ref: ad26dc48a6dc05da02f96e5f1e7b82de58ff5b2c
dir: /sys/src/libsec/port/aesCFB.c/
#include "os.h" #include <libsec.h> typedef ulong u32; void aesCFBencrypt(uchar *p, int len, AESstate *s) { u32 a, o = s->offset; while(len > 0){ if(o % 16){ Odd: a = (s->ivec[o++ % 16] ^= *p), *p++ = a, len--; continue; } aes_encrypt(s->ekey, s->rounds, s->ivec, s->ivec); if(len < 16 || ((p-(uchar*)0) & 3) != 0) goto Odd; ((u32*)p)[0] = (((u32*)s->ivec)[0] ^= ((u32*)p)[0]); ((u32*)p)[1] = (((u32*)s->ivec)[1] ^= ((u32*)p)[1]); ((u32*)p)[2] = (((u32*)s->ivec)[2] ^= ((u32*)p)[2]); ((u32*)p)[3] = (((u32*)s->ivec)[3] ^= ((u32*)p)[3]); o += 16, p += 16, len -= 16; } s->offset = o; } void aesCFBdecrypt(uchar *p, int len, AESstate *s) { u32 a, o = s->offset; while(len > 0){ if(o % 16){ Odd: a = *p, *p++ ^= s->ivec[o % 16], s->ivec[o++ % 16] = a, len--; continue; } aes_encrypt(s->ekey, s->rounds, s->ivec, s->ivec); if(len < 16 || ((p-(uchar*)0) & 3) != 0) goto Odd; a = ((u32*)p)[0], ((u32*)p)[0] ^= ((u32*)s->ivec)[0], ((u32*)s->ivec)[0] = a; a = ((u32*)p)[1], ((u32*)p)[1] ^= ((u32*)s->ivec)[1], ((u32*)s->ivec)[1] = a; a = ((u32*)p)[2], ((u32*)p)[2] ^= ((u32*)s->ivec)[2], ((u32*)s->ivec)[2] = a; a = ((u32*)p)[3], ((u32*)p)[3] ^= ((u32*)s->ivec)[3], ((u32*)s->ivec)[3] = a; o += 16, p += 16, len -= 16; } s->offset = o; }