📄 des.c
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///////////////////////////////////////////////////////////////
// 文 件 名 : des.h
// 文件功能 : DES/3DES加密/解密
// 作 者 : 黄双全
// 创建时间 : 2006年9月2日
// 项目名称 : DES加密算法
// 备 注 :
// 历史记录 :
///////////////////////////////////////////////////////////////
#include "des.h"
// 初始置换
const uint8 Table_IP[64] =
{
58, 50, 42, 34, 26, 18, 10, 2, 60, 52, 44, 36, 28, 20, 12, 4,
62, 54, 46, 38, 30, 22, 14, 6, 64, 56, 48, 40, 32, 24, 16, 8,
57, 49, 41, 33, 25, 17, 9, 1, 59, 51, 43, 35, 27, 19, 11, 3,
61, 53, 45, 37, 29, 21, 13, 5, 63, 55, 47, 39, 31, 23, 15, 7
};
// 末置换
const uint8 Table_InverseIP[64] =
{
40, 8, 48, 16, 56, 24, 64, 32, 39, 7, 47, 15, 55, 23, 63, 31,
38, 6, 46, 14, 54, 22, 62, 30, 37, 5, 45, 13, 53, 21, 61, 29,
36, 4, 44, 12, 52, 20, 60, 28, 35, 3, 43, 11, 51, 19, 59, 27,
34, 2, 42, 10, 50, 18, 58, 26, 33, 1, 41, 9, 49, 17, 57, 25
};
// 扩展置换
const uint8 Table_E[48] =
{
32, 1, 2, 3, 4, 5, 4, 5, 6, 7, 8, 9,
8, 9, 10, 11, 12, 13, 12, 13, 14, 15, 16, 17,
16, 17, 18, 19, 20, 21, 20, 21, 22, 23, 24, 25,
24, 25, 26, 27, 28, 29, 28, 29, 30, 31, 32, 1
};
// 密钥初始置换
const uint8 Table_PC1[56] =
{
57, 49, 41, 33, 25, 17, 9, 1, 58, 50, 42, 34, 26, 18,
10, 2, 59, 51, 43, 35, 27, 19, 11, 3, 60, 52, 44, 36,
63, 55, 47, 39, 31, 23, 15, 7, 62, 54, 46, 38, 30, 22,
14, 6, 61, 53, 45, 37, 29, 21, 13, 5, 28, 20, 12, 4
};
// 左右移运算
const signed char Table_Move[2][16] =
{
//加密左移
{1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1},
//解密右移
{0, -1, -2, -2, -2, -2, -2, -2, -1, -2, -2, -2, -2, -2, -2, -1}
};
// 密钥压缩置换
const uint8 Table_PC2[48] =
{
14, 17, 11, 24, 1, 5, 3, 28, 15, 6, 21, 10,
23, 19, 12, 4, 26, 8, 16, 7, 27, 20, 13, 2,
41, 52, 31, 37, 47, 55, 30, 40, 51, 45, 33, 48,
44, 49, 39, 56, 34, 53, 46, 42, 50, 36, 29, 32
};
// S盒
const uint8 Table_SBOX[8][4][16] =
{
// S1
14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7,
0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8,
4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0,
15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13,
// S2
15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10,
3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5,
0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15,
13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9,
// S3
10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8,
13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1,
13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7,
1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12,
// S4
7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15,
13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9,
10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4,
3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14,
// S5
2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9,
14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6,
4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14,
11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3,
// S6
12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11,
10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8,
9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6,
4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13,
// S7
4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1,
13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6,
1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2,
6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12,
// S8
13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7,
1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2,
7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8,
2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11
};
// P盒置换
const uint8 Table_P[32] =
{
16, 7, 20, 21, 29, 12, 28, 17, 1, 15, 23, 26, 5, 18, 31, 10,
2, 8, 24, 14, 32, 27, 3, 9, 19, 13, 30, 6, 22, 11, 4, 25
};
void SET_BIT(uint8 *p_array, uint8 bit_index, uint8 bit_val)
{
if (1 == (bit_val))
{
p_array[(bit_index) >> 3] |= 0x01 << (7 - ((bit_index) & 0x07));
}
else
{
p_array[(bit_index) >> 3] &= ~(0x01 << (7 - ((bit_index) & 0x07)));
}
}
//对两块大小相同的内存区进行异或
//异或结果保存到第一块内存
//uint8 * p_buf_1 内存区1
//const uint8 * p_buf_2 内存区2
//uint8 bytes 内存区大小(单位：字节)
void Xor(uint8 * p_buf_1, const uint8 * p_buf_2, uint8 bytes)
{
while(bytes > 0)
{
bytes--;
p_buf_1[bytes] ^= p_buf_2[bytes];
}
}
//将缓冲区从第bit_start位到第bit_end进行循环左移
//offset只能是1，2
//本段代码还可以优化。
void move_left(uint8 * p_input, uint8 bit_start, uint8 bit_end, uint8 offset)
{
uint8 b_val = 0;
uint8 b_tmp1 = 0;
uint8 b_tmp2 = 0;
//读取bit_start位
b_tmp1 = GET_BIT(p_input, bit_start);
b_tmp2 = GET_BIT(p_input, bit_start + 1);
//循环左移offset位
for(; bit_start <= (bit_end - offset); bit_start++)
{
b_val = GET_BIT(p_input, bit_start + offset);
SET_BIT(p_input, bit_start, b_val);
}
//将bit_start开始的offset位移到bit_end后头来
if (1 == offset)
{
SET_BIT(p_input, bit_end, b_tmp1);
}
else
{
SET_BIT(p_input, bit_end, b_tmp2);
SET_BIT(p_input, bit_end - 1, b_tmp1);
}
}
//将缓冲区从第bit_start位到第bit_end进行循环右移
//offset只能是1，2
//本段代码在性能上还可以优化。
void move_right(uint8 * p_input, uint8 bit_start, uint8 bit_end, uint8 offset)
{
uint8 b_val = 0;
uint8 b_tmp1 = 0;
uint8 b_tmp2 = 0;
//读取bit_end位
b_tmp1 = GET_BIT(p_input, bit_end);
b_tmp2 = GET_BIT(p_input, bit_end - 1);
//循环左移offset位
for(; bit_end >= (bit_start + offset); bit_end--)
{
b_val = GET_BIT(p_input, bit_end - offset);
SET_BIT(p_input, bit_end, b_val);
}
//将bit_end倒数的offset位移到bit_start来
if (1 == offset)
{
SET_BIT(p_input, bit_start, b_tmp1);
}
else
{
SET_BIT(p_input, bit_start, b_tmp2);
SET_BIT(p_input, bit_start + 1, b_tmp1);
}
}
//缓冲区移位
//offset大于0时左移
//offset小于0时右移
void move_bits(uint8 * p_input, uint8 bit_start, uint8 bit_end, char offset)
{
if(0 < offset) //左移
{
move_left(p_input, bit_start, bit_end, offset);
}
else if(0 > offset) //右移
{
move_right(p_input, bit_start, bit_end, -offset);
}
}
//通用置换函数, bits <= 64
//p_input与p_output不能指向同一个地址，否则置换会出错。
void Permutation(uint8 * p_input, uint8 * p_output, const uint8 * Table, uint8 bits)
{
uint8 b_val = FALSE;
uint8 bit_index = 0;
for(bit_index = 0; bit_index < bits; bit_index++)
{
b_val = GET_BIT(p_input, Table[bit_index] - 1);
SET_BIT(p_output, bit_index, b_val);
}
}
//获取从bit_s为起始的第1, 6 位组成行
uint8 S_GetLine(uint8 * p_data_ext, uint8 bit_s)
{
return (GET_BIT(p_data_ext, bit_s + 0) << 1) + GET_BIT(p_data_ext, bit_s + 5);
}
//获取从bit_s为起始的第2,3,4,5位组成列
uint8 S_GetRow(uint8 * p_data_ext, uint8 bit_s)
{
uint8 row;
//2,3,4,5位组成列
row = GET_BIT(p_data_ext, bit_s + 1);
row <<= 1;
row += GET_BIT(p_data_ext, bit_s + 2);
row <<= 1;
row += GET_BIT(p_data_ext, bit_s + 3);
row <<= 1;
row += GET_BIT(p_data_ext, bit_s + 4);
return row;
}
///////////////////////////////////////////////////////////////
// 函 数 名 : des
// 函数功能 : DES加解密
// 处理过程 : 根据标准的DES加密算法用输入的64位密钥对64位密文进行加/解密
// 并将加/解密结果存储到p_output里
// 时 间 : 2006年9月2日
// 返 回 值 :
// 参数说明 : const char * p_data 输入, 加密时输入明文, 解密时输入密文, 64位(8字节)
// const char * p_key 输入, 密钥, 64位(8字节)
// char * p_output 输出, 加密时输出密文, 解密时输入明文, 64位(8字节)
// uint8 mode DES_ENCRYPT 加密 DES_DECRYPT 解密
///////////////////////////////////////////////////////////////
void des(const char * p_data, const char * p_key, const char * p_output, DES_MODE mode)
{
uint8 loop = 0; //16轮运算的循环计数器
uint8 key_tmp[8]; //密钥运算时存储中间结果
uint8 sub_key[6]; //用于存储子密钥
uint8 * p_left;
uint8 * p_right;
uint8 p_right_ext[8]; //R[i]经过扩展置换生成的48位数据(6字节), 及最终结果的存储
uint8 p_right_s[4]; //经过S_BOX置换后的32位数据(4字节)
uint8 s_loop = 0; //S_BOX置换的循环计数器
//密钥第一次缩小换位, 得到一组56位的密钥数据
Permutation(p_key, key_tmp, Table_PC1, 56);
//明文初始化置换
Permutation(p_data, p_output, Table_IP, 64);
p_left = p_output; //L0
p_right = &p_output[4]; //R0
for(loop = 0; loop < 16; loop++)
{
//把缩进小后的把这56位分为左28位和右28位,
//对左28位和右28位分别循环左/右移, 得到一组新数据
//加解密操作时只在移位时有差异
move_bits(key_tmp, 0, 27, Table_Move[mode][loop]);
move_bits(key_tmp, 28, 55, Table_Move[mode][loop]);
//密钥第二次缩小换位，得到一组子48位的子密钥
Permutation(key_tmp, sub_key, Table_PC2, 48);
//R0扩展置换
Permutation(p_right, p_right_ext, Table_E, 48);
//将R0扩展置换后得到的48位数据(6字节)与子密钥进行异或
Xor(p_right_ext, sub_key, 6);
//S_BOX置换
for(s_loop = 0; s_loop < 4; s_loop++)
{
uint8 s_line = 0;
uint8 s_row = 0;
uint8 s_bit = s_loop * 12;
s_line = S_GetLine(p_right_ext, s_bit);
s_row = S_GetRow(p_right_ext, s_bit);
p_right_s[s_loop] = Table_SBOX[s_loop * 2][s_line][s_row];
s_bit += 6;
s_line = S_GetLine(p_right_ext, s_bit);
s_row = S_GetRow(p_right_ext, s_bit);
p_right_s[s_loop] <<= 4;
p_right_s[s_loop] += Table_SBOX[(s_loop * 2) + 1][s_line][s_row];
}
//P置换
Permutation(p_right_s, p_right_ext, Table_P, 32);
Xor(p_right_ext, p_left, 4);
memcpy(p_left, p_right, 4);
memcpy(p_right, p_right_ext, 4);
}
memcpy(&p_right_ext[4], p_left, 4);
memcpy(p_right_ext, p_right, 4);
//最后再进行一次逆置换, 得到最终加密结果
Permutation(p_right_ext, p_output, Table_InverseIP, 64);
}
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