我在学校里学到了DES是如何工作的，我想创建一个应用程序，就像我学习它一样。
我设法加密和解密（获取各种奇怪的符号）但我从未设法解密我的加密文件。这就是为什么我正在寻找一个好的例子，但似乎找不到一个。
您是否知道一个很好的示例项目，它在不使用.NET框架中的任何内置库的情况下执行DES？或许你想看看我的，看你能不能发现我做错了什么？
任何帮助将不胜感激，谢谢！
我加密的文字：Dit是een test te te kijken wat de uitkomst zal zijn！ 加密文字：
Aб§.ŒœwNÜúÈúÛü¿áX¯fMå©
MËà>
¹ðLþa‚@šu
ñZ…U‚¬pÃ;¯ <- white spaces (added block)
解密文字：붿뿯붿塐뿯붿礷䨟ꛝ뿯榽뿯붿湵뿯⺽뿯綽붿뿯붿雟ḝ뿯厽㼆붿붿뿯붿붿뿯붿뿯梽뿯Ⓗ⭑붿붿뿯붿뿯붿뿯碽붿⁅
使用密码：steutels van acht tekens
答案 0 :(得分：1)
代码项目有一个很好的article，它应该包含你需要的一切。
以下是文章中的完整代码：
namespace SDES_Project
{
class SDES
{
BitArray[,] S_Box1 = new BitArray[4, 4];
BitArray[,] S_Box2 = new BitArray[4, 4];
BitArray Master_key;
public SDES(string _key)
{
Master_key = new BitArray(10);
for (int i = 0; i < _key.Length; i++)
{
Master_key[i] = str2bin(_key[i]);
}
BitArray b0 = new BitArray(2);
b0[0] = false;
b0[1] = false;
BitArray b1 = new BitArray(2);
b1[0] = false;
b1[1] = true;
BitArray b2 = new BitArray(2);
b2[0] = true;
b2[1] = false;
BitArray b3 = new BitArray(2);
b3[0] = true;
b3[1] = true;
S_Box1[0, 0] = b1;
S_Box1[0, 1] = b0;
S_Box1[0, 2] = b3;
S_Box1[0, 3] = b2;
S_Box1[1, 0] = b3;
S_Box1[1, 1] = b2;
S_Box1[1, 2] = b1;
S_Box1[1, 3] = b0;
S_Box1[2, 0] = b0;
S_Box1[2, 1] = b2;
S_Box1[2, 2] = b1;
S_Box1[2, 3] = b3;
S_Box1[3, 0] = b3;
S_Box1[3, 1] = b1;
S_Box1[3, 2] = b3;
S_Box1[3, 3] = b2;
//---------------------
S_Box2[0, 0] = b0;
S_Box2[0, 1] = b1;
S_Box2[0, 2] = b2;
S_Box2[0, 3] = b3;
S_Box2[1, 0] = b2;
S_Box2[1, 1] = b0;
S_Box2[1, 2] = b1;
S_Box2[1, 3] = b3;
S_Box2[2, 0] = b3;
S_Box2[2, 1] = b0;
S_Box2[2, 2] = b1;
S_Box2[2, 3] = b0;
S_Box2[3, 0] = b2;
S_Box2[3, 1] = b1;
S_Box2[3, 2] = b0;
S_Box2[3, 3] = b3;
//---------------------
}
public byte Encrypt(byte block)
{
BitArray bits_block = byte2bits(block);
BitArray[] keys = Generate_Keys();
return bits2byte(RIP(Fk(Switch(Fk(IP(bits_block), keys[0])), keys[1])));
//ciphertext = IP-1( fK2 ( SW (fK1 (IP (plaintext)))))
}
public byte Decrypt(byte block)
{
BitArray bits_block = byte2bits(block);
BitArray[] keys = Generate_Keys();
return bits2byte(RIP(Fk(Switch(Fk(IP(bits_block), keys[1])), keys[0])));
//IP-1 ( fK1( SW( fK2( IP(ciphertext)))))
}
BitArray byte2bits(byte block)
{
string bits = decimal2binstr(block);
BitArray result = new BitArray(8);
for (int i = 0; i < bits.Length; i++)
{
result[i] = str2bin(bits[i]);
}
return result;
}
byte bits2byte(BitArray block)
{
string result = "";
for (int i = 0; i < block.Length; i++)
{
result += bin2str(block[i]);
}
return binstr2decimal(result);
}
BitArray[] Generate_Keys()
{
BitArray[] keys = new BitArray[2];
BitArray[] temp = Split_Block(P10(Master_key));
keys[0] = P8(Circular_left_shift(temp[0], 1), Circular_left_shift(temp[1], 1));
keys[1] = P8(Circular_left_shift(temp[0], 3), Circular_left_shift(temp[1], 3)); //1 + 2 = 3
return keys;
}
// decimal to binary string
public string decimal2binstr(byte num)
{
string ret = "";
for (int i = 0; i < 8; i++)
{
if (num % 2 == 1)
ret = "1" + ret;
else
ret = "0" + ret;
num >>= 1;
}
return ret;
}
// binary to decimal string
public byte binstr2decimal(string binstr)
{
byte ret = 0;
for (int i = 0; i < binstr.Length; i++)
{
ret <<= 1;
if (binstr[i] == '1')
ret++;
}
return ret;
}
public string bin2str(bool input)
{
if (input)
return "1";
else
return "0";
}
public bool str2bin(char bit)
{
if (bit == '0')
return false;
else if (bit == '1')
return true;
else
throw new Exception("Key should be in binary format [0,1]");
}
//generates permated array P10
BitArray P10(BitArray key)
{
//0 1 2 3 4 5 6 7 8 9
//2 4 1 6 3 9 0 8 7 5
BitArray permutatedArray = new BitArray(10);
permutatedArray[0] = key[2];
permutatedArray[1] = key[4];
permutatedArray[2] = key[1];
permutatedArray[3] = key[6];
permutatedArray[4] = key[3];
permutatedArray[5] = key[9];
permutatedArray[6] = key[0];
permutatedArray[7] = key[8];
permutatedArray[8] = key[7];
permutatedArray[9] = key[5];
return permutatedArray;
}
//generates permuted array P8
BitArray P8(BitArray part1, BitArray part2)
{
//0 1 2 3 4 5 6 7
//5 2 6 3 7 4 9 8
//6 3 7 4 8 5 10 9
BitArray permutatedArray = new BitArray(8);
permutatedArray[0] = part2[0];//5
permutatedArray[1] = part1[2];
permutatedArray[2] = part2[1];//6
permutatedArray[3] = part1[3];
permutatedArray[4] = part2[2];//7
permutatedArray[5] = part1[4];
permutatedArray[6] = part2[4];//9
permutatedArray[7] = part2[3];//8
return permutatedArray;
}
BitArray P4(BitArray part1, BitArray part2)
{
//0 1 2 3
//2 4 3 1
//1 3 2 0
BitArray permutatedArray = new BitArray(4);
permutatedArray[0] = part1[1];
permutatedArray[1] = part2[1];//3
permutatedArray[2] = part2[0];//2
permutatedArray[3] = part1[0];
return permutatedArray;
}
BitArray EP(BitArray input)
{
//0 1 2 3
//4 1 2 3 2 3 4 1
//3 0 1 2 1 2 3 0
BitArray permutatedArray = new BitArray(8);
permutatedArray[0] = input[3];
permutatedArray[1] = input[0];
permutatedArray[2] = input[1];
permutatedArray[3] = input[2];
permutatedArray[4] = input[1];
permutatedArray[5] = input[2];
permutatedArray[6] = input[3];
permutatedArray[7] = input[0];
return permutatedArray;
}
//generates permuted text IP
BitArray IP(BitArray plainText)
{
//0 1 2 3 4 5 6 7
//1 5 2 0 3 7 4 6
BitArray permutatedArray = new BitArray(8);
permutatedArray[0] = plainText[1];
permutatedArray[1] = plainText[5];
permutatedArray[2] = plainText[2];
permutatedArray[3] = plainText[0];
permutatedArray[4] = plainText[3];
permutatedArray[5] = plainText[7];
permutatedArray[6] = plainText[4];
permutatedArray[7] = plainText[6];
return permutatedArray;
}
BitArray RIP(BitArray permutedText)
{
//0 1 2 3 4 5 6 7
//3 0 2 4 6 1 7 5
BitArray permutatedArray = new BitArray(8);
permutatedArray[0] = permutedText[3];
permutatedArray[1] = permutedText[0];
permutatedArray[2] = permutedText[2];
permutatedArray[3] = permutedText[4];
permutatedArray[4] = permutedText[6];
permutatedArray[5] = permutedText[1];
permutatedArray[6] = permutedText[7];
permutatedArray[7] = permutedText[5];
return permutatedArray;
}
BitArray Circular_left_shift(BitArray a, int bitNumber)
{
BitArray shifted = new BitArray(a.Length);
int index = 0;
for (int i = bitNumber; index < a.Length; i++)
{
shifted[index++] = a[i % a.Length];
}
return shifted;
}
BitArray[] Split_Block(BitArray block)
{
BitArray[] splited = new BitArray[2];
splited[0] = new BitArray(block.Length / 2);
splited[1] = new BitArray(block.Length / 2);
int index = 0;
for (int i = 0; i < block.Length / 2; i++)
{
splited[0][i] = block[i];
}
for (int i = block.Length / 2; i < block.Length; i++)
{
splited[1][index++] = block[i];
}
return splited;
}
BitArray S_Boxes(BitArray input, int no)
{
BitArray[,] current_S_Box;
if (no == 1)
current_S_Box = S_Box1;
else
current_S_Box = S_Box2;
return current_S_Box[binstr2decimal(bin2str(input[0]) + bin2str(input[3])),
binstr2decimal(bin2str(input[1]) + bin2str(input[2]))];
}
BitArray F(BitArray right, BitArray sk)
{
BitArray[] temp = Split_Block(Xor(EP(right), sk));
return P4(S_Boxes(temp[0], 1), S_Boxes(temp[1], 2));
}
BitArray Fk(BitArray IP, BitArray key)
{
BitArray[] temp = Split_Block(IP);
BitArray Left = Xor(temp[0], F(temp[1], key));
BitArray joined = new BitArray(8);
int index = 0;
for (int i = 0; i < 4; i++)
{
joined[index++] = Left[i];
}
for (int i = 0; i < 4; i++)
{
joined[index++] = temp[1][i];
}
return joined;
}
BitArray Switch(BitArray input)
{
BitArray switched = new BitArray(8);
int index = 0;
for (int i = 4; index < input.Length; i++)
{
switched[index++] = input[i % input.Length];
}
return switched;
}
BitArray Xor(BitArray a, BitArray b)
{
return b.Xor(a);
}
}
}