C#对称加密（3des）和非对称加密（rsa）算法
3DES加密/解密算法的C#实现：（实现的方式很多，仅供参考）
public static bool DecryptFromBase64(string base64String, string key,out string DecryptString)
{
DecryptString = "";
try
{
// encode to bytes
byte[] KEY = HexStringToByteArray(key);
byte[] CRYPTSTRING = Convert.FromBase64String(base64String);
//set iv and key
byte[] tmpiv = { 49, 50, 51, 52, 53, 54, 55, 56 };
byte[] tmpkey = { 0, 1, 2, 3, 4, 5, 6, 7, 0, 1, 2, 3, 4, 5, 6, 7, 0, 1, 2, 3, 4, 5, 6, 7 };
for (int ii = 0; ii < 24; ii++)
{
tmpkey[ii] = KEY[ii];
}
TripleDESCryptoServiceProvider dsp = new TripleDESCryptoServiceProvider();
dsp.Mode = System.Security.Cryptography.CipherMode.CBC;
dsp.Padding = System.Security.Cryptography.PaddingMode.PKCS7;
ICryptoTransform tridesencrypt = dsp.CreateDecryptor(tmpkey, tmpiv);
using (var ms = new MemoryStream(CRYPTSTRING))
{
using (var cs = new CryptoStream(ms, tridesencrypt, CryptoStreamMode.Read))
{
var sr = new StreamReader(cs, Encoding.UTF8);
// 2015/11/11 修改 读取全部内容，而不是只读第一行，此问题乃是算法的bug
DecryptString = sr.ReadToEnd();// sr.ReadLine();
}
}
dsp.Clear();
return true;
}
catch (Exception e)
{
return false;
}
}
public static bool Crypt3DESToBase64(string CryptString, string Key, out string DecryptString)
{
DecryptString = "";
try
{
// encode to bytes
byte[] KEY = HexStringToByteArray(Key);
byte[] CRYPTSTRING = System.Text.Encoding.UTF8.GetBytes(CryptString);
//set iv and key
byte[] tmpiv = { 49, 50, 51, 52, 53, 54, 55, 56 };
byte[] tmpkey = { 0, 1, 2, 3, 4, 5, 6, 7, 0, 1, 2, 3, 4, 5, 6, 7, 0, 1, 2, 3, 4, 5, 6, 7 };
for (int ii = 0; ii < 24; ii++)
{
tmpkey[ii] = KEY[ii];
}
TripleDESCryptoServiceProvider dsp = new TripleDESCryptoServiceProvider();
dsp.Mode = System.Security.Cryptography.CipherMode.CBC;
dsp.Padding = System.Security.Cryptography.PaddingMode.PKCS7;
ICryptoTransform tridesencrypt = dsp.CreateEncryptor(tmpkey, tmpiv);
byte[] results = tridesencrypt.TransformFinalBlock(CRYPTSTRING, 0, CRYPTSTRING.Length);
DecryptString = Convert.ToBase64String(results);
dsp.Clear();
return true;
}
catch (Exception e)
{
return false;
}
}
public static byte[] HexStringToByteArray(string s)
{
Byte[] buf = new byte[s.Length / 2];
for (int i = 0; i < buf.Length; i++)
{
buf[i] = (byte)(chr2hex(s.Substring(i * 2, 1)) * 0x10 + chr2hex(s.Substring(i * 2 + 1, 1)));
}
return buf;
}
private static byte chr2hex(string chr)
{
switch (chr)
{
case "0":
return 0x00;
case "1":
return 0x01;
case "2":
return 0x02;
case "3":
return 0x03;
case "4":
return 0x04;
case "5":
return 0x05;
case "6":
return 0x06;
case "7":
return 0x07;
case "8":
return 0x08;
case "9":
return 0x09;
case "A":
return 0x0a;
case "B":
return 0x0b;
case "C":
return 0x0c;
case "D":
return 0x0d;
case "E":
return 0x0e;
case "F":
return 0x0f;
}
return 0x00;
}
在以上算法中，key为一个48位的字符串，别的就没特别要注意的了。
RSA加密算法（根据MSDN文档实现）：
/// <summary>
/// 使用rsa非对称加密算法加密文本内容
/// </summary>
/// <param name="contentBytes">待加密内容byte数组</param>
/// <param name="publicKey">公开密钥</param>
/// <param name="DoOAEPPadding">建议为false</param>
/// <returns>加密后的byte[]</returns>
public static byte[] RSAEncryptContent(byte[]contentBytes,RSAParameters publicKey,bool DoOAEPPadding)
{
try
{
byte[] encryptedData;
using (RSACryptoServiceProvider provider = new RSACryptoServiceProvider())
{
provider.ImportParameters(publicKey);
encryptedData = provider.Encrypt(contentBytes, DoOAEPPadding);
}
return encryptedData;
}
catch (Exception e)
{
return null;
}
}
/// <summary>
/// 使用rsa非对称加密算法进行解密
/// </summary>
/// <param name="cryptContentBytes">加密后的字节数组</param>
/// <param name="privateKey">私有密钥</param>
/// <param name="DoOAEPPadding">建议为false</param>
/// <returns>解密后的内容数组</returns>
public static byte[] RSADescryptContent(byte[]cryptContentBytes,RSAParameters privateKey,bool DoOAEPPadding)
{
try
{
byte[] decryptData;
using (RSACryptoServiceProvider provider = new RSACryptoServiceProvider())
{
provider.ImportParameters(privateKey);
decryptData = provider.Decrypt(cryptContentBytes, DoOAEPPadding);
}
return decryptData;
}
catch (Exception e)
{
Console.WriteLine(e.Message);
return null;
}
}
使用RSA加密/解密算法的方法：
//content为要进行加密的字符串
byte[] contentBytes = byteConverter.GetBytes(content); byte[] encryptBytes; byte[] decryptBytes; //待加密的字节数不能超过密钥的长度值除以 8 再减去 11（即：RSACryptoServiceProvider.KeySize / 8 - 11） int maxBlockSize; using(RSACryptoServiceProvider provider=new RSACryptoServiceProvider()) { maxBlockSize = provider.KeySize / 8 - 11; RSAParameters publicKey = provider.ExportParameters(false); // 小于最大块值，直接加密 if (contentBytes.Length <= maxBlockSize) { encryptBytes = EncryptContent(contentBytes, publicKey, false); } else { // 分块儿加密 using(MemoryStream plaintStream=new MemoryStream(contentBytes)) using(MemoryStream cryptStream=new MemoryStream()) { byte[] buffer = new byte[maxBlockSize]; int blockSize = plaintStream.Read(buffer, 0, maxBlockSize); while(blockSize>0) { byte[] encryptBlock = new byte[blockSize]; Array.Copy(buffer, encryptBlock, blockSize); byte[]encryptedBlock=EncryptContent(encryptBlock,publicKey,false); cryptStream.Write(encryptedBlock, 0, encryptedBlock.Length); blockSize = plaintStream.Read(buffer, 0, maxBlockSize); } encryptBytes = cryptStream.ToArray(); } } //加密后的字符串 string encryptString = byteConverter.GetString(encryptBytes); Console.WriteLine("加密结束"); Console.ReadLine(); Console.ReadLine();
// 以下为解密过程，解密过程也会有长度限制，可参考加密的方式进行解密 //string encryptString = byteConverter.GetString(encryptBytes); //RSAParameters privateKey = provider.ExportParameters(true); //decryptBytes = DecryptContent(encryptBytes, privateKey, false); //string decryptString = byteConverter.GetString(decryptBytes); //Console.WriteLine(decryptString); }
