c# RSA加密解密分段加密和分段解密

admin · 发表于 2016-4-13 19:13:17

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
namespace YeMao.Common.Security
{
public static class RSACryptoProvider
{
/// <summary>
/// RSA解密
/// </summary>
/// <param name="base64code">需要进行解密的密文字符串</param>
/// <param name="privateKey">私钥</param>
/// <returns>解密后的明文</returns>
public static string Decrypt(string base64code, string privateKey)
{
#region 自己加的
base64code = base64code.Replace(" ", "+");
int mod4 = base64code.Length % 4;
if (mod4 > 0)
{
base64code += new string('=', 4 - mod4);
}
#endregion
UnicodeEncoding ByteConverter = new UnicodeEncoding();
RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();
RSA.FromXmlString(privateKey);
byte[] encryptedData;
byte[] decryptedData;
encryptedData = Convert.FromBase64String(base64code);
decryptedData = RSADecrypt(encryptedData, RSA.ExportParameters(true), false);
return ByteConverter.GetString(decryptedData);
}
/// <summary>
/// RSA分段解密;用于对超长字符串解密
/// </summary>
/// <param name="toEncryptString">需要进行解密的字符串</param>
/// <param name="publickKey">私钥</param>
/// <returns>解密后的明文</returns>
public static string SectionDecrypt(string base64code, string privateKey)
{
#region 自己加的
base64code = base64code.Replace(" ", "+");
int mod4 = base64code.Length % 4;
if (mod4 > 0)
{
base64code += new string('=', 4 - mod4);
}
#endregion
UnicodeEncoding ByteConverter = new UnicodeEncoding();
RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();
RSA.FromXmlString(privateKey);
Byte[] CiphertextData = Convert.FromBase64String(base64code);
int MaxBlockSize = RSA.KeySize / 8;
if (CiphertextData.Length <= MaxBlockSize)
{
byte[] decryptedData;
decryptedData = RSADecrypt(CiphertextData, RSA.ExportParameters(true), false);
return ByteConverter.GetString(decryptedData);
}
MemoryStream CrypStream = new MemoryStream(CiphertextData);
MemoryStream PlaiStream = new MemoryStream();
Byte[] Buffer = new Byte[MaxBlockSize];
int BlockSize = CrypStream.Read(Buffer, 0, MaxBlockSize);
while (BlockSize > 0)
{
Byte[] ToDecrypt = new Byte[BlockSize];
Array.Copy(Buffer, 0, ToDecrypt, 0, BlockSize);
Byte[] Plaintext = RSADecrypt(ToDecrypt, RSA.ExportParameters(true), false);
PlaiStream.Write(Plaintext, 0, Plaintext.Length);
BlockSize = CrypStream.Read(Buffer, 0, MaxBlockSize);
}
return ByteConverter.GetString(PlaiStream.ToArray());
}
/// <summary>
/// RSA加密
/// </summary>
/// <param name="toEncryptString">需要进行加密的字符串</param>
/// <param name="publicKey">公钥</param>
/// <returns>加密后的密文</returns>
public static string Encrypt(string toEncryptString, string publicKey)
{
UnicodeEncoding ByteConverter = new UnicodeEncoding();
byte[] dataToEncrypt = ByteConverter.GetBytes(toEncryptString);
byte[] encrytedData;
RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();
RSA.FromXmlString(publicKey);
encrytedData = RSAEncrypt(dataToEncrypt, RSA.ExportParameters(false), false);
string base64code = Convert.ToBase64String(encrytedData);
return base64code;
}
/// <summary>
/// RSA分段加密;用于对超长字符串加密
/// </summary>
/// <param name="toEncryptString">需要进行加密的字符串</param>
/// <param name="publickKey">公钥</param>
/// <returns>加密后的密文</returns>
public static string SectionEncrypt(string toEncryptString, string publickKey)
{
string base64code = string.Empty;
UnicodeEncoding ByteConverter = new UnicodeEncoding();
byte[] dataToEncrypt = ByteConverter.GetBytes(toEncryptString);
RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();
RSA.FromXmlString(publickKey);
int MaxBlockSize = RSA.KeySize / 8 - 11;
if (dataToEncrypt.Length <= MaxBlockSize)
{
byte[] encrytedData;
encrytedData = RSAEncrypt(dataToEncrypt, RSA.ExportParameters(false), false);
base64code = Convert.ToBase64String(encrytedData);
return base64code;
}
MemoryStream plaiStream = new MemoryStream(dataToEncrypt);
MemoryStream CrypStream = new MemoryStream();
Byte[] Buffer = new Byte[MaxBlockSize];
int BlockSize = plaiStream.Read(Buffer, 0, MaxBlockSize);
while (BlockSize > 0)
{
Byte[] ToEncrypt = new Byte[BlockSize];
Array.Copy(Buffer, 0, ToEncrypt, 0, BlockSize);
Byte[] Cryptograph = RSAEncrypt(ToEncrypt, RSA.ExportParameters(false), false);
CrypStream.Write(Cryptograph, 0, Cryptograph.Length);
BlockSize = plaiStream.Read(Buffer, 0, MaxBlockSize);
}
base64code = Convert.ToBase64String(CrypStream.ToArray(), Base64FormattingOptions.None);
return base64code;
}
private static byte[] RSAEncrypt(byte[] DataToEncrypt, RSAParameters RSAKeyInfo, bool DoOAEPPadding)
{
RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();
RSA.ImportParameters(RSAKeyInfo);
return RSA.Encrypt(DataToEncrypt, DoOAEPPadding);
}
private static byte[] RSADecrypt(byte[] DataToDecrypt, RSAParameters RSAKeyInfo, bool DoOAEPPadding)
{
RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();
RSA.ImportParameters(RSAKeyInfo);
return RSA.Decrypt(DataToDecrypt, DoOAEPPadding);
}
/// <summary>
/// RSA生成公钥和私钥
/// </summary>
/// <returns></returns>
public static string[] GenerateKeys()
{
try
{
string[] sKeys = new String[2];
RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
sKeys[0] = rsa.ToXmlString(true);
sKeys[1] = rsa.ToXmlString(false);
return sKeys;
}
catch (Exception)
{
return null;
}
}
}
}

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[资料] c# RSA加密解密分段加密和分段解密

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