202 lines
9.3 KiB
C
202 lines
9.3 KiB
C
/*
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* _cast5.c
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* Implementation of the CAST5 cipher
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*
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* Copyright 2002-2004 by Bob Mathews
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*
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* This library is free software; you can redistribute it and/or modify
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* it under the same terms as Perl itself.
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*/
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#include "cast5.h"
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#define B0(x) (((x) >> 24) & 0xff)
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#define B1(x) (((x) >> 16) & 0xff)
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#define B2(x) (((x) >> 8) & 0xff)
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#define B3(x) ( (x) & 0xff)
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#ifdef GCC_X86
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#define ROL(x,y) asm("rol %1,%0" : "=r" (x) : "c" ((U8)y), "0" (x))
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#else
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#define ROL(x,y) ( (x) = ((x) << (y)) | (((x) & 0xffffffffuL) >> (32-(y))) )
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#endif
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#define CAST5_STEP1(Km, Kr, I, L, R) \
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I = Km + R; ROL(I, Kr); \
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L ^= ((S1[B0(I)] ^ S2[B1(I)]) - S3[B2(I)]) + S4[B3(I)];
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#define CAST5_STEP2(Km, Kr, I, L, R) \
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I = Km ^ R; ROL(I, Kr); \
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L ^= ((S1[B0(I)] - S2[B1(I)]) + S3[B2(I)]) ^ S4[B3(I)];
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#define CAST5_STEP3(Km, Kr, I, L, R) \
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I = Km - R; ROL(I, Kr); \
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L ^= ((S1[B0(I)] + S2[B1(I)]) ^ S3[B2(I)]) - S4[B3(I)];
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#define CHAR_TO_WORD(c) ( (((U32) (c)[0] & 0xff) << 24) | \
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(((U32) (c)[1] & 0xff) << 16) | \
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(((U32) (c)[2] & 0xff) << 8) | \
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((U32) (c)[3] & 0xff) )
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#define WORD_TO_CHAR(w,c) ( (c)[0] = B0(w), (c)[1] = B1(w), \
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(c)[2] = B2(w), (c)[3] = B3(w) )
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void cast5_init(struct cast5_state *cast5, char *key, int keylen)
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{
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int i;
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U32 a, b, c, d, e;
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/* use volatile so compiler won't optimize away the key clear */
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volatile char padded[16];
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cast5->rounds = (keylen <= 10) ? 12 : 16;
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if (keylen >= 16) {
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a = CHAR_TO_WORD(key);
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b = CHAR_TO_WORD(key+4);
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c = CHAR_TO_WORD(key+8);
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d = CHAR_TO_WORD(key+12);
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}
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else {
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for (i = 0; i < keylen; i++) padded[i] = key[i];
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for (; i < 16; i++) padded[i] = 0;
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a = CHAR_TO_WORD(padded);
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b = CHAR_TO_WORD(padded+4);
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c = CHAR_TO_WORD(padded+8);
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d = CHAR_TO_WORD(padded+12);
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for (i = 0; i < 16; i++) padded[i] = 0;
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}
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e = c;
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a ^= S5[B1(d)] ^ S6[B3(d)] ^ S7[B0(d)] ^ S8[B2(d)] ^ S7[B0(e)];
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c ^= S5[B0(a)] ^ S6[B2(a)] ^ S7[B1(a)] ^ S8[B3(a)] ^ S8[B2(e)];
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d ^= S5[B3(c)] ^ S6[B2(c)] ^ S7[B1(c)] ^ S8[B0(c)] ^ S5[B1(e)];
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b ^= S5[B2(d)] ^ S6[B1(d)] ^ S7[B3(d)] ^ S8[B0(d)] ^ S6[B3(e)];
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cast5->mask_key[0]=S5[B0(d)]^S6[B1(d)]^S7[B3(c)]^S8[B2(c)]^S5[B2(a)];
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cast5->mask_key[1]=S5[B2(d)]^S6[B3(d)]^S7[B1(c)]^S8[B0(c)]^S6[B2(c)];
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cast5->mask_key[2]=S5[B0(b)]^S6[B1(b)]^S7[B3(a)]^S8[B2(a)]^S7[B1(d)];
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cast5->mask_key[3]=S5[B2(b)]^S6[B3(b)]^S7[B1(a)]^S8[B0(a)]^S8[B0(b)];
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e = a;
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d ^= S5[B1(c)] ^ S6[B3(c)] ^ S7[B0(c)] ^ S8[B2(c)] ^ S7[B0(e)];
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a ^= S5[B0(d)] ^ S6[B2(d)] ^ S7[B1(d)] ^ S8[B3(d)] ^ S8[B2(e)];
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c ^= S5[B3(a)] ^ S6[B2(a)] ^ S7[B1(a)] ^ S8[B0(a)] ^ S5[B1(e)];
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b ^= S5[B2(c)] ^ S6[B1(c)] ^ S7[B3(c)] ^ S8[B0(c)] ^ S6[B3(e)];
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cast5->mask_key[4]=S5[B3(d)]^S6[B2(d)]^S7[B0(b)]^S8[B1(b)]^S5[B0(c)];
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cast5->mask_key[5]=S5[B1(d)]^S6[B0(d)]^S7[B2(b)]^S8[B3(b)]^S6[B1(b)];
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cast5->mask_key[6]=S5[B3(a)]^S6[B2(a)]^S7[B0(c)]^S8[B1(c)]^S7[B3(d)];
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cast5->mask_key[7]=S5[B1(a)]^S6[B0(a)]^S7[B2(c)]^S8[B3(c)]^S8[B3(a)];
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e = c;
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d ^= S5[B1(b)] ^ S6[B3(b)] ^ S7[B0(b)] ^ S8[B2(b)] ^ S7[B0(e)];
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c ^= S5[B0(d)] ^ S6[B2(d)] ^ S7[B1(d)] ^ S8[B3(d)] ^ S8[B2(e)];
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b ^= S5[B3(c)] ^ S6[B2(c)] ^ S7[B1(c)] ^ S8[B0(c)] ^ S5[B1(e)];
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a ^= S5[B2(b)] ^ S6[B1(b)] ^ S7[B3(b)] ^ S8[B0(b)] ^ S6[B3(e)];
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cast5->mask_key[8] =S5[B3(d)]^S6[B2(d)]^S7[B0(a)]^S8[B1(a)]^S5[B1(b)];
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cast5->mask_key[9] =S5[B1(d)]^S6[B0(d)]^S7[B2(a)]^S8[B3(a)]^S6[B0(a)];
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cast5->mask_key[10]=S5[B3(c)]^S6[B2(c)]^S7[B0(b)]^S8[B1(b)]^S7[B2(d)];
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cast5->mask_key[11]=S5[B1(c)]^S6[B0(c)]^S7[B2(b)]^S8[B3(b)]^S8[B2(c)];
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e = d;
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b ^= S5[B1(c)] ^ S6[B3(c)] ^ S7[B0(c)] ^ S8[B2(c)] ^ S7[B0(e)];
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d ^= S5[B0(b)] ^ S6[B2(b)] ^ S7[B1(b)] ^ S8[B3(b)] ^ S8[B2(e)];
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c ^= S5[B3(d)] ^ S6[B2(d)] ^ S7[B1(d)] ^ S8[B0(d)] ^ S5[B1(e)];
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a ^= S5[B2(c)] ^ S6[B1(c)] ^ S7[B3(c)] ^ S8[B0(c)] ^ S6[B3(e)];
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cast5->mask_key[12]=S5[B0(c)]^S6[B1(c)]^S7[B3(d)]^S8[B2(d)]^S5[B3(b)];
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cast5->mask_key[13]=S5[B2(c)]^S6[B3(c)]^S7[B1(d)]^S8[B0(d)]^S6[B3(d)];
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cast5->mask_key[14]=S5[B0(a)]^S6[B1(a)]^S7[B3(b)]^S8[B2(b)]^S7[B0(c)];
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cast5->mask_key[15]=S5[B2(a)]^S6[B3(a)]^S7[B1(b)]^S8[B0(b)]^S8[B1(a)];
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e = c;
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b ^= S5[B1(a)] ^ S6[B3(a)] ^ S7[B0(a)] ^ S8[B2(a)] ^ S7[B0(e)];
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c ^= S5[B0(b)] ^ S6[B2(b)] ^ S7[B1(b)] ^ S8[B3(b)] ^ S8[B2(e)];
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a ^= S5[B3(c)] ^ S6[B2(c)] ^ S7[B1(c)] ^ S8[B0(c)] ^ S5[B1(e)];
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d ^= S5[B2(a)] ^ S6[B1(a)] ^ S7[B3(a)] ^ S8[B0(a)] ^ S6[B3(e)];
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cast5->rot_key[0]=(S5[B0(a)]^S6[B1(a)]^S7[B3(c)]^S8[B2(c)]^S5[B2(b)])&31;
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cast5->rot_key[1]=(S5[B2(a)]^S6[B3(a)]^S7[B1(c)]^S8[B0(c)]^S6[B2(c)])&31;
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cast5->rot_key[2]=(S5[B0(d)]^S6[B1(d)]^S7[B3(b)]^S8[B2(b)]^S7[B1(a)])&31;
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cast5->rot_key[3]=(S5[B2(d)]^S6[B3(d)]^S7[B1(b)]^S8[B0(b)]^S8[B0(d)])&31;
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e = b;
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a ^= S5[B1(c)] ^ S6[B3(c)] ^ S7[B0(c)] ^ S8[B2(c)] ^ S7[B0(e)];
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b ^= S5[B0(a)] ^ S6[B2(a)] ^ S7[B1(a)] ^ S8[B3(a)] ^ S8[B2(e)];
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c ^= S5[B3(b)] ^ S6[B2(b)] ^ S7[B1(b)] ^ S8[B0(b)] ^ S5[B1(e)];
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d ^= S5[B2(c)] ^ S6[B1(c)] ^ S7[B3(c)] ^ S8[B0(c)] ^ S6[B3(e)];
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cast5->rot_key[4]=(S5[B3(a)]^S6[B2(a)]^S7[B0(d)]^S8[B1(d)]^S5[B0(c)])&31;
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cast5->rot_key[5]=(S5[B1(a)]^S6[B0(a)]^S7[B2(d)]^S8[B3(d)]^S6[B1(d)])&31;
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cast5->rot_key[6]=(S5[B3(b)]^S6[B2(b)]^S7[B0(c)]^S8[B1(c)]^S7[B3(a)])&31;
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cast5->rot_key[7]=(S5[B1(b)]^S6[B0(b)]^S7[B2(c)]^S8[B3(c)]^S8[B3(b)])&31;
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e = c;
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a ^= S5[B1(d)] ^ S6[B3(d)] ^ S7[B0(d)] ^ S8[B2(d)] ^ S7[B0(e)];
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c ^= S5[B0(a)] ^ S6[B2(a)] ^ S7[B1(a)] ^ S8[B3(a)] ^ S8[B2(e)];
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d ^= S5[B3(c)] ^ S6[B2(c)] ^ S7[B1(c)] ^ S8[B0(c)] ^ S5[B1(e)];
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b ^= S5[B2(d)] ^ S6[B1(d)] ^ S7[B3(d)] ^ S8[B0(d)] ^ S6[B3(e)];
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cast5->rot_key[8] =(S5[B3(a)]^S6[B2(a)]^S7[B0(b)]^S8[B1(b)]^S5[B1(d)])&31;
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cast5->rot_key[9] =(S5[B1(a)]^S6[B0(a)]^S7[B2(b)]^S8[B3(b)]^S6[B0(b)])&31;
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cast5->rot_key[10]=(S5[B3(c)]^S6[B2(c)]^S7[B0(d)]^S8[B1(d)]^S7[B2(a)])&31;
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cast5->rot_key[11]=(S5[B1(c)]^S6[B0(c)]^S7[B2(d)]^S8[B3(d)]^S8[B2(c)])&31;
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e = a;
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d ^= S5[B1(c)] ^ S6[B3(c)] ^ S7[B0(c)] ^ S8[B2(c)] ^ S7[B0(e)];
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a ^= S5[B0(d)] ^ S6[B2(d)] ^ S7[B1(d)] ^ S8[B3(d)] ^ S8[B2(e)];
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c ^= S5[B3(a)] ^ S6[B2(a)] ^ S7[B1(a)] ^ S8[B0(a)] ^ S5[B1(e)];
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b ^= S5[B2(c)] ^ S6[B1(c)] ^ S7[B3(c)] ^ S8[B0(c)] ^ S6[B3(e)];
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cast5->rot_key[12]=(S5[B0(c)]^S6[B1(c)]^S7[B3(a)]^S8[B2(a)]^S5[B3(d)])&31;
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cast5->rot_key[13]=(S5[B2(c)]^S6[B3(c)]^S7[B1(a)]^S8[B0(a)]^S6[B3(a)])&31;
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cast5->rot_key[14]=(S5[B0(b)]^S6[B1(b)]^S7[B3(d)]^S8[B2(d)]^S7[B0(c)])&31;
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cast5->rot_key[15]=(S5[B2(b)]^S6[B3(b)]^S7[B1(d)]^S8[B0(d)]^S8[B1(b)])&31;
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} /* cast5_init */
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void cast5_encrypt(struct cast5_state *cast5, char *in, char *out)
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{
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U32 tmp, left, right;
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left = CHAR_TO_WORD(in);
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right = CHAR_TO_WORD(in+4);
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CAST5_STEP1(cast5->mask_key[0], cast5->rot_key[0], tmp, left, right);
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CAST5_STEP2(cast5->mask_key[1], cast5->rot_key[1], tmp, right, left);
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CAST5_STEP3(cast5->mask_key[2], cast5->rot_key[2], tmp, left, right);
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CAST5_STEP1(cast5->mask_key[3], cast5->rot_key[3], tmp, right, left);
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CAST5_STEP2(cast5->mask_key[4], cast5->rot_key[4], tmp, left, right);
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CAST5_STEP3(cast5->mask_key[5], cast5->rot_key[5], tmp, right, left);
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CAST5_STEP1(cast5->mask_key[6], cast5->rot_key[6], tmp, left, right);
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CAST5_STEP2(cast5->mask_key[7], cast5->rot_key[7], tmp, right, left);
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CAST5_STEP3(cast5->mask_key[8], cast5->rot_key[8], tmp, left, right);
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CAST5_STEP1(cast5->mask_key[9], cast5->rot_key[9], tmp, right, left);
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CAST5_STEP2(cast5->mask_key[10], cast5->rot_key[10], tmp, left, right);
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CAST5_STEP3(cast5->mask_key[11], cast5->rot_key[11], tmp, right, left);
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if (cast5->rounds == 16) {
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CAST5_STEP1(cast5->mask_key[12], cast5->rot_key[12], tmp, left, right);
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CAST5_STEP2(cast5->mask_key[13], cast5->rot_key[13], tmp, right, left);
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CAST5_STEP3(cast5->mask_key[14], cast5->rot_key[14], tmp, left, right);
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CAST5_STEP1(cast5->mask_key[15], cast5->rot_key[15], tmp, right, left);
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}
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WORD_TO_CHAR(right, out);
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WORD_TO_CHAR(left, out+4);
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} /* cast5_encrypt */
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void cast5_decrypt(struct cast5_state *cast5, char *in, char *out)
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{
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U32 tmp, left, right;
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right = CHAR_TO_WORD(in);
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left = CHAR_TO_WORD(in+4);
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if (cast5->rounds == 16) {
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CAST5_STEP1(cast5->mask_key[15], cast5->rot_key[15], tmp, right, left);
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CAST5_STEP3(cast5->mask_key[14], cast5->rot_key[14], tmp, left, right);
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CAST5_STEP2(cast5->mask_key[13], cast5->rot_key[13], tmp, right, left);
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CAST5_STEP1(cast5->mask_key[12], cast5->rot_key[12], tmp, left, right);
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}
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CAST5_STEP3(cast5->mask_key[11], cast5->rot_key[11], tmp, right, left);
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CAST5_STEP2(cast5->mask_key[10], cast5->rot_key[10], tmp, left, right);
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CAST5_STEP1(cast5->mask_key[9], cast5->rot_key[9], tmp, right, left);
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CAST5_STEP3(cast5->mask_key[8], cast5->rot_key[8], tmp, left, right);
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CAST5_STEP2(cast5->mask_key[7], cast5->rot_key[7], tmp, right, left);
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CAST5_STEP1(cast5->mask_key[6], cast5->rot_key[6], tmp, left, right);
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CAST5_STEP3(cast5->mask_key[5], cast5->rot_key[5], tmp, right, left);
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CAST5_STEP2(cast5->mask_key[4], cast5->rot_key[4], tmp, left, right);
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CAST5_STEP1(cast5->mask_key[3], cast5->rot_key[3], tmp, right, left);
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CAST5_STEP3(cast5->mask_key[2], cast5->rot_key[2], tmp, left, right);
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CAST5_STEP2(cast5->mask_key[1], cast5->rot_key[1], tmp, right, left);
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CAST5_STEP1(cast5->mask_key[0], cast5->rot_key[0], tmp, left, right);
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WORD_TO_CHAR(left, out);
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WORD_TO_CHAR(right, out+4);
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} /* cast5_decrypt */
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/* end _cast5.c */
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