using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

using System.Text;
using System.Security.Cryptography;
using System.IO;
/// <summary>
///DEncrypt 的摘要說明
/// </summary>
public static class DEncrypt
{
??????? /// <summary>
??????? /// MD5函數
??????? /// </summary>
??????? /// <param name="input">原始字符串</param>
??????? /// <returns>MD5結果</returns>
??????? public static string MD5(string input)
??????? {
??????????? byte[] bytes = Encoding.UTF8.GetBytes(input);
??????????? bytes = new MD5CryptoServiceProvider().ComputeHash(bytes);
??????????? string result = string.Empty;
??????????? for (int i = 0; i < bytes.Length; i++)
??????????????? result += bytes[i].ToString("x").PadLeft(2, '0');

??????????? return result;
??????? }

??????? /// <summary>
??????? /// SHA256函數
??????? /// </summary>
??????? /// /// <param name="input">原始字符串</param>
??????? /// <returns>SHA256結果</returns>
??????? public static string SHA256(string input)
??????? {
??????????? byte[] data = Encoding.UTF8.GetBytes(input);
??????????? SHA256Managed sha256 = new SHA256Managed();
??????????? byte[] result = sha256.ComputeHash(data);
??????????? return Convert.ToBase64String(result);? //返回長度為44字節的字符串
??????? }

??????? //默認密鑰向量
??????? private static byte[] AESKeys = { 0x41, 0x72, 0x65, 0x79, 0x6F, 0x75, 0x6D, 0x79, 0x53, 0x6E, 0x6F, 0x77, 0x6D, 0x61, 0x6E, 0x3F };

??????? public static string AESEncode(string input, string key)
??????? {
??????????? key = GetSubString(key, 32, string.Empty);
??????????? key = key.PadRight(32, ' ');

??????????? RijndaelManaged rijndaelProvider = new RijndaelManaged();
??????????? rijndaelProvider.Key = Encoding.UTF8.GetBytes(key.Substring(0, 32));
??????????? rijndaelProvider.IV = AESKeys;
??????????? ICryptoTransform rijndaelEncrypt = rijndaelProvider.CreateEncryptor();

??????????? byte[] inputData = Encoding.UTF8.GetBytes(input);
??????????? byte[] encryptedData = rijndaelEncrypt.TransformFinalBlock(inputData, 0, inputData.Length);

??????????? return Convert.ToBase64String(encryptedData);
??????? }

??????? public static string AESDecode(string input, string key)
??????? {
??????????? try
??????????? {
??????????????? key = GetSubString(key, 32, string.Empty);
??????????????? key = key.PadRight(32, ' ');

??????????????? RijndaelManaged rijndaelProvider = new RijndaelManaged();
??????????????? rijndaelProvider.Key = Encoding.UTF8.GetBytes(key);
??????????????? rijndaelProvider.IV = AESKeys;
??????????????? ICryptoTransform rijndaelDecrypt = rijndaelProvider.CreateDecryptor();

??????????????? byte[] inputData = Convert.FromBase64String(input);
??????????????? byte[] decryptedData = rijndaelDecrypt.TransformFinalBlock(inputData, 0, inputData.Length);

??????????????? return Encoding.UTF8.GetString(decryptedData);
??????????? }
??????????? catch
??????????? {
??????????????? return string.Empty;
??????????? }

??????? }

??????? //默認密鑰向量
??????? private static byte[] DESKeys = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };

??????? /// <summary>
??????? /// DES加密字符串
??????? /// </summary>
??????? /// <param name="input">待加密的字符串</param>
??????? /// <param name="key">加密密鑰,要求為8位</param>
??????? /// <returns>加密成功返回加密后的字符串,失敗返回源串</returns>
??????? public static string DESEncode(string input, string key)
??????? {
??????????? key = GetSubString(key, 8, string.Empty);
??????????? key = key.PadRight(8, ' ');
??????????? byte[] rgbKey = Encoding.UTF8.GetBytes(key.Substring(0, 8));
??????????? byte[] rgbIV = DESKeys;
??????????? byte[] inputByteArray = Encoding.UTF8.GetBytes(input);
??????????? DESCryptoServiceProvider provider = new DESCryptoServiceProvider();
??????????? MemoryStream memory = new MemoryStream();
??????????? CryptoStream stream = new CryptoStream(memory, provider.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
??????????? stream.Write(inputByteArray, 0, inputByteArray.Length);
??????????? stream.FlushFinalBlock();
??????????? return Convert.ToBase64String(memory.ToArray());

??????? }

??????? /// <summary>
??????? /// DES解密字符串
??????? /// </summary>
??????? /// <param name="input">待解密的字符串</param>
??????? /// <param name="key">解密密鑰,要求為8位,和加密密鑰相同</param>
??????? /// <returns>解密成功返回解密后的字符串,失敗返源串</returns>
??????? public static string DESDecode(string input, string key)
??????? {
??????????? try
??????????? {
??????????????? key = GetSubString(key, 8, string.Empty);
??????????????? key = key.PadRight(8, ' ');
??????????????? byte[] rgbKey = Encoding.UTF8.GetBytes(key);
??????????????? byte[] rgbIV = DESKeys;
??????????????? byte[] inputByteArray = Convert.FromBase64String(input);
??????????????? DESCryptoServiceProvider provider = new DESCryptoServiceProvider();

??????????????? MemoryStream memory = new MemoryStream();
??????????????? CryptoStream stream = new CryptoStream(memory, provider.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
??????????????? stream.Write(inputByteArray, 0, inputByteArray.Length);
??????????????? stream.FlushFinalBlock();
??????????????? return Encoding.UTF8.GetString(memory.ToArray());
??????????? }
??????????? catch
??????????? {
??????????????? return string.Empty;
??????????? }
??????? }

??????? public static string GetSubString(string input, int length, string pad)
??????? {
??????????? return GetSubString(input, 0, length, pad);
??????? }

??????? /// <summary>
??????? /// 取指定長度的字符串
??????? /// </summary>
??????? /// <param name="input">要檢查的字符串</param>
??????? /// <param name="start">起始位置</param>
??????? /// <param name="length">指定長度</param>
??????? /// <param name="pad">用于替換的字符串</param>
??????? /// <returns>截取后的字符串</returns>
??????? public static string GetSubString(string input, int start, int length, string pad)
??????? {
??????????? string result = input;

??????????? Byte[] comments = Encoding.UTF8.GetBytes(input);
??????????? foreach (char c in Encoding.UTF8.GetChars(comments))
??????????? {??? //當是日文或韓文時(注:中文的范圍:\u4e00 - \u9fa5, 日文在\u0800 - \u4e00, 韓文為\xAC00-\xD7A3)
??????????????? if ((c > '\u0800' && c < '\u4e00') || (c > '\xAC00' && c < '\xD7A3'))
??????????????? {
??????????????????? //if (System.Text.RegularExpressions.Regex.IsMatch(p_SrcString, "[\u0800-\u4e00]+") || System.Text.RegularExpressions.Regex.IsMatch(p_SrcString, "[\xAC00-\xD7A3]+"))
??????????????????? //當截取的起始位置超出字段串長度時
??????????????????? if (start >= input.Length)
??????????????????????? return string.Empty;
??????????????????? else
??????????????????????? return input.Substring(start, ((length + start) > input.Length) ? (input.Length - start) : length);
??????????????? }
??????????? }

??????????? if (length >= 0)
??????????? {
??????????????? byte[] bytes = Encoding.Default.GetBytes(input);

??????????????? //當字符串長度大于起始位置
??????????????? if (bytes.Length > start)
??????????????? {
??????????????????? int stopIndex = bytes.Length;

??????????????????? //當要截取的長度在字符串的有效長度范圍內
??????????????????? if (bytes.Length > (start + length))
??????????????????? {
??????????????????????? stopIndex = length + start;
??????????????????? }
??????????????????? else
??????????????????? {?? //當不在有效范圍內時,只取到字符串的結尾

??????????????????????? length = bytes.Length - start;
??????????????????????? pad = string.Empty;
??????????????????? }

??????????????????? int realLength = length;
??????????????????? int[] resultFlag = new int[length];
??????????????????? byte[] byteResult = null;

??????????????????? int flag = 0;
??????????????????? for (int i = start; i < stopIndex; i++)
??????????????????? {
??????????????????????? if (bytes[i] > 127)
??????????????????????? {
??????????????????????????? flag++;
??????????????????????????? if (flag == 3)
??????????????????????????????? flag = 1;
??????????????????????? }
??????????????????????? else
??????????????????????????? flag = 0;

??????????????????????? resultFlag[i] = flag;
??????????????????? }

??????????????????? if ((bytes[stopIndex - 1] > 127) && (resultFlag[length - 1] == 1))
??????????????????????? realLength = length + 1;

??????????????????? byteResult = new byte[realLength];

??????????????????? Array.Copy(bytes, start, byteResult, 0, realLength);

??????????????????? result = Encoding.Default.GetString(byteResult);
??????????????????? result = result + pad;
??????????????? }
??????????? }

??????????? return result;
??????? }
??? }

轉載于:https://www.cnblogs.com/janneystory/archive/2013/04/11/3014558.html

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