DES加密算法实验报告

1、苏 州 科 技 学 院实 验 报 告学生姓名：杨刘涛 学 号：1220126117 指导教师：陶滔 刘学书 1220126114实验地点：计算机学院大楼东309 实验时间：2015-04-20一、 实验室名称：软件实验室 二、实验项目名称：des加解密算法实现三、实验学时：4学时四、实验原理：des算法由加密、子密钥和解密的生成三部分组成。现将des算法介绍如下。1加密des算法处理的数据对象是一组64比特的明文串。设该明文串为m=m1m2m64 (mi=0或1)。明文串经过64比特的密钥k来加密，最后生成长度为64比特的密文e。其加密过程图示如下：图2-1：des算法加密过程对des算法加密

2、过程图示的说明如下：待加密的64比特明文串m，经过ip置换（初始置换）后，得到的比特串的下标列表如下：表2-1：得到的比特串的下标列表ip58504234261810260524436282012462544638302214664564840322416857494133251791595143352719113615345372921135635547393123157该比特串被分为32位的l0和32位的r0两部分。r0子密钥k1(子密钥的生成将在后面讲)经过变换f(r0,k1)（f变换将在下面讲）输出32位的比特串f1,f1与l0做不进位的二进制加法运算。运算规则为： f1与l0做不进位

3、的二进制加法运算后的结果赋给r1，r0则原封不动的赋给l1。l1与r0又做与以上完全相同的运算，生成l2，r2 一共经过16次运算。最后生成r16和l16。其中r16为l15与f(r15,k16)做不进位二进制加法运算的结果，l16是r15的直接赋值。r16与l16合并成64位的比特串。值得注意的是r16一定要排在l16前面。r16与l16合并后成的比特串，经过置换ip-1（终结置换）后所得比特串的下标列表如下：表2-2：置换后所得比特串的下标列表ip-14084816562464323974715552363313864614542262303754513532161293644412522

4、0602835343115119592734242105018582633141949175725经过置换ip-1后生成的比特串就是密文e。变换f(ri-1,ki):它的功能是将32比特的输入再转化为32比特的输出。其过程如图2-2所示：图2-2：将32比特的输入再转化为32比特的输出 f变换说明：输入ri-1(32比特)经过变换e（扩展置换e）后，膨胀为48比特。膨胀后的比特串的下标列表如下：表2-3：膨胀后的比特串的下标列表e:3212345456789891011121312131415161716171819202120212223242524252627282928293031321

5、膨胀后的比特串分为8组，每组6比特。各组经过各自的s盒后，又变为4比特(具体过程见后)，合并后又成为32比特。该32比特经过p变换（压缩置换p）后，其下标列表如下：表2-4：压缩置换p后的下标列表p:1672021291228171152326518311028241432273919133062211425经过p变换后输出的比特串才是32比特的f（ri-1,ki）.s盒的变换过程: 任取一s盒。见图2-3：图2-3在其输入b1,b2,b3,b4,b5,b6中，计算出x=b1*2+b6, y=b5+b4*2+b3*4+b2*8，再从si表中查出x 行，y 列的值sxy。将sxy化为二进制，即得

6、si盒的输出。（s表如图2-4所示）图2-4以上是des算法加密原理五、实验目的：了解des加密算法及原理，掌握其基本应用。六、实验内容：了解des加密算法及原理，掌握其基本应用，利用java编程实现。七、实验器材（设备、元器件）：（1） pc（2） windows 8.1系统平台（3） java程序开发环境。八、源代码：package windowsdemo;public class desutil byte bytekey; public desutil(string strkey) this.bytekey = strkey.getbytes(); / 声明常量字节数组 private

7、static final int ip = 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 ; / 64 private static final int

8、ip_1 = 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 ; / 64 private static final int pc_1 = 57, 49,

9、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 ; / 56 private static final int pc_2 = 14, 17, 11, 24, 1, 5, 3, 28, 15, 6, 21, 10, 23, 19, 12

10、, 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 ; / 48 private static final int e = 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,

11、25, 26, 27, 28, 29, 28, 29, 30, 31, 32, 1 ; / 48 private static final int p = 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 ; / 32 private static final int s_box = /s-盒 / s_box1 14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0,

12、 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 , / s_box2 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, 1

13、1, 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 , / s_box3 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

14、, 15, 14, 3, 11, 5, 2, 12 , / s_box4 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 , / s_box5 2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3

15、, 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 , / s_box6 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,

16、 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 , / s_box7 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,

17、8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12 , / s_box8 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 ; private static final int le

18、ftmove = 1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2,2, 2, 2, 1 ; / 左移位置列表 private byte unitdes(byte des_key, byte des_data, int flag) / 检测输入参数格式是否正确，错误直接返回空值（null） if (des_key.length != 8) | (des_data.length != 8)| (flag != 1) & (flag != 0) throw new runtimeexception(data format error !); int flags = flag;/

19、 二进制加密密钥 int keydata = new int64;/ 二进制加密数据 int encryptdata = new int64; / 加密操作完成后的字节数组 byte encryptcode = new byte8;/ 密钥初试化成二维数组 int keyarray = new int1648;/ 将密钥字节数组转换成二进制字节数组 keydata = readdatatobirnaryintarray(des_key);/ 将加密数据字节数组转换成二进制字节数组 encryptdata = readdatatobirnaryintarray(des_data);/ 初试化密钥

20、为二维密钥数组 keyinitialize(keydata, keyarray); / 执行加密解密操作 encryptcode = encrypt(encryptdata, flags, keyarray); return encryptcode; / 初试化密钥数组 private void keyinitialize(int key, int keyarray) int i; int j; int k0 = new int56;/ 特别注意：xxxipi-1等类似变换 for (i = 0; i 56; i+) k0i = keypc_1i - 1; / 密钥进行pc-1变换 for (

21、i = 0; i 16; i+) leftbitmove(k0, leftmovei); / 特别注意：xxxipi-1等类似变换 for (j = 0; j 48; j+) keyarrayij = k0pc_2j - 1; / 生成子密钥keyarrayij / 执行加密解密操作 private byte encrypt(int timedata, int flag, int keyarray) int i; byte encrypt = new byte8; int flags = flag; int m = new int64; int mip_1 = new int64;/ 特别注意

22、：xxxipi-1等类似变换 for (i = 0; i 64; i+) mi = timedataipi - 1; / 明文ip变换 if (flags = 1) / 加密 for (i = 0; i -1; i-) loopf(m, i, flags, keyarray); for (i = 0; i 64; i+) mip_1i = mip_1i - 1; / 进行ip-1运算 getencryptresultofbytearray(mip_1, encrypt);/ 返回加密数据 return encrypt; private int readdatatobirnaryintarray

23、(byte intdata) int i; int j; / 将数据转换为二进制数，存储到数组 int intda = new int8; for (i = 0; i 8; i+) intdai = intdatai; if (intdai 0) intdai += 256; intdai %= 256; int intva = new int64; for (i = 0; i 8; i+) for (j = 0; j 8; j+) intva(i * 8) + 7) - j = intdai % 2; intdai = intdai / 2; return intva; private vo

24、id leftbitmove(int k, int offset) int i; / 循环移位操作函数 int c0 = new int28; int d0 = new int28; int c1 = new int28; int d1 = new int28; for (i = 0; i 28; i+) c0i = ki; d0i = ki + 28; if (offset = 1) for (i = 0; i 27; i+) / 循环左移一位 c1i = c0i + 1; d1i = d0i + 1; c127 = c00; d127 = d00; else if (offset = 2)

25、 for (i = 0; i 26; i+) / 循环左移两位 c1i = c0i + 2; d1i = d0i + 2; c126 = c00; d126 = d00; c127 = c01; d127 = d01; for (i = 0; i 28; i+) ki = c1i; ki + 28 = d1i; private void loopf(int m, int times, int flag, int keyarray) int i; int j; int l0 = new int32; int r0 = new int32; int l1 = new int32; int r1 =

26、 new int32; int re = new int48; int s = new int86; int sboxdata = new int8; int svalue = new int32; int rp = new int32; for (i = 0; i 32; i+) l0i = mi; / 明文左侧的初始化 r0i = mi + 32; / 明文右侧的初始化 for (i = 0; i 48; i+) rei = r0ei - 1; / 经过e变换扩充，由32位变为48位 rei = rei + keyarraytimesi; / 与keyarraytimesi按位作不进位加法

27、运算 if (rei = 2) rei = 0; for (i = 0; i 8; i+) / 48位分成8组 for (j = 0; j 6; j+) sij = re(i * 6) + j; / 下面经过s盒，得到8个数 sboxdatai = s_boxi(si0 1) + si5(si1 3) + (si2 2) + (si3 1) + si4; / 8个数变换输出二进制 for (j = 0; j 4; j+) svalue(i * 4) + 3) - j = sboxdatai % 2; sboxdatai = sboxdatai / 2; for (i = 0; i 32; i+

28、) rpi = svaluepi - 1; / 经过p变换 l1i = r0i; / 右边移到左边 r1i = l0i + rpi; if (r1i = 2) r1i = 0; / 重新合成m，返回数组m / 最后一次变换时，左右不进行互换。此处采用两次变换实现不变 if (flag = 0) & (times = 0) | (flag = 1) & (times = 15) mi = r1i; mi + 32 = l1i; else mi = l1i; mi + 32 = r1i; private void getencryptresultofbytearray(int data, byte

29、 value) int i; int j; / 将存储64位二进制数据的数组中的数据转换为八个整数（byte） for (i = 0; i 8; i+) for (j = 0; j 8; j+) valuei += (data(i 3) + j (7 - j); for (i = 0; i 128) valuei -= 255; private byte bytedataformat(byte data, int flag) int len = data.length; int padlen = 8 - (len % 8); int newlen = len + padlen; byte ne

30、wdata = new bytenewlen; system.arraycopy(data, 0, newdata, 0, len); for (int i = len; i newlen; i+) newdatai = (byte) padlen; return newdata; public byte desencrypt(byte des_data, int flag) byte format_key = bytedataformat(bytekey, flag); byte format_data = bytedataformat(des_data, flag); int datalen = format_data.length; int unitcount = datalen / 8; byte result_data = new bytedatalen; for (int i = 0; i = 1) & (delete_len =