- public class LSBSteganography
- {
- private String imgUrl;
- private String password;
- private byte[] infoText;
- private byte[] imgByte;
- private const int CB = 55; //CheckBegin 隐写检测的起始下标
- private const int LB = 103; //LengthBegin 隐写文本长度的起始下标
- private const int TB = 135; //TextBegin 隐写正文的起始下标
-
- public LSBSteganography(String imgUrl, String infoText, String password)
- {
- this.imgUrl = imgUrl; //获取图片URL
- this.password = (password + "tmppwd").Substring(0, 6); //设置密码不足补齐6位,多的只取6位
- this.infoText = Encoding.Default.GetBytes(infoText); //获取隐写文本
- FileStream tFS = new FileStream(imgUrl, FileMode.Open, FileAccess.ReadWrite);
- this.imgByte = new byte[tFS.Length];
- tFS.Read(imgByte, 0, Convert.ToInt32(tFS.Length)); //把图片信息存入imgByte
- tFS.Close();
- }
-
- public String GetImgUrl()
- {
- return imgUrl; //返回图片URL
- }
-
- public String GetInfoText()
- {
- return Encoding.Default.GetString(infoText); //返回隐写信息 用户在提取信息后显示信息
- }
-
- public String LSBWrite()
- {
- try
- {
- //TB开始是真正开始隐写数据 一字节数据需要8字节图片信息来隐写
- if (imgByte.Length < infoText.Length * 8 + TB) return "写入信息失败.\n图片过小无法存入全部信息";
- this.SetCheckLSB(); //写入隐写标记 此处既是密码
- this.SetLength(); //写入隐写长度
- this.WriteInfo(); //写入文本信息
- File.WriteAllBytes(imgUrl, imgByte);
-
- return "写入信息成功.";
- }
- catch(Exception ex)
- {
- return "写入信息失败.\n" + ex.Message;
- }
- }
-
- public String LSBRead()
- {
- try
- {
- //检查输入的密码是否正确
- if (!this.CheckLSB()) return "读取信息失败.\n密码错误,或者图片不含隐藏信息.";
- this.ReadInfo(); //读取信息到infoText
- return "读取信息成功.";
- }
- catch(Exception ex)
- {
- return "读取信息失败.\n" + ex.Message;
- }
- }
-
- public String LSBClear()
- {
- try
- {
- this.ClearInfo(); //擦除信息 此处方法为无脑全部置0
- File.WriteAllBytes(imgUrl, imgByte);
- return "擦除信息成功.";
- }
- catch (Exception ex)
- {
- return "擦除信息失败.\n" + ex.Message;
- }
- }
-
- private void SetCheckLSB() //隐写密码,用于检测是否有隐写信息
- {
- byte[] checkStr = Encoding.Default.GetBytes(password);
- for (int i = 0; i < 6; i++) //6个字符
- {
- for (int j = 0; j < 8; j++) //每个字符8位
- {
- imgByte[i * 8 + j + CB] &= ((1 << 8) - 2);
- if ((checkStr[i] & (1 << j)) != 0)
- imgByte[i * 8 + j + CB]++;
- }
- }
- }
-
- private bool CheckLSB() //读取隐写密码,于用户输入密码匹配
- {
- byte[] checkStr = new byte[6];
- for (int i = 0; i < 6; i++) checkStr[i] = 0;
-
- for (int i = 0; i < 6; i++) //6个字符
- {
- for (int j = 0; j < 8; j++) //每个字符8位
- {
- if ((imgByte[i * 8 + j + CB] & 1) != 0)
- checkStr[i] |= Convert.ToByte(1 << j);
- }
- }
-
- return Encoding.Default.GetString(checkStr) == password;
- }
-
- private int GetLength() //获取隐写文本长度
- {
- int length = 0;
- for (int i = 0; i < 32; i++) //一个int 32位
- {
- if ((imgByte[i + LB] & 1) != 0)
- length |= Convert.ToByte(1 << i);
- }
-
- return length;
- }
-
- private void SetLength() //写入隐写文本长度
- {
- int length = this.infoText.Length;
- for (int i = 0; i < 32; i++) //一个int 32位
- {
- imgByte[i + LB] &= ((1 << 8) - 2); //末尾置0
- if ((length & (1 << i)) != 0)
- imgByte[i + LB]++; //如果不是0 改为1
- }
- }
-
- private void WriteInfo()
- {
- for (int i = 0; i < infoText.Length; i++)
- {
- for (int j = 0; j < 8; j++) //每个字符8位
- {
- imgByte[i * 8 + j + TB] &= ((1 << 8) - 2); //末尾置0
- if ((infoText[i] & (1 << j)) != 0)
- imgByte[i * 8 + j + TB]++; //如果不是0 改为1
- }
- }
- }
-
- private void ReadInfo()
- {
- int length = this.GetLength();
- infoText = new byte[length];
- for (int i = 0; i < length; i++)
- {
- for (int j = 0; j < 8; j++) //每个字符8位
- {
- if ((imgByte[i * 8 + j + TB] & 1) != 0)
- infoText[i] |= Convert.ToByte(1 << j);
- }
- }
- }
-
- private void ClearInfo()
- {
- int length = imgByte.Length;
- for (int i = CB; i < length; i++)
- {
- imgByte[i] &= ((1 << 8) - 2); //末尾全部置0
- }
- }
- }
|
|
收藏
淘帖
踩
