精品專題資料（2022-2023年收藏）杭電密碼學DES密碼實驗介紹

1、課程實驗報告課 程密碼學實驗學 院通信工程學院專 業(yè)信息安全班 級14083611學 號14084125學生姓名劉博實驗名稱DES密碼實驗授課教師胡麗琴DES密碼實驗一、實驗要求：1、了解分組密碼的起源與涵義。2、掌握DES密碼的加解密原理。3、用Visual C+實現(xiàn)DES密碼程序并輸出結果。二、實驗內(nèi)容：1、1949年，Shannon發(fā)表了保密系統(tǒng)的通信理論，奠定了現(xiàn)代密碼學的基礎。他還指出混淆和擴散是設計密碼體制的兩種基本方法。擴散指的是讓明文中的每一位影響密文中的許多位，混淆指的是將密文與密鑰之間的統(tǒng)計關系變得盡可能復雜。而分組密碼的設計基礎正是擴散和混淆。在分組密碼中，明文序列被分成

2、長度為n的元組，每組分別在密鑰的控制下經(jīng)過一系列復雜的變換，生成長度也是n的密文元組，再通過一定的方式連接成密文序列。2、DES是美國聯(lián)邦信息處理標準(FIPS)于1977年公開的分組密碼算法，它的設計基于Feistel對稱網(wǎng)絡以及精心設計的S盒，在提出前已經(jīng)進行了大量的密碼分析，足以保證在當時計算條件下的安全性。不過，隨著計算能力的飛速發(fā)展，現(xiàn)如今DES已經(jīng)能用密鑰窮舉方式破解。雖然現(xiàn)在主流的分組密碼是AES，但DES的設計原理仍有重要參考價值。在本實驗中，為簡便起見，就限定DES密碼的明文、密文、密鑰均為64bit，具體描述如下：明文m是64bit序列。初始密鑰K是64 bit序列(含8個

3、奇偶校驗bit)。子密鑰K1, K2K16均是48 bit序列。輪變換函數(shù)f (A,J)：輸入A(32 bit序列), J(48 bit序列)，輸出32 bit序列。密文c是64 bit序列。1) 子密鑰生成： 輸入初始密鑰，生成16輪子密鑰K1, K2K16。初始密鑰(64bit)經(jīng)過置換PC-1，去掉了8個奇偶校驗位，留下56 bit，接著分成兩個28 bit的分組C0與D0，再分別經(jīng)過一個循環(huán)左移函數(shù)LS1，得到C1與D1，連成56 bit數(shù)據(jù)，然后經(jīng)過置換PC-2，輸出子密鑰K1，以此類推產(chǎn)生K2至K16。注意：置換PC-1、PC-2會在下文中會具體給出； 函數(shù)LSi為向左循環(huán)移動 1

4、個位置(i=1,2,9,16) 2個位置(i=3,4,5,6,7,8,10,11,12,13,14,15)。詳見下圖：初始密鑰(64bit)置換PC-1C1D1D0(28bit)C0(28bit)置換PC-2K1LS1LS1LS2LS2LS16LS16C16D16置換PC-2K162) 輪變換函數(shù)f：f是DES加解密中每一輪的核心運算，輸入A(32 bit), J(48 bit)，輸出32 bit。將A做一個擴展運算E，變成48 bit，記為E(A)。計算B=E(A)J，將B分為8組B1B8，每組Bi為6 bit，通過相應的S盒Si，輸出Ci為4 bit，將所有Ci連成C(32 bit)，再通

5、過置換P，得到最后的輸出f(A,J)，為32 bit。在加密或解密的第i輪，A = Ri-1，J = Ki。注意：每個S盒Si是416的矩陣，輸入b0b1b2b3b4b5 (6 bit)，令L是b0b5對應的十進制數(shù)，n是b1b2b3b4對應的十進制數(shù)，輸出矩陣中第L行n列所對應數(shù)的二進制表示。詳見下圖：4 bit6 bitA (32bit)E(A) (48bit) B1 B2 B3 B4 B5 B6 B7 B8J (48bit)ES1S2S8S7S6S5S4S3 C1 C2 C3 C4 C5 C6 C7 C8Pf(A,J) (32bit)3) 加/解密：DES的加密和解密幾乎一樣，不同之處在

6、于加密時輸入是明文，子密鑰使用順序為K1K2K16；解密時輸入是密文，子密鑰使用順序為K16K15K1。 以加密為例，輸入明文分組64 bit，先進行一次初始置換IP，對置換后的數(shù)據(jù)X0分成左右兩半L0與R0，根據(jù)第一個子密鑰K1對R0實行輪變換f(R0, K1)，將結果與L0作逐位異或運算，得到的結果成為下一輪的R1，R0則成為下一輪的L1。如此循環(huán)16次，最后得到L16與R16?？捎孟铝泄胶啙嵉乇硎荆鹤詈髮?4 bit數(shù)據(jù)R16, L16實行IP的逆置換IP-1，即得密文分組。注意：第16輪變換后并未交換L16與R16，而直接將R16, L16作為IP-1的輸入。詳見下圖： L0輸入初始

7、置換IPR0fK1R1=L0f(R0,K1)L1=R0fKiL15=R14R15=L14f(R14,K15)fR16=L15f(R15,K16)K16L16=R15逆初始置換IP-1輸出3、使用Visual C+編寫程序，實現(xiàn)DES密碼及輸出界面，主要步驟：1) 新建一個空項目，取名des。2) 在左邊的解決方案資源管理器中添加cpp文件，取名為des.cpp。3) 在des.cpp中先寫入 #include using namespace std; static bool SubKey1648; /定義子密鑰，使得所有函數(shù)都能調(diào)用 static const unsigned char IP_

8、Table64 = /定義IP置換表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;static const unsigned char IPInv_Table64 = /定義IP逆置換表40,8,48,16,56,24,64,32,39,7,47,15,55,23,63,31,3

9、8,6,46,14,54,22,62,30,37,5,45,13,53,21,61,29,36,4,44,12,52,20,60,28,35,3,43,11,51,19,59,27,34,2,42,10,50,18,58,26,33,1,41,9,49,17,57,25;static const unsigned char E_Table48 = /定義E擴展表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

10、,30,31,32,1;static const unsigned char P_Table32 = /定義P置換表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;static const unsigned char PC1_Table56 = /定義PC1置換表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

11、,54,46,38,30,22,14,6,61,53,45,37,29,21,13,5,28,20,12,4;static const unsigned char PC2_Table48 = /定義PC2置換表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;static const unsigned char LS_Table16 = /定義左移位數(shù)表1,1,2,2,2,2

12、,2,2,1,2,2,2,2,2,2,1;static unsigned char S_Box8416 = /S盒/S114,4,13,1,2,15,11,8,3,10,6,12,5,9,0,7,0,15,7,4,14,2,13,1,10,6,12,11,9,5,3,8,4,1,14,8,13,6,2,11,15,12,9,7,3,10,5,0,15,12,8,2,4,9,1,7,5,11,3,14,10,0,6,13,/S215,1,8,14,6,11,3,4,9,7,2,13,12,0,5,10,3,13,4,7,15,2,8,14,12,0,1,10,6,9,11,5,0,14,7,11

13、,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,/S310,0,9,14,6,3,15,5,1,13,12,7,11,4,2,8,13,7,0,9,3,4,6,10,2,8,5,14,12,11,15,1,13,6,4,9,8,15,3,0,11,1,2,12,5,10,14,7,1,10,13,0,6,9,8,7,4,15,14,3,11,5,2,12,/S47,13,14,3,0,6,9,10,1,2,8,5,11,12,4,15,13,8,11,5,6,15,0,3,4,7,2,12,1,10,14,9

14、,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,/S52,12,4,1,7,10,11,6,8,5,3,15,13,0,14,9,14,11,2,12,4,7,13,1,5,0,15,10,3,9,8,6,4,2,1,11,10,13,7,8,15,9,12,5,6,3,0,14,11,8,12,7,1,14,2,13,6,15,0,9,10,4,5,3,/S612,1,10,15,9,2,6,8,0,13,3,4,14,7,5,11,10,15,4,2,7,12,9,5,6,1,13,1

15、4,0,11,3,8,9,14,15,5,2,8,12,3,7,0,4,10,1,13,11,6,4,3,2,12,9,5,15,10,11,14,1,7,6,0,8,13,/S74,11,2,14,15,0,8,13,3,12,9,7,5,10,6,1,13,0,11,7,4,9,1,10,14,3,5,12,2,15,8,6,1,4,11,13,12,3,7,14,10,15,6,8,0,5,9,2,6,11,13,8,1,4,10,7,9,5,0,15,14,2,3,12,/S813,2,8,4,6,15,11,1,10,9,3,14,5,0,12,7,1,15,13,8,10,3,7,

16、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;4) 編寫各個模塊函數(shù)，例如：void ByteToBit(bool* Out, const unsigned char* In, int bits); /將字符數(shù)組In轉(zhuǎn)化為bool數(shù)組Out，bits控制轉(zhuǎn)換bit數(shù)void HalfByteToBit(bool* Out, const unsigned char* In, int bits); /將半字符數(shù)組In(4 bit)轉(zhuǎn)化為bool數(shù)組Ou

17、tvoid BitToByte(unsigned char* Out, const bool* In, int bits);/將bool數(shù)組In轉(zhuǎn)化為字符數(shù)組Outvoid Transform(bool* Out, bool* In, const unsigned char* Table, int len);/利用置換表Table將bool數(shù)組In轉(zhuǎn)換成長度為len的bool數(shù)組Outvoid RotateL(bool* In, int len, int loop);/對長度為len的bool數(shù)組In循環(huán)左移loop位void Des_SetSubKey(unsigned char Key8)

18、;/利用初始密鑰Key生成16輪子密鑰SubKey， 注意前文已定義static bool SubKey1648; void Xor(bool* InA, bool* InB, int len);/將bool數(shù)組InB與InA逐位做異或，結果存入InAvoid S_Func(bool Out32, bool In48);/利用S盒S_Box將bool數(shù)組In轉(zhuǎn)換為bool數(shù)組Outvoid F_Func(bool In32, bool Ki48);/利用子密鑰Ki對bool數(shù)組In做輪變換函數(shù)，結果仍存入Invoid Des_Run(unsigned char Out8, unsigned c

19、har In8, bool flag);/Des加解密：輸入字符數(shù)組In，輸出字符數(shù)組Out， flag=1時代表加密，flag=0時代表解密。5) 編寫主函數(shù)，主要步驟有 輸入明文字符序列(8個字符)； 輸入密鑰字符序列(8個字符)； 生成16輪子密鑰； 加密并輸出密文； 解密并輸出解密后的明文。提示點：1) 輸入輸出盡量使用cin、cout這兩個函數(shù)，編寫函數(shù)時多輸出中間變量查看結果。2) 函數(shù)memcpy(void *dest, const void *src, size_t n) 用于將源地址src處n 個單位數(shù)據(jù)拷貝至目的地址dest處, 適用于bool數(shù)組的拷貝。3) 部分函數(shù)參考

20、代碼 void Transform(bool* Out, bool* In, const unsigned char* Table, int len)bool Temp256; /臨時數(shù)組長度定義成足夠大的即可for(int i=0;ilen;i+)Tempi = InTablei-1;memcpy(Out, Temp, len);void ByteToBit(bool* Out, const unsigned char* In, int bits)for (int i=0;i(7-i%8) & 1; void HalfByteToBit(bool* Out, const unsigned c

21、har* In, int bits)for (int i=0;i(3-i%4) & 1; void BitToByte(unsigned char* Out, const bool* In, int bits)for(int i=0;ibits;i+)Outi/8 = (Ini(7-i%8) + Outi/8; DES密碼程序代碼如下：(置換表, S盒等已有的代碼不用寫)#include stdafx.h#include 13113424_yf.h#include 13113424_yfDlg.h#include #include #ifdef _DEBUG#define new DEBUG_

22、NEW#undef THIS_FILEstatic char THIS_FILE = _FILE_;#endifconst char IP_Table64= 58,50,42,34,26,18,10, 2,60,52,44,36,28,20,12, 4, /置換IP62,54,46,38,30,22,14, 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 ;const char IPR_Table64

23、= 40, 8,48,16,56,24,64,32,39, 7,47,15,55,23,63,31, /逆置換IP38, 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;static char E_Table48= /擴展E變換32, 1, 2, 3, 4, 5, 4, 5, 6, 7, 8, 9, 8, 9,10,11,12,13,12,13,14,15,16,1

24、7, 16,17,18,19,20,21,20,21,22,23,24,25, 24,25,26,27,28,29,28,29,30,31,32, 1;static char PC1_Table56=57,49,41,33,25,17, 9, 1,58,50,42,34,26,18, /揀選變換PC-110, 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;static char Move_Table

25、16= /變換左移LS 1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1; static char PC2_Table48=14,17,11,24, 1, 5, 3,28,15, 6,21,10, /揀選變換PC-223,19,12, 4,26, 8,16, 7,27,20,13, 2,41,52,31,37,47,55,30,40,51,34,33,48,44,49,39,56,34,53,46,42,50,36,29,32; static char S_Box8416= /8個S-盒置換表14, 4,13, 1, 2,15,11, 8, 3,10

26、, 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, 6,13,15, 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

27、, 2,15,13, 8,10, 1, 3,15, 4, 2,11, 6, 7,12, 0, 5,14, 9,10, 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, 7,13,14, 3, 0, 6, 9,10, 1, 2, 8, 5,11,12, 4,15,13, 8

28、,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, 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

29、, 2,13, 6,15, 0, 9,10, 4, 5, 3,12, 1,10,15, 9, 2, 6, 8, 0,13, 3, 4,14, 7, 5,11,10,15, 4, 2, 7,12, 0, 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, 4,11, 2,14,15, 0, 8,13, 3,12, 9, 7, 5,10, 6, 1,13, 0,11, 7, 4, 0, 1,10,14, 3

30、, 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, 3,12,13, 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

31、, 6,11;static char P_Table32= /P-盒矩陣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;static bool SubKey1648=0;void BitsCopy(bool *DatOut,bool *DatIn,int Len) int i=0;for(i=0;iLen;i+)DatOuti=DatIni;void ByteToBit(bool *DatOut,char *DatIn,int Num) int i=0

32、;for(i=0;i(i%8)&0x01; void BitToByte(char *DatOut,bool *DatIn,int Num) int i=0;for(i=0;i(Num/8);i+)DatOuti=0; for(i=0;iNum;i+)DatOuti/8|=DatIni(i%8);/初始置換IPvoid TablePermute(bool *DatOut,bool *DatIn,const char *Table,int Num) int i=0;static bool Temp256=0;for(i=0;iNum;i+) / Num為置換的長度 Tempi=DatInTabl

33、ei-1; / 原來的數(shù)據(jù)按對應的表上的位置排列 BitsCopy(DatOut,Temp,Num); / 把緩存Temp的值輸出 / 子密鑰的移位void LoopMove(bool *DatIn,int Len,int Num) / 循環(huán)左移 Len數(shù)據(jù)長度 Num移動位數(shù)static bool Temp256=0; / 緩存 OKBitsCopy(Temp,DatIn,Num); / 將數(shù)據(jù)最左邊的Num位(被移出去的)存入Temp BitsCopy(DatIn,DatIn+Num,Len-Num); / 將數(shù)據(jù)左邊開始的第Num移入原來的空間BitsCopy(DatIn+Len-Num

34、,Temp,Num); / 將緩存中移出去的數(shù)據(jù)加到最右邊 / 按位異或void Xor(bool *DatA,bool *DatB,int Num) / 異或函數(shù)int i=0;for(i=0;iNum;i+)DatAi=DatAiDatBi; / 異或 / 輸入48位 輸出32位 與Ri異或void S_Change(bool DatOut32,bool DatIn48) / S盒變換int i,X,Y; / i為8個S盒 for(i=0,Y=0,X=0;i8;i+,DatIn+=6,DatOut+=4) / 每執(zhí)行一次,輸入數(shù)據(jù)偏移6位 / 每執(zhí)行一次,輸出數(shù)據(jù)偏移4位Y=(DatIn0

35、1)+DatIn5; / af代表第幾行X=(DatIn13)+(DatIn22)+(DatIn31)+DatIn4; / bcde代表第幾列ByteToBit(DatOut,&S_BoxiYX,4); / 把找到的點數(shù)據(jù)換為二進制/ F函數(shù)void F_Change(bool DatIn32,bool DatKi48) / F函數(shù)static bool MiR48=0; / 輸入32位通過E選位變?yōu)?8位TablePermute(MiR,DatIn,E_Table,48); Xor(MiR,DatKi,48); / 和子密鑰異或S_Change(DatIn,MiR); / S盒變換Table

36、Permute(DatIn,DatIn,P_Table,32); / P置換后輸出void SetKey(char KeyIn8) / 獲取子密鑰Ki int i=0;static bool KeyBit64=0; / 密鑰二進制存儲空間 static bool *KiL=&KeyBit0,*KiR=&KeyBit28; / 前28,后28共56ByteToBit(KeyBit,KeyIn,64); / 把密鑰轉(zhuǎn)為二進制存入KeyBit TablePermute(KeyBit,KeyBit,PC1_Table,56); / PC1表置換for(i=0;i16;i+) LoopMove(KiL,28,Move_Tablei); / 左移 LoopMove(KiR,28,Move_Tablei); TablePermute(SubKeyi,KeyBit,PC2_Table,48); / 二維數(shù)組 SubKeyi為每一行起始地址 / 每移一次位進行PC2置換得 Ki 48位