. NET encryption and decryption--encryption mode of asymmetric encryption

One, asymmetric encryption

Asymmetric encryption has a set of key pairs, one is public, anyone can obtain, called the public key;

One is self-preservation and strictly confidential, called the private key.

The rules are as follows:

by someone A the public key encrypted message, only by the A the private key is decrypted;

by A The private key encrypts the message, only by the A decryption of the public key.

sender, the receiver holds the public key / private key pair, so there will be a total of four keys. The advantage of non-heap encryption is that the private key is held by itself and the public key is fully exposed.

two, encryption mode

Steps:

1 , the receiver publishes its own public key, which can be obtained by anyone.

2 , the sending party uses Receiving Party the public key of the message is encrypted and then sent.

3 , Receiving Party Use own the private key to decrypt the message.

Disadvantages:

1 , it is not possible to determine who sent the message.

three, encryption mode demo

/*//Encryption Mode */namespace Asymmetric Encryption {class Program {static void Main (string[] args) {string pla            InText = "Hello World"; String PublicKey = "<rsakeyvalue><modulus>qa89wuhlcmvyhjqw+ Mfjrz6ep8xuicvrkvwkuufrhbamlgxt2lhthssbszhfeechqvwgff+oybgj1ki72a3h056tm6yrnppjfajggrnsjswppna14e6f+zbvc/ mzrislgntdxhbhuvnsmx+hlu+skz+b75rcmoyueoup8gxfeqs=</modulus><exponent>aqab</exponent></            Rsakeyvalue> ";  String encryptedtext = Rsacryptohelper.encrypt (PublicKey, plaintext);            Confidential ~ ~ Console.WriteLine (encryptedtext); String Privatekey = "<rsakeyvalue><modulus>qa89wuhlcmvyhjqw+ Mfjrz6ep8xuicvrkvwkuufrhbamlgxt2lhthssbszhfeechqvwgff+oybgj1ki72a3h056tm6yrnppjfajggrnsjswppna14e6f+zbvc/ Mzrislgntdxhbhuvnsmx+hlu+skz+b75rcmoyueoup8gxfeqs=</modulus><exponent>aqab</exponent><p >7vxysshaimztnvzgk3h3u9llnzsa5mck4/ilvatq5h3+yhegt0t+q2tv844quxcbpvkkrf+uvsb043nw65kotw==</p><q>tug739ddgwvrsbxle1zmuabvbzeunuicosbcgp/lsmbscdnk46rifjvz3nglfptbav4i7mpatr8je1o5gl485q==</q><dp> Zyfxnjuyhxuilxzcjcccwb88pvklflceqb0nia1kaqihwjxreakkt/f0vfnk3mvbclyx/bk6ua7egktfrcub+w==</dp><dq> rlubbingbo6/hfjbz6gcpcec4ebyb7s02dygjxzfsyejdhq3a7taw+qn4keshk6cmirrbu7qpjmdvzk3r1wr/q==</dq>< inverseq>a0q3ffhjshdazw0qrkqznunsq+j5/ltps9zajqivho2abayagwkavvsbud7cb+i4easaw4uqhrk456vkw/hqnw==</ inverseq><d>dyxifvafc2jrctd8mkw6e2ttsf6iha1t5y6t+xc5jvd7t/ Yi0qg7ce23bt1tpchc0hgdlstqjs3hgxzx6yjez0frz37uunnsnyrhh3canxquawaczmf7tpyoqbmgxp5ofpgaijumhmwysmm9wdrtoce6h39t5qlly7g6xh9            Mj+k=</d></rsakeyvalue> ";  String cleartext = Rsacryptohelper.decrypt (Privatekey, encryptedtext);            Decryption Console.WriteLine (cleartext);        Console.readkey (); }} public class Rsacryptohelper {#region Key acquisition method-not encapsulated in//method one://string privat ekey= provider. Toxmlstring (TRUE);//Get public/private key pair//String publickey= provider. Toxmlstring (false);//Get public key pair//Method two://rsaparameters Privatekey = provider. Exportparameters (TRUE);//Get the public key to//rsaparameters PublicKey = provider.        Exportparameters (false);//Get public key #endregion///<summary>//Sender encryption///</summary> <param name= "Publickeyxml" >the public key xml.</param>//<param name= "plaintext" >the Plain text.</param>//<returns>System.String.</returns>//<remarks>editor:v-liuh CH createtime:2015/5/16 22:06:54</remarks> public static string Encrypt (string publickeyxml, string plaintext            ) {RSACryptoServiceProvider Provider = new RSACryptoServiceProvider (); Provider. Fromxmlstring (Publickeyxml);            Initialize object with public key byte[] Plaindata = Encoding.Default.GetBytes (plaintext); byte[] EncryptedData = provider. Encrypt (Plaindata, true);//Encrypt data REturn convert.tobase64string (EncryptedData);  }///<summary>////</summary>//<param name= "Privatekeyxml" >the Private key xml.</param>//<param name= "Encryptedtext" >the encrypted text.</param>// <returns>System.String.</returns>//<remarks>editor:v-liuhch createtime:2015/5/16 22:11:09< /remarks> public static string Decrypt (String privatekeyxml, String encryptedtext) {Rsacryptoservice            Provider Provider = new RSACryptoServiceProvider (); Provider.            Fromxmlstring (privatekeyxml);//Use the private key to initialize the data byte[] EncryptedData = convert.frombase64string (encryptedtext); byte[] Plaindata = provider.  Decrypt (EncryptedData, true);  Decrypt the data string plaintext = Encoding.Default.GetString (plaindata);                Clear text return plaintext; }    }}

. NET encryption and decryption--encryption mode of asymmetric encryption