www.pudn.com > des数据加密算法原理与实现..zip > Des.c
/********************************************************************/ /*DES加密程序 1998.3.11 */ /*使用方法: */ /* 加密: DES FILENAME*/ /* TYPE PASSWORD FOR FILENAME XXXXXXXX 8字节 */ /* 解密: DES FILENAME */ /* TYPE PASSWORD FOR FILENAME XXXXXXXX 8字节 */ /*在vc++1.5或tc2.0 DOS6.22下调试通过 */ /********************************************************************/ /*置换算法: 为完成char inblock[8]按换位表charip[64]变换到char outblock[8],先生 成一个变换矩阵 char perm[i][j][k],i=16,j=16,k=8 i:把输入的64bit分成四位一组,每次处理四位信息 j:四位可表示0......15,共16个值 k:对应j的每一个值,给出一个8字节的矩阵表示对应的位的值为1 比如: char inblock{11111110b, 01011101b, 01011010b, 00010100b, 10101011b, 11111000b, 00000100b, 10000101b} 则: char *perm[0][15]={00000001b, 00000001b, 00000000b, 00000000b, 00000001b, 00000001b, 00000000b, 00000000b} char *perm[1][14]={00000000b, 00000000b, 00000001b, 00000000b, 00000000b, 00000000b, 00000001b, 00000001b} char *perm[15][15]={00000000b, 00000000b, 10000000b, 10000000b, 00000000b, 00000000b, 10000000b, 10000000b} char *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 }; */ /*#define DEBUG */ #include char iperm[16][16][8],fperm[16][16][8]; char s[4][4096]; char p32[4][256][4]; char kn[16][6]; /* 密钥*/ endes(inblock,outblock) /* 加密一个64-bit块*/ char *inblock, *outblock; { char iters[17][8]; char swap[8]; /* 放置左右交换的值*/ register int i; register char *s, *t; permute(inblock,iperm,iters[0]); for (i=0; i<16; i++) /* 完成1~16层的交换*/ iter(i,iters[i],iters[i+1]); /* iters[0][0]~iters[0][8]操作后放到iters[1][0]~iters[1][8] iters[1][0]~iters[1][8]操作后放到iters[2][0]~iters[2][8]...以此类推*/ s = swap; t = &iters[16][4]; *s++ = *t++; *s++ = *t++; *s++ = *t++; *s++ = *t++; t = &iters[16][0]; *s++ = *t++; *s++ = *t++; *s++ = *t++; *s++ = *t++; permute(swap,fperm,outblock); } dedes(inblock,outblock) /* 解密一个64-bit 块*/ char *inblock,*outblock; { char iters[17][8]; char swap[8]; register int i; register char *s, *t; permute(inblock,iperm,iters[0]); for (i=0; i<16; i++) iter(15-i,iters[i],iters[i+1]); s = swap; t = &iters[16][4]; *s++ = *t++; *s++ = *t++; *s++ = *t++; *s++ = *t++; t = &iters[16][0]; *s++ = *t++; *s++ = *t++; *s++ = *t++; *s++ = *t++; permute(swap,fperm,outblock); } permute(inblock,perm,outblock) /* 初始换位/最后换位变换*/ char *inblock, *outblock; char perm[16][16][8]; { register int i,j; register char *ib, *ob; register char *p, *q; for (i=0, ob = outblock; i<8; i++) *ob++ = 0; ib = inblock; for (j = 0; j < 16; j += 2, ib++) { ob = outblock; p = perm[j][(*ib >> 4) & 017]; /*高四位*/ q = perm[j + 1][*ib & 017]; /*低四位*/ for (i = 0; i < 8; i++) *ob++ |= *p++ | *q++; /*-----------------*(ob++)=(*ob)|(*(p++)|*(q++))-----------------*/ } } char ip[] /* 初始换位表*/ = { 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 }; char fp[] /* 最后换位表*/ = { 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 }; char pc1[] /* pc1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, 54, 46, 38, 30, 22, 14, 6, 61, 53, 45, 37, 29, 21, 13, 5, 28, 20, 12, 4 }; char totrot[] /* 密钥生成中的循环左移位的累计次数*/ = { 1,2,4,6,8,10,12,14,15,17,19,21,23,25,27,28 }; char pc1m[56]; char pcr[56]; char pc2[] /* pc2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 }; char si[8][64] /* 48->32 bit 压缩表*/ = { /* S[1] */ 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, /* S[2] */ 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, /* S[3] */ 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, /* S[4] */ 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[5] */ 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, /* S[6] */ 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, /* S[7] */ 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, /* S[8] */ 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 }; char p32i[] /* 32-bit 单纯换位表*/ = { 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 }; desinit(key) /* 初始化各种变换矩阵*/ char *key; { #ifdef DEBUG /*deb*/ printf("Initial perm init.\n"); #endif perminit(iperm,ip); #ifdef DEBUG /*deb*/ printf("Final perm init.\n"); #endif perminit(fperm,fp); #ifdef DEBUG /*deb*/ printf("Key sched init.\n"); #endif kinit(key); #ifdef DEBUG /*deb*/ printf("Compression init.\n"); #endif sinit(); #ifdef DEBUG /*deb*/ printf("32-bit perm init.\n"); #endif p32init(); #ifdef DEBUG /*deb*/ printf("End init.\n"); #endif } int bytebit[] = { 0200,0100,040,020,010,04,02,01 }; int nibblebit[] = { 010,04,02,01 }; sinit() /* 初始化s1-s8矩阵*/ { register int i,j; for (i=0; i<4; i++) /* 48位按四个12位(一个半字节)来输入*/ for (j=0; j<4096; j++) s[i][j]=(getcomp(i*2,j>>6)<<4) | (017&getcomp(i*2+1,j&077)); /*每个s项为一个字节,存有两个体代数*/ } getcomp(k,v) /* 用s[k]盒对v进行6bit~4bit的数据压缩*/ int k,v; { register int i,j; i=((v&040)>>4)|(v&1); /*i为每个s盒的行号改行号由v的第一位和最后一位组成*/ j=(v&037)>>1; /* j位s盒的列号,该列号由v的中间四位组成*/ return (int) si[k][(i<<4)+j]; /* 返回对v压缩后的值*/ } kinit(key) /* 初始化密钥的变换矩阵的中间过渡矩阵*/ char *key; /* 64 bits */ { register int i,j,l; int m; for (j=0; j<56; j++) { l=pc1[j]-1; m = l & 07; pc1m[j]=(key[l>>3] & bytebit[m]) ? 1 : 0; /*key[l>>3]确定第1位在char key[8]中的哪一个字节中, char pc1m[56]是完成pc-1型换位的变换矩阵*/ } for (i=0; i<16; i++) /* 共生成16个密钥*/ for (j=0; j<6; j++) /* 密钥kn的每一个字节*/ kn[i][j]=0; for (i=0; i<16; i++) { for (j=0; j<56; j++) pcr[j] = pc1m[(l=j+totrot[i])<(j<28? 28 : 56) ? l: l-28]; /* pcr[j]是每次进行循环左移位后的pc1m[]矩阵*/ for (j=0; j<48; j++) if (pcr[pc2[j]-1]) { l= j & 07; kn[i][j>>3] |= bytebit[l];/*共16个密钥i~[0,16],每个密钥6字节j>>3~[0,5]*/ } } } p32init() /* 初始化32bit换位表的中间过渡矩阵*/ { register int l, j, k; int i,m; for (i=0; i<4; i++) /* 以字节为单位输入,i为字节在输入矩阵中的位置*/ for (j=0; j<256; j++) /* j为所输入字节的可能值[0~256]*/ for (k=0; k<4; k++) p32[i][j][k]=0; for (i=0; i<4; i++) for (j=0; j<256; j++) for (k=0; k<32; k++) { l=p32i[k]-1; if ((l>>3)!=i) continue; if (!(j&bytebit[l&07])) continue; m = k & 07; p32[i][j][k>>3] |= bytebit[m]; } } perminit(perm,p) /* 初始化换位表*/ char perm[16][16][8]; /* 64-bit, 完成换位的中间的过渡矩阵*/ char p[64]; { register int l, j, k; int i,m; for (i=0; i<16; i++) /* 每一个输入的4 bit*/ for (j=0; j<16; j++) /* 每一个4 bit的可能值~[0,16]*/ for (k=0; k<8; k++) /* 每一个屏蔽字*/ perm[i][j][k]=0; /* 过渡矩阵清零*/ for (i=0; i<16; i++) /* 每一个输入的4 bit*/ for (j = 0; j < 16; j++) /* 每一个4 bit的可能值~[0,16]*/ for (k = 0; k < 64; k++) /* 每一个输出bit的位置*/ { l = p[k] - 1; /* p[k]最小值为l,l从0开始*/ if ((l >> 2) != i) /* l~[0,63],每四位一组,共十六组,因此要l>>2*/ continue; if (!(j & nibblebit[l & 3])) /*确定第l~[0,63]位是一个四位组中的第几位*/ continue; m = k & 07; /*确定第k~[0,63]位是一个字节中的第几位*/ perm[i][j][k>>3] |= bytebit[m]; } } iter(num,inblock,outblock) /* 完成第num层的变换*/ int num; char *inblock, *outblock; /* 64 bits */ { char fret[4]; /* 放置f(R[i-1],key)的返回值*/ register char *ib, *ob, *fb; ob = outblock; ib = &inblock[4]; /*右边32位*/ f(ib, num, fret); *ob++ = *ib++; /* L[i] = R[i-1] */ *ob++ = *ib++; *ob++ = *ib++; *ob++ = *ib++; ib = inblock; fb = fret; /* R[i]=L[i] XOR f(R[i-1],key) */ *ob++ = *ib++ ^ *fb++; *ob++ = *ib++ ^ *fb++; *ob++ = *ib++ ^ *fb++; *ob++ = *ib++ ^ *fb++; } f(right,num,fret) /* 完成num层的f()函数*/ char *right, *fret; /* 32 bits */ int num; { register char *kb, *rb, *bb; char bigright[6]; char result[6]; char preout[4]; kb = kn[num]; bb = bigright; rb = result; expand(right,bb); /*扩展成48bit*/ *rb++ = *bb++ ^ *kb++; *rb++ = *bb++ ^ *kb++; /*Kn与Rn异或操作*/ *rb++ = *bb++ ^ *kb++; *rb++ = *bb++ ^ *kb++; *rb++ = *bb++ ^ *kb++; *rb++ = *bb++ ^ *kb++; contract(result,preout); /*用s盒得到32bit输出*/ perm32(preout,fret); /*最后换位*/ } perm32(inblock,outblock) /* 单纯换位*/ char *inblock,*outblock; /* of the f crypto function */ { register int j; register char *ib, *ob; register char *q; ob = outblock; /* 把输出的块清零*/ *ob++ = 0; *ob++ = 0; *ob++ = 0; *ob++ = 0; ib=inblock; for (j=0; j<4; j++, ib++) /* 输入的每一字节*/ { q = p32[j][*ib & 0377]; ob = outblock; /* 每一输出的字节*/ *ob++ |= *q++; *ob++ |= *q++; *ob++ |= *q++; *ob++ |= *q++; } } expand(right,bigright) /* 用E变换矩阵完成32---48扩展换位*/ char *right,*bigright; /* right 32 bit, bigright 48 bit */ { register char *bb, *r, r0, r1, r2, r3; bb = bigright; r = right; r0 = *r++; r1 = *r++; r2 = *r++; r3 = *r++; *bb++ = ((r3 & 0001) << 7) | /* 32 */ ((r0 & 0370) >> 1) | /* 1 2 3 4 5 */ ((r0 & 0030) >> 3); /* 4 5 */ *bb++ = ((r0 & 0007) << 5) | /* 6 7 8 */ ((r1 & 0200) >> 3) | /* 9 */ ((r0 & 0001) << 3) | /* 8 */ ((r1 & 0340) >> 5); /* 9 10 11 */ *bb++ = ((r1 & 0030) << 3) | /* 12 13 */ ((r1 & 0037) << 1) | /* 12 13 14 15 16 */ ((r2 & 0200) >> 7); /* 17 */ *bb++ = ((r1 & 0001) << 7) | /* 16 */ ((r2 & 0370) >> 1) | /* 17 18 19 20 21 */ ((r2 & 0030) >> 3); /* 20 21 */ *bb++ = ((r2 & 0007) << 5) | /* 22 23 24 */ ((r3 & 0200) >> 3) | /* 25 */ ((r2 & 0001) << 3) | /* 24 */ ((r3 & 0340) >> 5); /* 25 26 27 */ *bb++ = ((r3 & 0030) << 3) | /* 28 29 */ ((r3 & 0037) << 1) | /* 28 29 30 31 32 */ ((r0 & 0200) >> 7); /* 1 */ } contract(in48,out32) /* 48位经s盒后,输出32位*/ char *in48,*out32; { register char *c; register char *i; register int i0, i1, i2, i3, i4, i5; i = in48; i0 = *i++; i1 = *i++; i2 = *i++; i3 = *i++; i4 = *i++; i5 = *i++; c = out32; *c++ = s[0][07777 & ((i0 << 4) | ((i1 >> 4) & 017 ))]; *c++ = s[1][07777 & ((i1 << 8) | ( i2 & 0377 ))]; *c++ = s[2][07777 & ((i3 << 4) | ((i4 >> 4) & 017 ))]; *c++ = s[3][07777 & ((i4 << 8) | ( i5 & 0377 ))]; } /************************ 以上是DES 的全部算法************************/ char *inname, *outname; FILE *infile, *outfile; int encrypting; char buf[512]; char keyx[9],keyy[9]; char *malloc(), *strcpy(), *strcat(); main(argc, argv) int argc; char *argv[]; { register char *u; char *filename; if (argc < 2) /* 命令行是否给出了文件名? */ { fprintf(stderr, "Usage: des file ...\n"); exit(1); } for (++argv; --argc; ++argv) { inname = *argv; outname = filename = malloc((unsigned) strlen(inname) + 5); strcpy(filename, inname); u = &filename[strlen(filename) - 4]; /* 检查最后4个字符*/ encrypting = (strcmp(".des", u) != 0); if (!encrypting) *u = 0; /* 解密时输出文件去掉.des*/ else strcat(filename, ".des"); /* 加密时给输出文件加上.des*/ if ((infile = fopen(inname, "rb")) == NULL) { fprintf(stderr,"Can't read %s.\n", inname); exit(1); } if ((outfile = fopen(outname, "rb")) != NULL) { fprintf(stderr, "%s would be overwritten.\n",outname); exit(1); } if ((outfile = fopen(outname, "wb")) == NULL) { fprintf(stderr,"Can't write %s.\n", outname); exit(1); } key_get("Type password for "); for (;;) { strcpy(keyx, keyy); key_get("Verify password for "); if (strcmp(keyx, keyy) == 0) break; } desinit(keyx); /*建立用于des运算的矩阵*/ if (pfile() == 0) unlink(inname); else fprintf(stderr, "%s: I/O Error -- File unchanged\n", inname); fclose(outfile); fclose(infile); } exit(0); } key_get(mes) /*输入密码*/ char *mes; { register int i, j; char linebuf[256]; int count; // for (i=0; i<14; i++) keyy[i]=0; printf("%s%s: ", mes, inname); fflush(stdout); /*使用read(),fread()前先刷新文件*/ count = read(0, linebuf, 256); /* 输入密码*/ printf("\n"); linebuf[count] = 0; /* 添加一个0作为字符串的结束*/ if (linebuf[count-1] == '\n') { linebuf[count-1] = 0; /*把"\n"变成0*/ count--; } if (count > 8) count = 8; /* 只取 8 字节 */ for (i = j = 0; count--;) keyy[i++] = linebuf[j++]; } pfile() /* 文件加密处理*/ { register int m, nsave; register char *b; int j; while (m = fread(buf, 1, 512, infile)) { if ((nsave = m) < 0) /* 读出错*/ return(-1); for (b=buf; m>0;m -= 8, b += 8) /* 加密解密一个缓冲区的块*/ { if (encrypting) { if (m<8) /* 不够一块---64 bits */ { for (j=0; j<8-m; j++) b[m+j]=garbage(); /* 填充不够一块的部分*/ nsave += 8-m; /* 把nave凑成8的整数倍*/ } else j=0; /* 不足8字节时的缺额数量j=8-m*/ endes(b,b); } else /* 解密*/ { if (m < 8) deout(b, 1); /* 最后的几个字节*/ else { dedes(b, b); /* 解密一个块*/ deout(b, 0); /*输出到文件*/ } } } if (encrypting) if (fwrite(buf, 1, nsave, outfile) != nsave) return(-1); } /* 加密解密文件完成*/ if (encrypting) fputc(8 - j, outfile); /* 8-j=最后一个块的有效字节数*/ return(0); } int outcount = 0; deout(block,flag) /* 根据flag标志来决定输出到文件的内容*/ char *block,flag; /* char*block 64-bit 块, flag=1:处理的块是文件的最后的块 flag=0:处理的块不是文件的最后的块*/ { static char last[8]; /*static char last[8] 前一个输入块,静态变量,初始化为零*/ register int i; if (flag) /* 输出的最后的几个字节*/ { fwrite(last, 1, block[0] & 0377, outfile); /*block[0]包含内容"8-j*/ return; } if (outcount++) /* 以前是否处理过块,即输入的加密文件长度不到8字节*/ fwrite(last, 1, 8, outfile); for (i = 0; i < 8; i++) last[i] = block[i]; /* 复制块*/ } garbage() /* 产生一些数字用以填充不足8字节的块*/ /*产生数据随机性大一些,加密效果会更好*/ { return 0; } /*********************程序结束**************************/