1. 加密过程

  1. 首先将明文转换为64位的二进制数据串, 通过初始置换表$IP$​置换得到$S_{1}$​

  2. 将$S_{1}$分为左$L_{1}$​(32bit),右$R_1$​(32bit)两块

  3. 生成子密钥$K_1$~$K_{16}(i=1…16)$​

    3.1. 将密钥转换为64位的二进制数据串, 通过压缩选择置换表$PC_{1}$​置换后得到56位数据串

    把密钥的奇偶校验位(即每个字节的第8位)忽略不参与计算 => 56位的压缩选择置换表$PC_{1}$

    3.2. 将这数据串分成两块$C_{i}$(28bit)和$D_{i}$​(28bit)

    3.3. 循环16轮生成子密钥

    ​ 3.3.1. 通过轮循环左移位数表$R$​将$C_{i}$和$D_{i}$​进行循环左移变化, 变换后生成$C_{i+1}$​和$D_{i+1}$​, 并将$C_{i+1}$​和$D_{i+1}$​合并

    ​ 3.3.2. 通过压缩选择置换表$PC_{2}$​生成子密钥$K_{i}$​(48bit)

  4. 进行16轮迭代运算$F(x)(i=1…16)$​

    4.1. $L_{i+1}=R_{i}$​

    4.2. 将$R_i$通过**扩展置换表$E$**膨胀, 把扩展后的$R_i$​与子密钥$K_{i+1}$​进行异或, 得到48位的数据串. 把该数据串分为8组, 每组6位, 设每组的二进制串为$b_1 b_2 b_3 b_4 b_5 b_6$​. 其中, 将$b_1 b_6$​转换为十进制, 表示$S$​盒中的行坐标$x$​; 将$b_2 b_3 b_4 b_5$转换为十进制, 表示$S$​盒中的列坐标$y$​

    4.3. 根据$S$盒中的行坐标$x$和S盒中的列坐标$y$​, 通过8个不同的$S$盒进行置换压缩运算(参照S-盒置换表$S$), 每个S盒有6位输入,4位输出(不足4位前面补0), 把48位数据压缩为32位数据$S_{2}$​

    4.4. 将$S_{2}$​通过**P-盒置换表$P$**置换得到$S_3$​, 再将$S_3$​与最初64位分组的左半部分异或得到$R_{i+1}$​

  5. 合并上一步骤中迭代完的$L_{16}$​和$R_{16}$​(即$R_{16}L_{16}$​)

  6. 通过逆初始置换表$IP_{R}$​进行置换得到最终的密文输出块

2. 加解密相关表(按使用到的顺序排列)

  • 初始置换表$IP$​(64bit)
1
2
3
4
5
6
7
8
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
  • 压缩选择置换表$PC_{1}$(56bit)
1
2
3
4
5
6
7
8
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
  • 轮循环左移位数表$R$(16bit)
1
2
1, 1, 2, 2, 2, 2, 2, 2,
1, 2, 2, 2, 2, 2, 2, 1
  • 压缩选择置换表$PC_{2}$​(48bit)
1
2
3
4
5
6
7
8
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
  • 扩展置换表$E$(48bit)
1
2
3
4
5
6
7
8
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
  • S-盒置换表$S$​((4x16x8)bit)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
//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-盒置换表$P$​(32bit)
1
2
3
4
5
6
7
8
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
  • 逆初始置换表$IP_{R}$​(64bit)
1
2
3
4
5
6
7
8
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

3. 源码

已上传到我的Github库LengSword/MyCoursesCodes

或直接访问Java/com/lengsword/java/security/crypto进行预览

4. 参考资料

(未完待续)

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