desCBC.c (1097B)
1 #include "os.h" 2 #include <mp.h> 3 #include <libsec.h> 4 5 /* Because of the way that non multiple of 8 */ 6 /* buffers are handled, the decryptor must */ 7 /* be fed buffers of the same size as the */ 8 /* encryptor */ 9 10 11 /* If the length is not a multiple of 8, I encrypt */ 12 /* the overflow to be compatible with lacy's cryptlib */ 13 void 14 desCBCencrypt(uchar *p, int len, DESstate *s) 15 { 16 uchar *p2, *ip, *eip; 17 18 for(; len >= 8; len -= 8){ 19 p2 = p; 20 ip = s->ivec; 21 for(eip = ip+8; ip < eip; ) 22 *p2++ ^= *ip++; 23 block_cipher(s->expanded, p, 0); 24 memmove(s->ivec, p, 8); 25 p += 8; 26 } 27 28 if(len > 0){ 29 ip = s->ivec; 30 block_cipher(s->expanded, ip, 0); 31 for(eip = ip+len; ip < eip; ) 32 *p++ ^= *ip++; 33 } 34 } 35 36 void 37 desCBCdecrypt(uchar *p, int len, DESstate *s) 38 { 39 uchar *ip, *eip, *tp; 40 uchar tmp[8]; 41 42 for(; len >= 8; len -= 8){ 43 memmove(tmp, p, 8); 44 block_cipher(s->expanded, p, 1); 45 tp = tmp; 46 ip = s->ivec; 47 for(eip = ip+8; ip < eip; ){ 48 *p++ ^= *ip; 49 *ip++ = *tp++; 50 } 51 } 52 53 if(len > 0){ 54 ip = s->ivec; 55 block_cipher(s->expanded, ip, 0); 56 for(eip = ip+len; ip < eip; ) 57 *p++ ^= *ip++; 58 } 59 }