider()) 43 { 44 RSACryptography.FromXmlString(privatekey); 45 Byte[] CiphertextData = Convert.FromBase64String(ciphertext); 46 int MaxBlockSize = RSACryptography.KeySize / 8; //解密塊最大長度限制 47 48 if (CiphertextData.Length <= MaxBlockSize) 49 return RSAHelper.Encoder.GetString(RSACryptography.Decrypt(CiphertextData, false)); 50 51 using (MemoryStream CrypStream = new MemoryStream(CiphertextData)) 52 using (MemoryStream PlaiStream = new MemoryStream()) 53 { 54 Byte[] Buffer = new Byte[MaxBlockSize]; 55 int BlockSize = CrypStream.Read(Buffer, 0, MaxBlockSize); 56 57 while (BlockSize > 0) 58 { 59 Byte[] ToDecrypt = new Byte[BlockSize]; 60 Array.Copy(Buffer, 0, ToDecrypt, 0, BlockSize); 61 62 Byte[] Plaintext = RSACryptography.Decrypt(ToDecrypt, false); 63 PlaiStream.Write(Plaintext, 0, Plaintext.Length); 64 65 BlockSize = CrypStream.Read(Buffer, 0, MaxBlockSize); 66 } 67 68 return RSAHelper.Encoder.GetString(PlaiStream.ToArray()); 69 } 70 } 71 } 72 73 private static X509Certificate2 RetrieveX509Certificate() 74 { 75 76 return null; //檢索用於 RSA 加密的 X509Certificate2 證書 77 }