📄 aes.cs
字号:
using System;
using System.Collections.Generic;
using System.Text;
namespace AES_TEST
{
class Aes // Aes类
{
public enum KeySize { Bits128, Bits192, Bits256 };//密钥长度指定为128，192，256位，适合用枚举类型表示
private int Nb;//以32bits位（字）为单位的明文每一个分组包含的块数，在AES中（明文分组为128bits）恒为4
private int Nk;//以32bits位（字）为单位的密钥每一个分组包含的块数，在AES中为4(128bits)，6(128bits)，8(256bits)
private int Nr;//轮数，为10，12，14，取决于密钥长度
private byte[] key;//原始密钥数组，密钥数组长度为4×Nk
private byte[,] Sbox;//S盒，为16×16字节矩阵
private byte[,] iSbox;//逆S盒，为16×16字节矩阵
private byte[,] w;//扩展密钥表，44个字，每个字32bits，即byte[44,4] w
private byte[,] Rcon;//轮常数表，为byte[Nr,4] Rcon
private byte[,] State;//State数组，为4×4字节矩阵，即byte[4,4] State
//以下为Aes类初始化部分
/********************************************************************************************************************************************/
//Aes构造函数，用于初始化Nb,Nk,Nr,key,Sbox,iSbox
public Aes(KeySize keySize,byte[] keyBytes)
{
SetNbNkNr(keySize);//根据密钥长度keySize设置Nb,Nk,Nr
this.key=new byte[this.Nk*4];//根据Nk设置密钥数组key长度
keyBytes.CopyTo(this.key, 0);//给key数组赋值
BuildSbox();//初始化“Sbox”
BuildInvSbox();//初始化“逆Sbox”
BuildRcon();//初始化轮常数表Rcon
KeyExpansion();//密钥扩展
}
//SetNbNkNr()函数，根据密钥长度初始化Nb，Nk，Nr
private void SetNbNkNr(KeySize keySize)
{
this.Nb = 4;//Nb恒为4，AES明文分组为128bits，以32bits（字）为单位分块的话，块数Nb就是4
if (keySize == KeySize.Bits128)//密钥长度为128bits
{
this.Nk = 4;//32bits×4＝128bits
this.Nr = 10;
}
if (keySize == KeySize.Bits192)//密钥长度为192bits
{
this.Nk = 6;//32bits×6＝192bits
this.Nr = 12;
}
if (keySize == KeySize.Bits256)//密钥长度为256bits
{
this.Nk = 8;//32bits×8＝256bits
this.Nr = 14;
}
}
//BuildSbox()函数，初始化S盒，见课本P106表5.4（a）S盒
private void BuildSbox()
{
this.Sbox = new byte[16, 16]{//给S盒分配空间，为16×16字节矩阵,并赋值
/* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
/*0*/ {0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76},
/*1*/ {0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0},
/*2*/ {0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15},
/*3*/ {0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75},
/*4*/ {0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84},
/*5*/ {0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf},
/*6*/ {0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8},
/*7*/ {0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2},
/*8*/ {0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73},
/*9*/ {0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb},
/*a*/ {0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79},
/*b*/ {0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08},
/*c*/ {0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a},
/*d*/ {0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e},
/*e*/ {0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf},
/*f*/ {0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16} };
}
//BuildInvSbox()函数，初始化逆S盒，见课本P106表5.4（b）逆S盒
private void BuildInvSbox()
{
this.iSbox = new byte[16, 16]{ //给逆S盒分配空间，为16×16字节矩阵,并赋值
/* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
/*0*/ {0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb},
/*1*/ {0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb},
/*2*/ {0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e},
/*3*/ {0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25},
/*4*/ {0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92},
/*5*/ {0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84},
/*6*/ {0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06},
/*7*/ {0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b},
/*8*/ {0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73},
/*9*/ {0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e},
/*a*/ {0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b},
/*b*/ {0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4},
/*c*/ {0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f},
/*d*/ {0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef},
/*e*/ {0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61},
/*f*/ {0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d} };
}
//BuildRcon()函数，初始化轮常数表Rcon，见课本P111上面的轮常数表
private void BuildRcon()
{
this.Rcon = new byte[11, 4] {
{0x00, 0x00, 0x00, 0x00},
{0x01, 0x00, 0x00, 0x00},
{0x02, 0x00, 0x00, 0x00},
{0x04, 0x00, 0x00, 0x00},
{0x08, 0x00, 0x00, 0x00},
{0x10, 0x00, 0x00, 0x00},
{0x20, 0x00, 0x00, 0x00},
{0x40, 0x00, 0x00, 0x00},
{0x80, 0x00, 0x00, 0x00},
{0x1b, 0x00, 0x00, 0x00},
{0x36, 0x00, 0x00, 0x00} };
}
//KeyExpansion()函数，进行密钥扩展，参照课本P110的伪代码
private void KeyExpansion()
{
//首先，输入密钥直接被复制到扩展密钥数组的前Nk(4-128,6-192,8-256)个字。
this.w = new byte[Nb * (Nr + 1), 4]; //（1＋轮数Nr）×128bits的线性数组w
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];
}
//然后，每次用4个字 / 128bits填充扩展密钥数组余下的部分。在扩展密钥数组中，w[i]的值依赖于w[i-1]和w[i-Nk].
byte[] temp = new byte[4];//一个temp对应一个w,因为在C#中没有 word类型，用 4字节数组实现了一个字。
for (int row = Nk; row < Nb * (Nr + 1); ++row)//Nk为密码块数
{
//对应课本P110的temp=w[i-1]
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)
{
//对应课本P110的temp=SubWord(RotWord(temp))XOR Rcon[i/Nk]
temp = SubWord(RotWord(temp));
//两个字节相互的异或操作。它需要一些从 byte 到 int 的强制类型转换并转回到 byte，因为异或操作“^”是不能定义在 C# 的 byte 类型上
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);
}
// 对应课本P110的w[i] = w[i-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]);
}
}
//函数RotWord()：实现字循环功能，使一个字的4个字节循环左移一个字节
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;
}
//函数SubWord()：字节代换利用S盒对输入字中的每个字节进行字节代换
private byte[] SubWord(byte[] word)
{
byte[] result = new byte[4];
result[0] = this.Sbox[word[0] >> 4/*高4位*/, word[0] & 0x0f/*低4位*/];
result[1] = this.Sbox[word[1] >> 4/*高4位*/, word[1] & 0x0f/*低4位*/];
result[2] = this.Sbox[word[2] >> 4/*高4位*/, word[2] & 0x0f/*低4位*/];
result[3] = this.Sbox[word[3] >> 4/*高4位*/, word[3] & 0x0f/*低4位*/];
/*
对于一个给定字节，用 >> 操作符右移 4 位将得到 x 索引，并且与 0000 1111 进行逻辑与得到 y 值。虽然有些长，但比实际代码更可读，可以象下面这样：
int x = word[0] >> 4;
int y = word[0] & 0x0f;
byte substitute = this.Sbox[x,y];
result[0] = substitute;
代替上面用的代码：
*/
return result;
}
/********************************************************************************************************************************************/
//以下为加密过程
/********************************************************************************************************************************************/
//加密函数
public void Cipher(byte[] input, byte[] output)
{
//接收输入，存入State数组
this.State = new byte[4, Nb];//Nb恒为4
for (int i = 0; i < 16; i++)
{
this.State[i % 4, i / 4] = input[i];//State数组竖着存放输入字符串
}
AddRoundKey(0);//初始轮密钥加，第0轮
for (int round = 1; round <= (Nr - 1); round++)//每一轮过程如下
{
SubBytes();//字节代换
ShiftRows();//行移位
MixColumns();//列混淆
AddRoundKey(round);//第round轮
}
//最后一轮，第Nr轮
SubBytes();//字节代换
ShiftRows();//行移位
AddRoundKey(Nr);//第Nr轮
//输出处理
for (int i = 0; i < 16; i++)
⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -