AES 加密代码

AES 加密代码 这是从动网项目中挖出来的AES加密代码

Code

using System;

using System.Collections.Generic;

using System.Text;

namespace AES

{

public class Utils

{

/// <summary>

/// 字符串如果操过指定长度则将超出的部分用指定字符串代替

/// </summary>

/// <param name="p_SrcString">要检查的字符串</param>

/// <param name="p_Length">指定长度</param>

/// <param name="p_TailString">用于替换的字符串</param>

/// <returns>截取后的字符串</returns>

public static string GetSubString(string p_SrcString, int p_Length, string p_TailString)

{

return GetSubString(p_SrcString, 0, p_Length, p_TailString);

}

/// <summary>

/// 取指定长度的字符串

/// </summary>

/// <param name="p_SrcString">要检查的字符串</param>

/// <param name="p_StartIndex">起始位置</param>

/// <param name="p_Length">指定长度</param>

/// <param name="p_TailString">用于替换的字符串</param>

/// <returns>截取后的字符串</returns>

public static string GetSubString(string p_SrcString, int p_StartIndex, int p_Length, string p_TailString)

{

string myResult = p_SrcString;

//当是日文或韩文时(注:中文的范围:\u4e00 - \u9fa5, 日文在\u0800 - \u4e00, 韩文为\xAC00-\xD7A3)

if (System.Text.RegularExpressions.Regex.IsMatch(p_SrcString, "[\u0800-\u4e00]+") ||

System.Text.RegularExpressions.Regex.IsMatch(p_SrcString, "[\xAC00-\xD7A3]+"))

{

//当截取的起始位置超出字段串长度时

if (p_StartIndex >= p_SrcString.Length)

{

return "";

}

else

{

return p_SrcString.Substring(p_StartIndex,

((p_Length + p_StartIndex) > p_SrcString.Length) ? (p_SrcString.Length - p_StartIndex) : p_Length);

}

}

if (p_Length >= 0)

{

byte[] bsSrcString = Encoding.Default.GetBytes(p_SrcString);

//当字符串长度大于起始位置

if (bsSrcString.Length > p_StartIndex)

{

int p_EndIndex = bsSrcString.Length;

//当要截取的长度在字符串的有效长度范围内

if (bsSrcString.Length > (p_StartIndex + p_Length))

{

p_EndIndex = p_Length + p_StartIndex;

}

else

{ //当不在有效范围内时,只取到字符串的结尾

p_Length = bsSrcString.Length - p_StartIndex;

p_TailString = "";

}

int nRealLength = p_Length;

int[] anResultFlag = new int[p_Length];

byte[] bsResult = null;

int nFlag = 0;

for (int i = p_StartIndex; i < p_EndIndex; i++)

{

if (bsSrcString[i] > 127)

{

nFlag++;

if (nFlag == 3)

{

nFlag = 1;

}

}

else

{

nFlag = 0;

}

anResultFlag[i] = nFlag;

}

if ((bsSrcString[p_EndIndex - 1] > 127) && (anResultFlag[p_Length - 1] == 1))

{

nRealLength = p_Length + 1;

}

bsResult = new byte[nRealLength];

Array.Copy(bsSrcString, p_StartIndex, bsResult, 0, nRealLength);

myResult = Encoding.Default.GetString(bsResult);

myResult = myResult + p_TailString;

}

}

return myResult;

}

}

}