原文:RSACryptoServiceProvider加密解密签名验签和DESCryptoServiceProvider加解密
C#在using System.Security.Cryptography下有 DESCryptoServiceProvider RSACryptoServiceProvider
DESCryptoServiceProvider 是用于对称加密 RSACryptoServiceProvider是用于非对称加密
对称加密的意思：有一个密钥 相当于加密算法，加密用它来加密，解密也需要用到它。因为加密解密都是用同一个密钥所以叫对称加密。 对称加密有一个坏处只要拥有密钥的人都可以解密。
非对称加密：就是有2个密钥，一个是公钥，一个是私钥，私钥是自己的，不能随便给人，公钥随便给，无所谓。一般是别人用你的公钥加密，然后把密文给你，你用你的私钥解密，这样一样加密和解密不是同一个密钥，所以叫非对称。 非对称的好处是假如没有私钥别人是无法解密的，就算加密的那个人他把数据加密了他也无法解密，加密者把密文和公钥随便给那个人都无法解密。
数字签名：数字签名的意义就是这些数据与原文数据比对是否修改过，这个解释有点麻烦，当初我也搞了好久才理解！一般是用自己的私钥对数据进行签名，然后用公钥去验证这个数据是否修改过
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现在该说说DESCryptoServiceProvider 和RSACryptoServiceProvider 在C#中的具体怎么用:
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1、用RSACryptoServiceProvider 加密解密
//加密解密用到的公钥与私钥 RSACryptoServiceProvider oRSA = new RSACryptoServiceProvider(); string privatekey=oRSA.ToXmlString(true);//私钥 string publickey=oRSA.ToXmlString(false);//公钥 //这两个密钥需要保存下来 byte[] messagebytes = Encoding.UTF8.GetBytes("luo罗"); //需要加密的数据 - //公钥加密 RSACryptoServiceProvider oRSA1 = new RSACryptoServiceProvider(); oRSA1.FromXmlString(publickey); //加密要用到公钥所以导入公钥 byte[] AOutput = oRSA1.Encrypt(messagebytes ,false); //AOutput 加密以后的数据 - //私钥解密 RSACryptoServiceProvider oRSA2 = new RSACryptoServiceProvider(); oRSA2.FromXmlString(privatekey); byte[] AInput = oRSA2.Decrypt(AOutput, false); string reslut=Encoding.ASCII.GetString(AInput)
2、用RSACryptoServiceProvider签名验签
byte[] messagebytes = Encoding.UTF8.GetBytes("luo罗"); RSACryptoServiceProvider oRSA = new RSACryptoServiceProvider(); string privatekey = oRSA.ToXmlString(true); string publickey = oRSA.ToXmlString(false); //私钥签名 RSACryptoServiceProvider oRSA3 = new RSACryptoServiceProvider(); oRSA3.FromXmlString(privatekey); byte[] AOutput = oRSA3.SignData(messagebytes, "SHA1"); //公钥验证 RSACryptoServiceProvider oRSA4 = new RSACryptoServiceProvider(); oRSA4.FromXmlString(publickey); bool bVerify = oRSA4.VerifyData(messagebytes, "SHA1", AOutput);
3、用证书进行签名
// 因为一般证书的私钥是不可以导出的所以所以用第2种方法导入私钥的来进行签名行不通 byte[] messagebytes = Encoding.UTF8.GetBytes("luo罗"); string Path = @"D:\Certificate\1.P12"; X509Certificate2 x509 = new X509Certificate2(Path, "12345678"); SHA1 sha1 = new SHA1CryptoServiceProvider(); byte[] hashbytes = sha1.ComputeHash(messagebytes); //对要签名的数据进行哈希 RSAPKCS1SignatureFormatter signe = new RSAPKCS1SignatureFormatter(); signe.SetKey(x509.PrivateKey); //设置签名用到的私钥 signe.SetHashAlgorithm("SHA1"); //设置签名算法 byte[] reslut = signe.CreateSignature(hashbytes); //验签：与第2方法相同 RSACryptoServiceProvider oRSA4 = new RSACryptoServiceProvider(); oRSA4.FromXmlString(x509.PublicKey.Key.ToXmlString(false)); bool bVerify = oRSA4.VerifyData(messagebytes, "SHA1", reslut);
4、用证书加密解密
string Path = @"D:\Certificate\1.P12"; X509Certificate2 x509 = new X509Certificate2(Path, "12345678"); byte[] data = System.Text.Encoding.UTF8.GetBytes("cheshi罗"); - //证书公钥加密 RSACryptoServiceProvider oRSA1 = new RSACryptoServiceProvider(); oRSA1.FromXmlString(x509.PublicKey.Key.ToXmlString(false)); - byte[] AOutput = oRSA1.Encrypt(data, false); - //证书私钥解密 RSACryptoServiceProvider rsa2 = (RSACryptoServiceProvider)x509.PrivateKey; byte[] plainbytes = rsa2.Decrypt(AOutput, false); string reslut = Encoding.UTF8.GetString(plainbytes);
5用证书对文件加密解密，因为文件可能特别大 所以需要用流和buffer的方式来，鄙视把文件全部读到byte[]里进行加密的人，假如文件5G，那全部读到byte[]里崩溃掉
private void Form1_Load(object sender, EventArgs e) { x509=new X509Certificate2(Path, "12345678"); RSACryptoServiceProvider oRSA1 = new RSACryptoServiceProvider(); Encrypt(); Decrypt(); } private void Decrypt() { string FilePath = "2.txt"; string OutFile = "3.txt"; System.IO.FileStream picfs = new System.IO.FileStream(FilePath, System.IO.FileMode.Open); System.IO.FileStream fs = new System.IO.FileStream(OutFile, System.IO.FileMode.OpenOrCreate); oRSA1 = (RSACryptoServiceProvider)x509.PrivateKey; int blocksize = oRSA1.KeySize/8; - byte[] buffer, buffer1, encryblock; bool Closed = true; while (Closed) { buffer = null; buffer = new byte[blocksize]; int k = picfs.Read(buffer, 0, buffer.Length); if (k > 0) { if (blocksize == k) { encryblock = oRSA1.Decrypt(buffer, false); fs.Write(encryblock, 0, encryblock.Length); } else { buffer1 = new byte[k]; for (int i = 0; i < k; i++) { buffer1[i] = buffer[i]; } encryblock = oRSA1.Decrypt(buffer1, false); fs.Write(encryblock, 0, encryblock.Length); } } else { picfs.Close(); fs.Close(); Closed = false; } } - } private void Encrypt() { string FilePath = "1.txt"; string OutFile = "2.txt"; //证书公钥加密 - oRSA1.FromXmlString(x509.PublicKey.Key.ToXmlString(false)); System.IO.FileStream picfs = new System.IO.FileStream(FilePath, System.IO.FileMode.Open); System.IO.FileStream fs = new System.IO.FileStream(OutFile, System.IO.FileMode.OpenOrCreate); int blocksize = 0; if (oRSA1.KeySize == 1024) { blocksize = 16; } else { blocksize = 8; } byte[] buffer, buffer1, encryblock; bool Closed = true; while (Closed) { buffer = null; buffer = new byte[blocksize]; int k = picfs.Read(buffer, 0, buffer.Length); if (k > 0) { if (blocksize == k) { encryblock = oRSA1.Encrypt(buffer, false); fs.Write(encryblock, 0, encryblock.Length); } else { buffer1 = new byte[k]; for (int i = 0; i < k; i++) { buffer1[i] = buffer[i]; } encryblock = oRSA1.Encrypt(buffer1, false); fs.Write(encryblock, 0, encryblock.Length); } } else { picfs.Close(); fs.Close(); Closed = false; } } }
6用证书对文件进行签名验签，因为文件可能特别大 所以需要用流和buffer的方式来
private void Form1_Load(object sender, EventArgs e) { x509 = new X509Certificate2(Path, "12345678"); SignFile("1.txt", "11.txt"); VerifyFile("1.txt", "11.txt"); } private bool VerifyFile(string FileName, string SignedFileName) { bool reslut = true; System.IO.StreamReader objread = new System.IO.StreamReader(FileName); System.IO.StreamReader objreadSigned = new System.IO.StreamReader(SignedFileName); RSACryptoServiceProvider VeryRsa = new RSACryptoServiceProvider(); VeryRsa.FromXmlString(x509.PublicKey.Key.ToXmlString(false)); int Inblocksize = 0; int Signedblocksize = 0; if (VeryRsa.KeySize == 1024) { Inblocksize = 16; } else { Inblocksize = 8; } Signedblocksize = VeryRsa.KeySize / 8; bool Closed = true; byte[] Buffer; //原文缓存区 byte[] InBuffer;//原文缓存区 byte[] Buffer1;//签名文件缓存区 while (Closed) { Buffer = null; Buffer = new byte[Inblocksize]; int k = objread.BaseStream.Read(Buffer, 0, Buffer.Length); if (k > 0) { if (Inblocksize == k) //读出来的长度和缓存区一样大 { Buffer1 = new byte[Signedblocksize]; objreadSigned.BaseStream.Read(Buffer1, 0, Buffer1.Length); reslut = VeryRsa.VerifyData(Buffer,"SHA1",Buffer1); if (!reslut) { Closed = false; } } else { //意思是Buffer没满，只有k个字节，k字节后面全是空所以不需要验签 InBuffer = new byte[k]; for (int i = 0; i < k; i++) { InBuffer[i] = Buffer[i]; } Buffer1 = new byte[Signedblocksize]; objreadSigned.BaseStream.Read(Buffer1, 0, Buffer1.Length); reslut = VeryRsa.VerifyData(InBuffer, "SHA1", Buffer1); if (!reslut) { Closed = false; } } } else { //这里的意思是原文已经读完毕了，并且已经和签名文件对应验签成功，那么 //签名文件也必须读完毕了。 if (objreadSigned.BaseStream.Position!= objreadSigned.BaseStream.Length) { reslut = false; } objreadSigned.Close(); objread.Close(); Closed = false; } } return reslut; } private void SignFile(string InFileName,string OutFileName) { RSACryptoServiceProvider SignRsa = (RSACryptoServiceProvider)x509.PrivateKey; System.IO.StreamReader objread = new System.IO.StreamReader(InFileName); System.IO.StreamWriter objwrite = new System.IO.StreamWriter(OutFileName, false); int blocksize = 0; if (SignRsa.KeySize == 1024) { blocksize = 16; } else { blocksize = 8; } bool Closed = true; byte[] Buffer = new byte[blocksize]; byte[] buffer1, SignBytes; while (Closed) { int k = objread.BaseStream.Read(Buffer, 0, Buffer.Length); if (k > 0) { if (k == blocksize) { SignBytes = SignRsa.SignData(Buffer, "SHA1"); objwrite.BaseStream.Write(SignBytes, 0, SignBytes.Length); } else { buffer1 = new byte[k]; for (int i = 0; i < k; i++) { buffer1[i] = Buffer[i]; } SignBytes = SignRsa.SignData(buffer1, "SHA1"); objwrite.BaseStream.Write(SignBytes, 0, SignBytes.Length); } } else { Closed = false; objread.Close(); objwrite.Close(); } } }
7、用DESCryptoServiceProvider 进行对称加密
byte[] messagebytes = Encoding.UTF8.GetBytes("LUO罗"); //需要用的对称密钥 DESCryptoServiceProvider Des = new DESCryptoServiceProvider(); byte[] key = Des.Key; //加密 DESCryptoServiceProvider tdesProvider = new DESCryptoServiceProvider(); tdesProvider.Key = key; tdesProvider.Mode = CipherMode.ECB; byte[] encrypted = tdesProvider.CreateEncryptor().TransformFinalBlock(messagebytes, 0, messagebytes.Length); //解密 DESCryptoServiceProvider tdesProvider2 = new DESCryptoServiceProvider(); tdesProvider.Key = key1; tdesProvider.Mode = CipherMode.ECB; byte[] outputdata = tdesProvider.CreateDecryptor().TransformFinalBlock(encrypted, 0, encrypted.Length); string reslut = Encoding.UTF8.GetString(outputdata); //7用DESCryptoServiceProvider 加解密 流 CryptoStream csDecrypt = new CryptoStream(Stream, Des.CreateEncryptor(), CryptoStreamMode.Write); CryptoStream csDecrypt = new CryptoStream(Stream, Des.CreateDecryptor(), CryptoStreamMode.Write);