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C#的DES文件加解密工具類

C# DES文件加解密

using System;
using System.Collections.Generic;
using System.Text;
using System.Security.Cryptography;
using System.IO;

namespace www.xinduofen.com
{
class FileDES
{
///
/// 加密文件隨機數生成
///
private static RandomNumberGenerator rand = new RNGCryptoServiceProvider();

private const ulong FC_TAG = 0xFC010203040506CF;
private const int BUFFER_SIZE = 32 * 1024;

///
/// 異常內部處理類
///
private class CryptoHelpException : ApplicationException
{
public CryptoHelpException(string msg) : base(msg) { }
}

///
/// 加密文件,此方法不對異常進行處理,需要調用方進行捕獲
///
/// 待加密文件
/// 加密後輸出文件
/// 加密密碼
/// 方法未產生任何異常 - 成功
public static void EncryptFile(string inFile, string outFile, string password)
{
using (FileStream fin = File.OpenRead(inFile),
fout = File.OpenWrite(outFile))

{
// 獲取IV和salt
byte[] IV = GenerateRandomBytes(16);
byte[] salt = GenerateRandomBytes(16);

// 創建加密對象
SymmetricAlgorithm sma = FileDES.CreateRijndael(password, salt);
sma.IV = IV;

// 在輸出文件開始部分寫入IV和salt
fout.Write(IV, 0, IV.Length);
fout.Write(salt, 0, salt.Length);

// 創建散列加密
HashAlgorithm hasher = SHA256.Create();
long lSize = fin.Length; // 輸入文件長度
byte[] bytes = new byte[BUFFER_SIZE]; // 緩存
int read = -1; // 輸入文件讀取數量
int value = 0;
using (CryptoStream cout = new CryptoStream(fout, sma.CreateEncryptor(), CryptoStreamMode.Write),
chash = new CryptoStream(Stream.Null, hasher, CryptoStreamMode.Write))
{
BinaryWriter bw = new BinaryWriter(cout);
bw.Write(lSize);

bw.Write(FC_TAG);

// 讀寫字節塊到加密流緩沖區
while ((read = fin.Read(bytes, 0, bytes.Length)) != 0)
{
cout.Write(bytes, 0, read);
chash.Write(bytes, 0, read);
value += read;
}
// 關閉加密流
chash.Flush();
chash.Close();

// 讀取散列
byte[] hash = hasher.Hash;

// 輸入文件寫入散列
cout.Write(hash, 0, hash.Length);

// 關閉文件流
cout.Flush();
cout.Close();
}
}
}

///
/// 解密文件,此方法不對異常進行處理,需要調用方進行捕獲
///
/// 待解密文件
/// 解密後輸出文件
/// 解密密碼
/// 方法未產生任何異常 - 成功
public static void DecryptFile(string inFile, string outFile, string password)
{
// 創建打開文件流
using (FileStream fin = File.OpenRead(inFile),
fout = File.OpenWrite(outFile))
{
int size = (int)fin.Length;
byte[] bytes = new byte[BUFFER_SIZE];
int read = -1;
int value = 0;
int outValue = 0;

byte[] IV = new byte[16];
fin.Read(IV, 0, 16);
byte[] salt = new byte[16];
fin.Read(salt, 0, 16);

SymmetricAlgorithm sma = FileDES.CreateRijndael(password, salt);
sma.IV = IV;

value = 32;
long lSize = -1;

// 創建散列對象, 校驗文件
HashAlgorithm hasher = SHA256.Create();

using (CryptoStream cin = new CryptoStream(fin, sma.CreateDecryptor(), CryptoStreamMode.Read),
chash = new CryptoStream(Stream.Null, hasher, CryptoStreamMode.Write))
{
// 讀取文件長度
BinaryReader br = new BinaryReader(cin);
lSize = br.ReadInt64();
ulong tag = br.ReadUInt64();

if (FC_TAG != tag)
throw new CryptoHelpException("文件被破壞");

long numReads = lSize / BUFFER_SIZE;

long slack = (long)lSize % BUFFER_SIZE;

for (int i = 0; i < numReads; ++i)
{
read = cin.Read(bytes, 0, bytes.Length);
fout.Write(bytes, 0, read);
chash.Write(bytes, 0, read);
value += read;
outValue += read;
}

if (slack > 0)
{
read = cin.Read(bytes, 0, (int)slack);
fout.Write(bytes, 0, read);
chash.Write(bytes, 0, read);
value += read;
outValue += read;
}

chash.Flush();
chash.Close();

fout.Flush();
fout.Close();

byte[] curHash = hasher.Hash;

// 獲取比較和舊的散列對象
byte[] oldHash = new byte[hasher.HashSize / 8];
read = cin.Read(oldHash, 0, oldHash.Length);
if ((oldHash.Length != read) || (!CheckByteArrays(oldHash, curHash)))
throw new CryptoHelpException("文件被破壞");
}

if (outValue != lSize)
throw new CryptoHelpException("文件大小不匹配");
}
}

///
/// 創建加密對象
///
/// 密碼
/// 密鑰salt
/// 加密對象
private static SymmetricAlgorithm CreateRijndael(string password, byte[] salt)
{
PasswordDeriveBytes pdb = new PasswordDeriveBytes(password, salt, "SHA256", 1000);

SymmetricAlgorithm sma = Rijndael.Create();
sma.KeySize = 256;
sma.Key = pdb.GetBytes(32);
sma.Padding = PaddingMode.PKCS7;
return sma;
}

///
/// 檢驗兩個Byte數組是否相同
///
/// Byte數組
/// Byte數組
/// true-相等
private static bool CheckByteArrays(byte[] b1, byte[] b2)
{
if (b1.Length == b2.Length)
{
for (int i = 0; i < b1.Length; ++i)
{
if (b1[i] != b2[i])
return false;
}
return true;
}
return false;
}

///
/// 生成指定長度的隨機Byte數組
///
/// Byte數組長度
/// 隨機Byte數組
private static byte[] GenerateRandomBytes(int count)
{
byte[] bytes = new byte[count];
rand.GetBytes(bytes);
return bytes;
}

}
}
文章來自:越康體育

C#的DES文件加解密工具類