c#使用AES对媒体文件的加密与解密 - 好文

需求是媒体文件，保留头部，加密文件的BODY，所以要定位文件头，并且要有由buffer进行大文件的处理。

[C#]代码
using System.Text; using System.Collections; using System.ComponentModel; using
System.Data; using System.Net; using System.Net.Sockets; using System.Threading;
using System.IO; using System.Security.Cryptography; public class AESEncryption
{ static string strKey="dongbinhuiasxiny";//密钥,128位，也可以改为192位（24字节）或256位（32字节）。
static void Main(string[] args) { RijndaelManaged rij = new RijndaelManaged();
rij.KeySize = 128;//指定密钥长度 string fp = @"...";//待加密文件 string sPhysicalFilePath =
@"...";//加密后的文件 string fw = @"...";//解密后的文件 Console.WriteLine("Encrypting
begin..."); encryption(rij, fp, sPhysicalFilePath); decryption(rij,
sPhysicalFilePath,fw); } //用于加密的函数 public static void encryption(RijndaelManaged
rij,string readfile, string writefile) { try { //byte[] key = rij.Key; byte[]
key=Encoding.UTF8.GetBytes (strKey); byte[] iv = rij.IV; byte[] buffer = new
byte[4096]; Rijndael crypt = Rijndael.Create(); ICryptoTransform transform =
crypt.CreateEncryptor(key, iv); //写进文件 FileStream fswrite = new FileStream(
writefile, FileMode.Create); CryptoStream cs = new CryptoStream(fswrite,
transform, CryptoStreamMode.Write); //打开文件 FileStream fsread = new FileStream(
readfile, FileMode.Open); /*------------------定位要加密的部分-----------------*/ long
_file_size=fsread.Length; byte[] _header = new byte[8]; //定位GUID fsread.Seek(16,
SeekOrigin.Begin); //读取header size fsread.Read(_header, 0, _header.Length);
//头部长度 long _header_size = (long)BitConverter.ToInt32(_header, 0); byte[]
_header_buffer=new byte[_header_size]; fsread.Seek(0,SeekOrigin.Begin); fsread.
Read(_header_buffer,0,_header_buffer.Length); //头部写入新文件 fswrite.Write(
_header_buffer,0,_header_buffer.Length); //定位到头部，准备读取需要加密的部分 fsread.Seek(
_header_size,SeekOrigin.Begin); /*-----------------定位加密部分完成-------------------*/
int length; //while ((length = fsread.ReadByte()) != -1)
//cs.WriteByte((byte)length); while ((length = fsread.Read(buffer, 0, 4096)) > 0
){ cs.Write(buffer, 0, (int)length); } fsread.Close(); cs.Close(); fswrite.Close
(); Console.WriteLine("Encrypt Success"); } catch (Exception e) { Console.
WriteLine("Encrypt Faile"+e.ToString()); } } //用于解密的函数 public static void
decryption(RijndaelManaged rij, string readfile, string writefile) { try {
//byte[] key = rij.Key; byte[] key=Encoding.UTF8.GetBytes (strKey); byte[] iv =
rij.IV; byte[] buffer=new byte[4096]; Rijndael crypt = Rijndael.Create();
ICryptoTransform transform = crypt.CreateDecryptor(key, iv); //读取加密后的文件
FileStream fsopen = new FileStream(readfile, FileMode.Open); CryptoStream cs =
new CryptoStream(fsopen, transform, CryptoStreamMode.Read); //把解密后的结果写进文件
FileStream fswrite = new FileStream(writefile, FileMode.OpenOrCreate);
/*------------------定位要解密的部分-----------------*/ long _file_size=fsopen.Length;
byte[] _header = new byte[8]; //定位GUID fsopen.Seek(16, SeekOrigin.Begin);
//读取header size fsopen.Read(_header, 0, _header.Length); //头部长度 long
_header_size= (long)BitConverter.ToInt32(_header, 0); byte[] _header_buffer=new
byte[_header_size]; fsopen.Seek(0,SeekOrigin.Begin); fsopen.Read(_header_buffer,
0,_header_buffer.Length); //头部写入新文件 fswrite.Write(_header_buffer,0,
_header_buffer.Length); //定位到头部，准备读取需要加密的部分 fsopen.Seek(_header_size,SeekOrigin.
Begin); /*-----------------定位要解密的部分完成-------------------*/ int length; //while
((length = cs.ReadByte()) != -1) //fswrite.WriteByte((byte)length); while ((
length= cs.Read(buffer, 0, 4096)) > 0){ fswrite.Write(buffer, 0, (int)length); }
fswrite.Close(); cs.Close(); fsopen.Close(); Console.WriteLine("Decrypt
Success"); } catch (Exception e) { Console.WriteLine("Decrypt Failed"+e.ToString
()); } } }

热门工具换一换