求asp.net C#使用rsa加密的简单完整例子

有一个加密算法，采用密钥加密的。
using System.Security.Cryptography;
//加密
public static String JiaMi(String str)
{
String encryptKey = "Oyea";
DESCryptoServiceProvider descsp = new DESCryptoServiceProvider();
byte[] key = Encoding.Unicode.GetBytes(encryptKey);
byte[] data = Encoding.Unicode.GetBytes(str);
System.IO.MemoryStream MStream = new System.IO.MemoryStream();
CryptoStream CStream = new CryptoStream(MStream, descsp.CreateEncryptor(key, key), CryptoStreamMode.Write);
CStream.Write(data, 0, data.Length);
CStream.FlushFinalBlock();
return Convert.ToBase64String(MStream.ToArray());
}
//解密
public static String JieMi(String str)
{
String encryptKey = "Oyea";
DESCryptoServiceProvider descsp = new DESCryptoServiceProvider();
byte[] key = Encoding.Unicode.GetBytes(encryptKey);
byte[] data = Convert.FromBase64String(str);
System.IO.MemoryStream MStream