using System;
using System.IO;
using System.Security;
using System.Security.Cryptography;
using System.Runtime.InteropServices;
using System.Text;

namespace YNEC.Services.Encrypt {
/**//// <summary>
/// CRC 效验
/// 快速检测算法
/// </summary>
public class CRC32{

protected ulong[] crc32Table;

/**//// <summary>
/// 构造：初始化效验表
/// </summary>
public CRC32() {
const ulong ulPolynomial = 0xEDB88320;
ulong dwCrc;
crc32Table = new ulong[256];
int i,j;
for(i = 0; i < 256; i++) {
dwCrc = (ulong)i;
for(j = 8; j > 0; j--) {
if((dwCrc & 1)==1)
dwCrc = (dwCrc >> 1) ^ ulPolynomial;
else
dwCrc >>= 1;
}
crc32Table[i] = dwCrc;
}
}

/**//// <summary>
/// 字节数组效验
/// </summary>
/// <param name="buffer">ref 字节数组</param>
/// <returns></returns>
public ulong ByteCRC(ref byte[] buffer) {
ulong ulCRC = 0xffffffff;
ulong len;
len = (ulong)buffer.Length;
for (ulong buffptr=0; buffptr < len; buffptr++) {
ulong tabPtr = ulCRC & 0xFF;
tabPtr = tabPtr ^ buffer[buffptr];
ulCRC = ulCRC >> 8;
ulCRC = ulCRC ^ crc32Table[tabPtr];
}
return ulCRC ^ 0xffffffff;
}


/**//// <summary>
/// 字符串效验
/// </summary>
/// <param name="sInputString">字符串</param>
/// <returns></returns>
public ulong StringCRC(string sInputString){
byte[] buffer = Encoding.Default.GetBytes(sInputString);
return ByteCRC(ref buffer);
}

/**//// <summary>
/// 文件效验
/// </summary>
/// <param name="sInputFilename">输入文件</param>
/// <returns></returns>
public ulong FileCRC(string sInputFilename){
FileStream inFile = new System.IO.FileStream(sInputFilename, System.IO.FileMode.Open, System.IO.FileAccess.Read);
byte[] bInput = new byte[inFile.Length];
inFile.Read(bInput,0,bInput.Length);
inFile.Close();

return ByteCRC(ref bInput);
}

}
/**//// <summary>
/// MD5 无逆向编码
/// 获取唯一特征串，可用于密码加密
/// (无法还原)
/// </summary>
public class MD5 {

public MD5(){
}

/**//// <summary>
/// 获取字符串的特征串
/// </summary>
/// <param name="sInputString">输入文本</param>
/// <returns></returns>
public string HashString(string sInputString){
System.Security.Cryptography.MD5 md5 = System.Security.Cryptography.MD5.Create();
string encoded = BitConverter.ToString(md5.ComputeHash(Encoding.Default.GetBytes(sInputString))).Replace("-","");
return encoded;
}

/**//// <summary>
/// 获取文件的特征串
/// </summary>
/// <param name="sInputFilename">输入文件</param>
/// <returns></returns>
public string HashFile(string sInputFilename){
System.Security.Cryptography.MD5 md5 = System.Security.Cryptography.MD5.Create();
FileStream inFile = new System.IO.FileStream(sInputFilename, System.IO.FileMode.Open, System.IO.FileAccess.Read);
byte[] bInput = new byte[inFile.Length];
inFile.Read(bInput,0,bInput.Length);
inFile.Close();

string encoded = BitConverter.ToString(md5.ComputeHash(bInput)).Replace("-","");
return encoded;
}

}

/**//// <summary>
/// Base64 UUEncoded 编码
/// 将二进制编码为ASCII文本，用于网络传输
/// (可还原)
/// </summary>
public class BASE64{

public BASE64(){
}

/**//// <summary>
/// 解码字符串
/// </summary>
/// <param name="sInputString">输入文本</param>
/// <returns></returns>
public string DecryptString(string sInputString){
char[] sInput = sInputString.ToCharArray();
try{
byte[] bOutput = System.Convert.FromBase64String(sInputString);
return Encoding.Default.GetString(bOutput);
}
catch ( System.ArgumentNullException ) {
//base 64 字符数组为null
return "";
}
catch ( System.FormatException ) {
//长度错误，无法整除4
return "";
}
}

/**//// <summary>
/// 编码字符串
/// </summary>
/// <param name="sInputString">输入文本</param>
/// <returns></returns>
public string EncryptString(string sInputString){
byte[] bInput = Encoding.Default.GetBytes(sInputString);
try {
return System.Convert.ToBase64String(bInput,0,bInput.Length);
}
catch (System.ArgumentNullException) {
//二进制数组为NULL.
return "";
}
catch (System.ArgumentOutOfRangeException) {
//长度不够
return "";
}
}

/**//// <summary>
/// 解码文件
/// </summary>
/// <param name="sInputFilename">输入文件</param>
/// <param name="sOutputFilename">输出文件</param>
public void DecryptFile(string sInputFilename,string sOutputFilename) {
System.IO.StreamReader inFile;
char[] base64CharArray;

try {
inFile = new System.IO.StreamReader(sInputFilename,
System.Text.Encoding.ASCII);
base64CharArray = new char[inFile.BaseStream.Length];
inFile.Read(base64CharArray, 0, (int)inFile.BaseStream.Length);
inFile.Close();
}
catch {//(System.Exception exp) {
return;
}

// 转换Base64 UUEncoded为二进制输出
byte[] binaryData;
try {
binaryData =
System.Convert.FromBase64CharArray(base64CharArray,
0,
base64CharArray.Length);
}
catch ( System.ArgumentNullException ) {
//base 64 字符数组为null
return;
}
catch ( System.FormatException ) {
//长度错误，无法整除4
return;
}

// 写输出数据
System.IO.FileStream outFile;
try {
outFile = new System.IO.FileStream(sOutputFilename,
System.IO.FileMode.Create,
System.IO.FileAccess.Write);
outFile.Write(binaryData, 0, binaryData.Length);
outFile.Close();
}
catch{// (System.Exception exp) {
//流错误
}

}

/**//// <summary>
/// 编码文件
/// </summary>
/// <param name="sInputFilename">输入文件</param>
/// <param name="sOutputFilename">输出文件</param>
public void EncryptFile(string sInputFilename,string sOutputFilename){

System.IO.FileStream inFile;
byte[] binaryData;

try {
inFile = new System.IO.FileStream(sInputFilename,
System.IO.FileMode.Open,
System.IO.FileAccess.Read);
binaryData = new Byte[inFile.Length];
long bytesRead = inFile.Read(binaryData, 0,
(int) inFile.Length);
inFile.Close();
}
catch { //(System.Exception exp) {
return;
}

// 转换二进制输入为Base64 UUEncoded输出
// 每3个字节在源数据里作为4个字节
long arrayLength = (long) ((4.0d/3.0d) * binaryData.Length);

// 如果无法整除4
if (arrayLength % 4 != 0) {
arrayLength += 4 - arrayLength % 4;
}

char[] base64CharArray = new char[arrayLength];
try {
System.Convert.ToBase64CharArray(binaryData,
0,
binaryData.Length,
base64CharArray,
0);
}
catch (System.ArgumentNullException) {
//二进制数组为NULL.
return;
}
catch (System.ArgumentOutOfRangeException) {
//长度不够
return;
}

// 写UUEncoded数据到文件内
System.IO.StreamWriter outFile;
try {
outFile = new System.IO.StreamWriter(sOutputFilename,
false,
System.Text.Encoding.ASCII);
outFile.Write(base64CharArray);
outFile.Close();
}
catch{// (System.Exception exp) {
//文件流出错
}


}
}
/**//// <summary>
/// DES 加密
/// 支持Key(钥匙)加密变化
/// 支持还原
///
/// 演示操作：
/// // 64位，8个字节
/// string sSecretKey;
///
/// // 获取Key
/// sSecretKey = GenerateKey();
///
/// // 托管
/// GCHandle gch = GCHandle.Alloc( sSecretKey,GCHandleType.Pinned );
///
/// // 加密文件
/// EncryptFile(@"C:\MyData.txt",
/// @"C:\Encrypted.txt",
/// sSecretKey);
///
/// // 解密文件
/// DecryptFile(@"C:\Encrypted.txt",
/// @"C:\Decrypted.txt",
/// sSecretKey);
///
/// // 释放托管内容
/// ZeroMemory(gch.AddrOfPinnedObject(), sSecretKey.Length * 2);
/// gch.Free();
/// </summary>
public class DES {
[DllImport("KERNEL32.DLL", EntryPoint="RtlZeroMemory")]
public static extern bool ZeroMemory(IntPtr Destination, int Length);

public DES() {
//
// TODO: 在此处添加构造函数逻辑
//
}

/**//// <summary>
/// 创建Key
/// </summary>
/// <returns></returns>
public string GenerateKey() {
// 创建一个DES 算法的实例。自动产生Key
DESCryptoServiceProvider desCrypto =(DESCryptoServiceProvider)DESCryptoServiceProvider.Create();

// 返回自动创建的Key 用于加密
return ASCIIEncoding.ASCII.GetString(desCrypto.Key);
}

/**//// <summary>
/// 加密字符串
/// </summary>
/// <param name="sInputString">输入字符</param>
/// <param name="sKey">Key</param>
/// <returns>加密结果</returns>
public string EncryptString(string sInputString,string sKey){
byte[] data = Encoding.Default.GetBytes(sInputString);
byte[] result;
DESCryptoServiceProvider DES = new DESCryptoServiceProvider();
DES.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
DES.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
ICryptoTransform desencrypt = DES.CreateEncryptor();
result = desencrypt.TransformFinalBlock(data,0,data.Length);

string desString = "";
for(int i=0;i<result.Length;i++){
desString += result[i].ToString() + "-";
}

//return desString.TrimEnd('-');
return BitConverter.ToString(result);
}

/**//// <summary>
/// 解密字符串
/// </summary>
/// <param name="sInputString">输入字符</param>
/// <param name="sKey">Key</param>
/// <returns>解密结果</returns>
public string DecryptString(string sInputString,string sKey){
string[] sInput = sInputString.Split("-".ToCharArray());
byte[] data = new byte[sInput.Length];
byte[] result;
for(int i=0;i<sInput.Length;i++)
data[i] = byte.Parse(sInput[i],System.Globalization.NumberStyles.HexNumber);

DESCryptoServiceProvider DES = new DESCryptoServiceProvider();
DES.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
DES.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
ICryptoTransform desencrypt = DES.CreateDecryptor();
result = desencrypt.TransformFinalBlock(data,0,data.Length);
return Encoding.Default.GetString(result);
}

/**//// <summary>
/// 加密文件
/// </summary>
/// <param name="sInputFilename">输入文件</param>
/// <param name="sOutputFilename">输出文件</param>
/// <param name="sKey">Key</param>
public void EncryptFile(string sInputFilename,
string sOutputFilename,
string sKey) {
FileStream fsInput = new FileStream(sInputFilename,
FileMode.Open,
FileAccess.Read);

FileStream fsEncrypted = new FileStream(sOutputFilename,
FileMode.Create,
FileAccess.Write);
DESCryptoServiceProvider DES = new DESCryptoServiceProvider();
DES.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
DES.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
ICryptoTransform desencrypt = DES.CreateEncryptor();
CryptoStream cryptostream = new CryptoStream(fsEncrypted,
desencrypt,
CryptoStreamMode.Write);

byte[] bytearrayinput = new byte[fsInput.Length];
fsInput.Read(bytearrayinput, 0, bytearrayinput.Length);
cryptostream.Write(bytearrayinput, 0, bytearrayinput.Length);
cryptostream.Close();
fsInput.Close();
fsEncrypted.Close();
}

/**//// <summary>
/// 解密文件
/// </summary>
/// <param name="sInputFilename">输入文件</param>
/// <param name="sOutputFilename">输出文件</param>
/// <param name="sKey">Key</param>
public void DecryptFile(string sInputFilename,
string sOutputFilename,
string sKey) {
DESCryptoServiceProvider DES = new DESCryptoServiceProvider();
DES.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
DES.IV = ASCIIEncoding.ASCII.GetBytes(sKey);

FileStream fsread = new FileStream(sInputFilename,
FileMode.Open,
FileAccess.Read);
ICryptoTransform desdecrypt = DES.CreateDecryptor();
CryptoStream cryptostreamDecr = new CryptoStream(fsread,
desdecrypt,
CryptoStreamMode.Read);
StreamWriter fsDecrypted = new StreamWriter(sOutputFilename);
fsDecrypted.Write(new StreamReader(cryptostreamDecr).ReadToEnd());
fsDecrypted.Flush();
fsDecrypted.Close();
}

}
}

本文转自suifei博客园博客，原文链接http://www.cnblogs.com/Chinasf/archive/2005/05/18/157910.html，如需转载请自行联系原作者