加密&解密

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.IO;
using System.Security;
using System.Security.Cryptography;

namespace Lock_UnLock
...{
    public partial class Form1 : Form
    ...{
        

        public Form1()
        ...{
            InitializeComponent();
        }

        private byte[] sKey;
        private byte[] sIV;

        public string key = "";

        private void button5_Click(object sender, EventArgs e)
        ...{
            Application.Exit();
        }

        private void Form1_Load(object sender, EventArgs e)
        ...{
            this.textBox1.ReadOnly = true;
            this.textBox2.ReadOnly = true;
            this.radioButton1.Checked = true;
            this.label4.Text = DateTime.Now.ToLongDateString();
            this.textBox3.Text = "安全密匙用於解密文件!";
            this.textBox3.Focus();
            int len = textBox3.Text.Length;
            this.textBox3.SelectionStart = 0;
            this.textBox3.SelectionLength = len;
        }

        private void button1_Click(object sender, EventArgs e)
        ...{
            this.openFileDialog1.ShowDialog();
            string filename = openFileDialog1.FileName;
            int i = filename.LastIndexOf(".");
            if (i != -1)
            ...{
                string filetype = filename.Substring(filename.LastIndexOf("."));
                if (this.radioButton1.Checked)
                ...{
                    filename = filename.Replace("(解密文件)", "");
                    textBox2.Text = filename.Substring(0, filename.LastIndexOf(".")) + "(加密文件)" + filetype;
                }
                else
                ...{
                    filename = filename.Replace("(加密文件)", "");
                    textBox2.Text = filename.Substring(0, filename.LastIndexOf(".")) + "(解密文件)" + filetype;

                }
            }
            if (filename != "")
            ...{
                textBox1.Text = openFileDialog1.FileName;

            }
        }

        private void button2_Click(object sender, EventArgs e)
        ...{
            this.saveFileDialog1.ShowDialog();
            if (saveFileDialog1.FileName != "")
            ...{
                this.textBox2.Text = saveFileDialog1.FileName;
            }
        }

        private void radioButton1_CheckedChanged(object sender, EventArgs e)
        ...{
            if (radioButton1.Checked == true)
            ...{
                this.button4.Enabled = false;
                this.button3.Enabled = true;
            }
        }

        private void radioButton2_CheckedChanged(object sender, EventArgs e)
        ...{
            if (radioButton2.Checked == true)
            ...{
                this.button3.Enabled = false;
                this.button4.Enabled = true;
            }
        }

        "加密方法#region "加密方法
        public bool EncryptFile(string filePath, string savePath, string keyStr)
        ...{
            key = this.textBox3.Text;
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            if (keyStr == "")
                keyStr = key;
            FileStream fs = File.OpenRead(filePath);
            byte[] inputByteArray = new byte[fs.Length];
            fs.Read(inputByteArray, 0, (int)fs.Length);
            fs.Close();
            byte[] keyByteArray = Encoding.Default.GetBytes(keyStr);
            SHA1 ha = new SHA1Managed();
            byte[] hb = ha.ComputeHash(keyByteArray);
            sKey = new byte[8];
            sIV = new byte[8];
            for (int i = 0; i < 8; i++)
                sKey[i] = hb[i];
            for (int i = 8; i < 16; i++)
                sIV[i - 8] = hb[i];
            des.Key = sKey;
            des.IV = sIV;
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();
            fs = File.OpenWrite(savePath);

            foreach (byte b in ms.ToArray())
            ...{
                fs.WriteByte(b);

            }
            fs.Close();
            cs.Close();
            ms.Close();
            return true;
        }
        #endregion


        "解密方法#region "解密方法
        public bool DecryptFile(string filePath,string savePath,string keyStr) 
        ...{
            key = this.textBox3.Text;
            DESCryptoServiceProvider des = new DESCryptoServiceProvider(); 
            if(keyStr=="") 
                keyStr=key; 
            FileStream fs=File.OpenRead(filePath); 
            byte[] inputByteArray =new byte[fs.Length]; 
            fs.Read(inputByteArray,0,(int)fs.Length); 
            fs.Close(); 
            byte[] keyByteArray=Encoding.Default.GetBytes(keyStr); 
            SHA1 ha=new SHA1Managed(); 
            byte[] hb=ha.ComputeHash(keyByteArray); 
            sKey=new byte[8]; 
            sIV=new byte[8]; 
            for(int i=0;i<8;i++) 
                sKey[i]=hb[i]; 
            for(int i=8;i<16;i++) 
                sIV[i-8]=hb[i]; 
            des.Key=sKey; 
            des.IV=sIV; 
            MemoryStream ms = new MemoryStream(); 
            CryptoStream cs = new CryptoStream(ms,des.CreateDecryptor(),CryptoStreamMode.Write); 
            cs.Write(inputByteArray, 0, inputByteArray.Length); 
            cs.FlushFinalBlock(); 
            fs=File.OpenWrite(savePath); 
            foreach(byte b in ms.ToArray()) 
            ...{ 
                fs.WriteByte(b); 
            } 
            fs.Close(); 
            cs.Close(); 
            ms.Close(); 
            return true; 
        } 
        #endregion


        "加密#region "加密
        private void button3_Click(object sender, EventArgs e)
        ...{
            if (this.textBox1.Text!="" && this.textBox2.Text!="" && this.textBox3.Text!="")
            ...{
                key = this.textBox3.Text;
                this.label5.Text = "正在加密,請稍等...";
                if ((EncryptFile(this.textBox1.Text, this.textBox2.Text, key)))
                ...{
                    this.label5.Text = "加密完成。";
                    MessageBox.Show("加密成功！");
                    this.textBox1.Text = "";
                    this.textBox2.Text = "";
                    this.textBox3.Text = "";
                }
                this.label5.Visible = false;
            }
            else
            ...{
                MessageBox.Show("請輸入完整數據!");
            }
        }
        #endregion


        "解密#region "解密
        private void button4_Click(object sender, EventArgs e)
        ...{
            key = this.textBox3.Text;
            try
            ...{
                if (this.textBox1.Text != "" && this.textBox2.Text != "" && this.textBox3.Text != "")
                ...{
                    this.label5.Text = "正在解密,請稍等...";
                    if (DecryptFile(this.textBox1.Text, this.textBox2.Text, key))
                    ...{
                        this.label5.Text = "解密完成。";
                        MessageBox.Show("解密成功！");
                        this.textBox1.Text = "";
                        this.textBox2.Text = "";
                        this.textBox3.Text = "";
                    }
                    this.label5.Visible = false;
                }
                else
                ...{
                    MessageBox.Show("請輸入完整數據!");
                }
            }
            catch (Exception)
            ...{
                MessageBox.Show("解密失敗!請確認是否輸入了正確的安全密匙.");
                this.textBox3.Text = "";
            }
        }
        #endregion
    }
}