.Net 加密 哈希

一、DES加解密

　　DES一共就有4个参数参与运作：明文、密文、密钥、向量。其中这4者的关系可以理解为：

　　密文=明文+密钥+向量；

　　明文=密文-密钥-向量；

　　为什么要向量这个参数呢？因为如果有一篇文章，有几个词重复，那么这个词加上密钥形成的密文，仍然会重复，这给破解者有机可乘，破解者可以根据重复的内容，猜出是什么词，然而一旦猜对这个词，那么，他就能算出密钥，整篇文章就被破解了！加上向量这个参数以后，每块文字段都会依次加上一段值，这样，即使相同的文字，加密出来的密文，也是不一样的，算法的安全性大大提高！

　　下面给出DES加、解密的.Net封装版：

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

namespace 开发测试
{
class Program
{
static void Main(string[] args)
{
string user = Encrypt("admin");
string pass = Encrypt("999999");

Console.WriteLine(user);
Console.WriteLine(pass);

string GetUser = Decrypt(user);
string GetPass = Decrypt(pass);

Console.WriteLine(GetUser);
Console.WriteLine(GetPass);

Console.ReadLine();
}

/// <summary>
/// 获取密钥
/// </summary>
private static string Key
{
get { return @"P@+#wG%A"; }
}

/// <summary>
/// 获取向量
/// </summary>
private static string IV
{
get { return @"L*n67}G\Mk@k%:~Y"; }
}

/// <summary>
/// DES加密
/// </summary>
/// <param name="plainStr">明文字符串</param>
/// <returns>密文</returns>
public static string Encrypt(string plainStr)
{
byte[] bKey = Encoding.UTF8.GetBytes(Key);
byte[] bIV = Encoding.UTF8.GetBytes(IV);
byte[] byteArray = Encoding.UTF8.GetBytes(plainStr);

string encrypt = null;
DESCryptoServiceProvider des = new DESCryptoServiceProvider();
try
{
using (MemoryStream mStream = new MemoryStream())
{
using (CryptoStream cStream = new CryptoStream(mStream, des.CreateEncryptor(bKey, bIV), CryptoStreamMode.Write))
{
cStream.Write(byteArray, 0, byteArray.Length);
cStream.FlushFinalBlock();
encrypt = Convert.ToBase64String(mStream.ToArray());
}
}
}
catch { }
des.Clear();
return encrypt;
}

/// <summary>
/// DES解密
/// </summary>
/// <param name="encryptStr">密文字符串</param>
/// <returns>明文</returns>
public static string Decrypt(string encryptStr)
{
byte[] bKey = Encoding.UTF8.GetBytes(Key);
byte[] bIV = Encoding.UTF8.GetBytes(IV);
byte[] byteArray = Convert.FromBase64String(encryptStr);

string decrypt = null;
DESCryptoServiceProvider des = new DESCryptoServiceProvider();
try
{
using (MemoryStream mStream = new MemoryStream())
{
using (CryptoStream cStream = new CryptoStream(mStream, des.CreateDecryptor(bKey, bIV), CryptoStreamMode.Write))
{
cStream.Write(byteArray, 0, byteArray.Length);
cStream.FlushFinalBlock();
decrypt = Encoding.UTF8.GetString(mStream.ToArray());
}
}
}
catch { }
des.Clear();
return decrypt;
}
}
}

二、AES加解密

　　AES是美国联邦政府采用的商业及政府数据加密标准，预计将在未来几十年里代替DES在各个领域中得到广泛应用。AES提供128位密钥，因此，128位AES的加密强度是56位DES加密强度的1021倍还多。假设可以制造一部可以在1秒内破解DES密码的机器，那么使用这台机器破解一个128位AES密码需要大约149亿万年的时间。

　　下面给出AES加解密的.Net封装版:

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

namespace 开发测试
{
class Program
{
static void Main(string[] args)
{
string user = Encrypt("admin");
string pass = Encrypt("999999");

Console.WriteLine(user);
Console.WriteLine(pass);

string GetUser = Decrypt(user);
string GetPass = Decrypt(pass);

Console.WriteLine(GetUser);
Console.WriteLine(GetPass);

Console.ReadLine();
}

/// <summary>
/// 获取密钥
/// </summary>
private static string Key
{
get { return @"qO[NB]6,YF}gefcaj{+oESb9d8>Z'e9M"; }
}

/// <summary>
/// 获取向量
/// </summary>
private static string IV
{
get { return @"L+\~f4.Ir)b$=pkf"; }
}

/// <summary>
/// AES加密
/// </summary>
/// <param name="plainStr">明文字符串</param>
/// <returns>密文</returns>
public static string Encrypt(string plainStr)
{
byte[] bKey = Encoding.UTF8.GetBytes(Key);
byte[] bIV = Encoding.UTF8.GetBytes(IV);
byte[] byteArray = Encoding.UTF8.GetBytes(plainStr);

string encrypt = null;
Rijndael aes = Rijndael.Create();
try
{
using (MemoryStream mStream = new MemoryStream())
{
using (CryptoStream cStream = new CryptoStream(mStream, aes.CreateEncryptor(bKey, bIV), CryptoStreamMode.Write))
{
cStream.Write(byteArray, 0, byteArray.Length);
cStream.FlushFinalBlock();
encrypt = Convert.ToBase64String(mStream.ToArray());
}
}
}
catch { }
aes.Clear();

return encrypt;
}

/// <summary>
/// AES解密
/// </summary>
/// <param name="encryptStr">密文字符串</param>
/// <returns>明文</returns>
public static string Decrypt(string encryptStr)
{
byte[] bKey = Encoding.UTF8.GetBytes(Key);
byte[] bIV = Encoding.UTF8.GetBytes(IV);
byte[] byteArray = Convert.FromBase64String(encryptStr);

string decrypt = null;
Rijndael aes = Rijndael.Create();
try
{
using (MemoryStream mStream = new MemoryStream())
{
using (CryptoStream cStream = new CryptoStream(mStream, aes.CreateDecryptor(bKey, bIV), CryptoStreamMode.Write))
{
cStream.Write(byteArray, 0, byteArray.Length);
cStream.FlushFinalBlock();
decrypt = Encoding.UTF8.GetString(mStream.ToArray());
}
}
}
catch { }
aes.Clear();

return decrypt;
}
}
}

三、MD5与SHA128、256...散列

　　MD5和SHA1散列通常被用于密码中，很多人称其为散列算法，实际上它正确应该叫做散列算法。散列是不可逆的，也就是没有了"解密"这个说法。

　　下面给出MD5与SHA128散列的.Net的System.Web快速实现版：

using System;
using System.Text;
using System.IO;

namespace 开发测试
{
class Program
{
static void Main(string[] args)
{
string user = MD5("admin");
string pass = MD5("999999");

Console.WriteLine(user);
Console.WriteLine(pass);

string user2 = SHA1("admin");
string pass2 = SHA1("999999");

Console.WriteLine(user2);
Console.WriteLine(pass2);

Console.ReadLine();
}

//32位大写MD5散列
public static string MD5(string str)
{
return System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(str, "MD5").ToUpper();
}

//大写SHA1散列
public static string SHA1(string str)
{
return System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(str, "SHA1").ToUpper();
}
}
}

　　全面版：

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

namespace 开发测试
{
class Program
{
static void Main(string[] args)
{
string user = MD5("admin");
string pass = MD5("999999");

Console.WriteLine(user);
Console.WriteLine(pass);

string user2 = SHA128("admin");
string pass2 = SHA128("999999");

Console.WriteLine(user2);
Console.WriteLine(pass2);

string user3 = SHA256("admin");
string pass3 = SHA256("999999");

Console.WriteLine(user3);
Console.WriteLine(pass3);

string user4 = SHA384("admin");
string pass4 = SHA384("999999");

Console.WriteLine(user4);
Console.WriteLine(pass4);

string user5 = SHA512("admin");
string pass5 = SHA512("999999");

Console.WriteLine(user5);
Console.WriteLine(pass5);

Console.ReadLine();
}

//16字节,128位
public static string MD5(string str)
{
byte[] buffer = Encoding.UTF8.GetBytes(str);
MD5CryptoServiceProvider MD5 = new MD5CryptoServiceProvider();
byte[] byteArr = MD5.ComputeHash(buffer);
return BitConverter.ToString(byteArr);
}

//20字节,160位
public static string SHA128(string str)
{
byte[] buffer = Encoding.UTF8.GetBytes(str);
SHA1CryptoServiceProvider SHA1 = new SHA1CryptoServiceProvider();
byte[] byteArr = SHA1.ComputeHash(buffer);
return BitConverter.ToString(byteArr);
}

//32字节,256位
public static string SHA256(string str)
{
byte[] buffer = Encoding.UTF8.GetBytes(str);
SHA256CryptoServiceProvider SHA256 = new SHA256CryptoServiceProvider();
byte[] byteArr = SHA256.ComputeHash(buffer);
return BitConverter.ToString(byteArr);
}

//48字节,384位
public static string SHA384(string str)
{
byte[] buffer = Encoding.UTF8.GetBytes(str);
SHA384CryptoServiceProvider SHA384 = new SHA384CryptoServiceProvider();
byte[] byteArr = SHA384.ComputeHash(buffer);
return BitConverter.ToString(byteArr);
}

//64字节,512位
public static string SHA512(string str)
{
byte[] buffer = Encoding.UTF8.GetBytes(str);
SHA512CryptoServiceProvider SHA512 = new SHA512CryptoServiceProvider();
byte[] byteArr = SHA512.ComputeHash(buffer);
return BitConverter.ToString(byteArr);
}
}
}