1、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！
2、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。
3、MD5和SHA1散列通常被用于密码中，很多人称其为散列算法。散列是不可逆的，也就是没有了"解密"这个说法。
des加解密参考：http://www.faceye.net/search/110023.html
加解密只是参考：http://blog.csdn.net/z1x1c1v1/article/details/8755032
using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Linq;using System.Text;using System.Windows.Forms;using System.Security.Cryptography;using System.IO;namespace WinForms_Crypt{ public partial class Form3 : Form { /// /// 加密解密方式 /// private enum CryptType { MD5,DES,AES } /// /// 当前使用的加解密方式 /// CryptType type = CryptType.MD5; public Form3() { InitializeComponent(); if (type == CryptType.MD5) { button_Decrypt.Enabled = false; button_Encrypt.Enabled = true; } else if (type == CryptType.DES) { button_Decrypt.Enabled = true; button_Encrypt.Enabled = true; } else if (type == CryptType.AES) { button_Decrypt.Enabled = true; button_Encrypt.Enabled = true; } } /// /// 加密 /// /// /// private void button_Encrypt_Click(object sender, EventArgs e) { //明文 string MingWen = textBox_DecryptText.Text.Trim(); //加密得到的密文 string MiWen = ""; if (MingWen != "") { if (type == CryptType.MD5) { MiWen = "MD5Base64："+MD5_Crypt.GetHashStr(MingWen); MiWen += "\r\n MD5：" + MD5_Crypt2.MD5(MiWen); MiWen += "\r\n SHA128：" + MD5_Crypt2.SHA128(MiWen); MiWen += "\r\n SHA256：" + MD5_Crypt2.SHA256(MiWen); MiWen += "\r\n SHA384：" + MD5_Crypt2.SHA384(MiWen); MiWen += "\r\n SHA512：" + MD5_Crypt2.SHA512(MiWen); } else if (type == CryptType.DES) { MiWen = DES_Crypt.Encrypt(MingWen); } else if (type == CryptType.AES) { MiWen = AeS_Crypt.Encrypt(MingWen); } } textBox_EncyptText.Text = MiWen; } /// /// 解密 /// /// /// private void button_Decrypt_Click(object sender, EventArgs e) { //密文 string MiWen = textBox_EncyptText.Text.Trim(); //解密得到的明文 string MingWen = ""; //无法解析哈希值 if (MiWen != "") { if (type == CryptType.MD5) { MessageBox.Show("MD5无法解密"); } else if (type == CryptType.DES) { MingWen = DES_Crypt.Decrypt(MiWen); } else if (type == CryptType.AES) { MingWen = AeS_Crypt.Decrypt(MiWen); } } textBox_DecryptText.Text = MingWen; } } /// /// MD5加密 /// public class MD5_Crypt { /// /// MD5加密 /// /// 原文 /// 加密后的字节数组 public static byte[] GetHash(byte[] inputByt) { HashAlgorithm algorithm = HashAlgorithm.Create("MD5"); return algorithm.ComputeHash(inputByt); } /// /// MD5加密 /// /// 原文 /// 加密后的字节数组 public static byte[] GetHash(string inputStr) { byte[] inputByt = new UnicodeEncoding().GetBytes(inputStr); return GetHash(inputByt); } /// /// MD5加密 /// /// 原文 /// BASE64编码字符串 public static string GetHashStr(string inputStr) { return Convert.ToBase64String(GetHash(inputStr)); } /// /// MD5加密 /// /// 原文 /// 32位编码 public static string GetHashString32(string inputStr) { string hash = BitConverter.ToString(GetHash(inputStr)); return hash.Replace("-", ""); } /// /// MD5加密 /// /// 原文 /// 32位编码 public static string GetHashString(byte[] inputStr) { string hash = BitConverter.ToString(GetHash(inputStr)); return hash.Replace("-", ""); } } /// /// DES加解密 /// public class DES_Crypt { /// /// 获取密钥 /// private static string Key { get { return @"P@+#wG%A"; } } /// /// 获取向量 /// private static string IV { get { return @"L*n67}G\Mk@k%:~Y"; } } /// /// DES加密 /// /// 明文字符串 /// 密文 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; } /// /// DES解密 /// /// 密文字符串 /// 明文 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; } } /// /// AES加解密 /// public class AeS_Crypt { /// /// 获取密钥 /// private static string Key { get { return @"qO[NB]6,YF}gefcaj{+oESb9d8>Z'e9M"; } } /// /// 获取向量 /// private static string IV { get { return @"L+\~f4.Ir)b$=pkf"; } } /// /// AES加密 /// /// 明文字符串 /// 密文 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; } /// /// AES解密 /// /// 密文字符串 /// 明文 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; } } public class MD5_Crypt2 { //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); } }}