clsaes.cs

用CSHARP实现的AES算法源代码

				}
			}
		}  // SubBytes
		private void InvSubBytes()
		{
			for (int r = 0; r < 4; ++r)
			{
				for (int c = 0; c < 4; ++c)
				{
					this.State[r,c] = this.iSbox[ (this.State[r,c] >> 4), (this.State[r,c] & 0x0f) ];
				}
			}
		}  // InvSubBytes
		private void ShiftRows()
		{
			byte[,] temp = new byte[4,4];
			for (int r = 0; r < 4; ++r)  // copy State into temp[]
			{
				for (int c = 0; c < 4; ++c)
				{
					temp[r,c] = this.State[r,c];
				}
			}
			for (int r = 1; r < 4; ++r)  // shift temp into State
			{
				for (int c = 0; c < 4; ++c)
				{
					this.State[r,c] = temp[ r, (c + r) % Nb ];
				}
			}
		}  // ShiftRows()
		private void InvShiftRows()
		{
			byte[,] temp = new byte[4,4];
			for (int r = 0; r < 4; ++r)  // copy State into temp[]
			{
				for (int c = 0; c < 4; ++c)
				{
					temp[r,c] = this.State[r,c];
				}
			}
			for (int r = 1; r < 4; ++r)  // shift temp into State
			{
				for (int c = 0; c < 4; ++c)
				{
					this.State[r, (c + r) % Nb ] = temp[r,c];
				}
			}
		}  // InvShiftRows()
		private void MixColumns()
		{
			byte[,] temp = new byte[4,4];
			for (int r = 0; r < 4; ++r)  // copy State into temp[]
			{
				for (int c = 0; c < 4; ++c)
				{
					temp[r,c] = this.State[r,c];
				}
			}
        
			for (int c = 0; c < 4; ++c)
			{
				this.State[0,c] = (byte) ( (int)gfmultby02(temp[0,c]) ^ (int)gfmultby03(temp[1,c]) ^
					(int)gfmultby01(temp[2,c]) ^ (int)gfmultby01(temp[3,c]) );
				this.State[1,c] = (byte) ( (int)gfmultby01(temp[0,c]) ^ (int)gfmultby02(temp[1,c]) ^
					(int)gfmultby03(temp[2,c]) ^ (int)gfmultby01(temp[3,c]) );
				this.State[2,c] = (byte) ( (int)gfmultby01(temp[0,c]) ^ (int)gfmultby01(temp[1,c]) ^
					(int)gfmultby02(temp[2,c]) ^ (int)gfmultby03(temp[3,c]) );
				this.State[3,c] = (byte) ( (int)gfmultby03(temp[0,c]) ^ (int)gfmultby01(temp[1,c]) ^
					(int)gfmultby01(temp[2,c]) ^ (int)gfmultby02(temp[3,c]) );
			}
		}  // MixColumns
		private void InvMixColumns()
		{
			byte[,] temp = new byte[4,4];
			for (int r = 0; r < 4; ++r)  // copy State into temp[]
			{
				for (int c = 0; c < 4; ++c)
				{
					temp[r,c] = this.State[r,c];
				}
			}
        
			for (int c = 0; c < 4; ++c)
			{
				this.State[0,c] = (byte) ( (int)gfmultby0e(temp[0,c]) ^ (int)gfmultby0b(temp[1,c]) ^
					(int)gfmultby0d(temp[2,c]) ^ (int)gfmultby09(temp[3,c]) );
				this.State[1,c] = (byte) ( (int)gfmultby09(temp[0,c]) ^ (int)gfmultby0e(temp[1,c]) ^
					(int)gfmultby0b(temp[2,c]) ^ (int)gfmultby0d(temp[3,c]) );
				this.State[2,c] = (byte) ( (int)gfmultby0d(temp[0,c]) ^ (int)gfmultby09(temp[1,c]) ^
					(int)gfmultby0e(temp[2,c]) ^ (int)gfmultby0b(temp[3,c]) );
				this.State[3,c] = (byte) ( (int)gfmultby0b(temp[0,c]) ^ (int)gfmultby0d(temp[1,c]) ^
					(int)gfmultby09(temp[2,c]) ^ (int)gfmultby0e(temp[3,c]) );
			}
		}  // InvMixColumns
		private static byte gfmultby01(byte b)
		{
			return b;
		}
		private static byte gfmultby02(byte b)
		{
			if (b < 0x80)
				return (byte)(int)(b <<1);
			else
				return (byte)( (int)(b << 1) ^ (int)(0x1b) );
		}
		private static byte gfmultby03(byte b)
		{
			return (byte) ( (int)gfmultby02(b) ^ (int)b );
		}
		private static byte gfmultby09(byte b)
		{
			return (byte)( (int)gfmultby02(gfmultby02(gfmultby02(b))) ^
				(int)b );
		}
		private static byte gfmultby0b(byte b)
		{
			return (byte)( (int)gfmultby02(gfmultby02(gfmultby02(b))) ^
				(int)gfmultby02(b) ^
				(int)b );
		}
		private static byte gfmultby0d(byte b)
		{
			return (byte)( (int)gfmultby02(gfmultby02(gfmultby02(b))) ^
				(int)gfmultby02(gfmultby02(b)) ^
				(int)(b) );
		}
		private static byte gfmultby0e(byte b)
		{
			return (byte)( (int)gfmultby02(gfmultby02(gfmultby02(b))) ^
				(int)gfmultby02(gfmultby02(b)) ^
				(int)gfmultby02(b) );
		}
		private void KeyExpansion()
		{
			this.w = new byte[Nb * (Nr+1), 4];  // 4 columns of bytes corresponds to a word
    
			for (int row = 0; row < Nk; ++row)
			{
				this.w[row,0] = this.key[4*row];
				this.w[row,1] = this.key[4*row+1];
				this.w[row,2] = this.key[4*row+2];
				this.w[row,3] = this.key[4*row+3];
			}
			byte[] temp = new byte[4];
			for (int row = Nk; row < Nb * (Nr+1); ++row)
			{
				temp[0] = this.w[row-1,0]; temp[1] = this.w[row-1,1];
				temp[2] = this.w[row-1,2]; temp[3] = this.w[row-1,3];
				if (row % Nk == 0)  
				{
					temp = SubWord(RotWord(temp));
          
					temp[0] = (byte)( (int)temp[0] ^ (int)this.Rcon[row/Nk,0] );
					temp[1] = (byte)( (int)temp[1] ^ (int)this.Rcon[row/Nk,1] );
					temp[2] = (byte)( (int)temp[2] ^ (int)this.Rcon[row/Nk,2] );
					temp[3] = (byte)( (int)temp[3] ^ (int)this.Rcon[row/Nk,3] );
				}
				else if ( Nk > 6 && (row % Nk == 4) )  
				{
					temp = SubWord(temp);
				}
        
				// w[row] = w[row-Nk] xor temp
				this.w[row,0] = (byte) ( (int)this.w[row-Nk,0] ^ (int)temp[0] );
				this.w[row,1] = (byte) ( (int)this.w[row-Nk,1] ^ (int)temp[1] );
				this.w[row,2] = (byte) ( (int)this.w[row-Nk,2] ^ (int)temp[2] );
				this.w[row,3] = (byte) ( (int)this.w[row-Nk,3] ^ (int)temp[3] );
       
			}  // for loop
		}  // KeyExpansion()
		private byte[] SubWord(byte[] word)
		{
			byte[] result = new byte[4];
			result[0] = this.Sbox[ word[0] >> 4, word[0] & 0x0f ];
			result[1] = this.Sbox[ word[1] >> 4, word[1] & 0x0f ];
			result[2] = this.Sbox[ word[2] >> 4, word[2] & 0x0f ];
			result[3] = this.Sbox[ word[3] >> 4, word[3] & 0x0f ];
			return result;
		}
		private byte[] RotWord(byte[] word)
		{
			byte[] result = new byte[4];
			result[0] = word[1];
			result[1] = word[2];
			result[2] = word[3];
			result[3] = word[0];
			return result;
		}
		public  void Dump()
		{
			Console.WriteLine("Nb = " + Nb + " Nk = " + Nk + " Nr = " + Nr);
			Console.WriteLine("\nThe key is \n" + DumpKey() );
			Console.WriteLine("\nThe Sbox is \n" + DumpTwoByTwo(Sbox));
			Console.WriteLine("\nThe w array is \n" + DumpTwoByTwo(w));
			Console.WriteLine("\nThe State array is \n" + DumpTwoByTwo(State));
		}
		public string DumpKey()
		{
			string s = "";
			for (int i = 0; i < key.Length; ++i)
				s += key[i].ToString("x2") + " ";
			return s;
		}
		public string DumpTwoByTwo(byte[,] a)
		{
			string s ="";
			for (int r = 0; r < a.GetLength(0); ++r)
			{
				s += "["+r+"]" + " ";
				for (int c = 0; c < a.GetLength(1); ++c)
				{
					s += a[r,c].ToString("x2") + " " ;
				}
				s += "\n";
			}
			return s;
		}
	}  // class Aes
}  // ns AesLib