CHAPTER 79. “QR9”: RUBIK’S CUBE INSPIRED AMATEUR CRYPTO-ALGORITHM CHAPTER 79. “QR9”: RUBIK’S CUBE INSPIRED AMATEUR CRYPTO-ALGORITHM
...this code is placing the contents of the internal array to the cube global array via theset_bit()function,butin a different
order! Now the counter of the first loop is in the range of 7 to 0,decrementingat each iteration!
The C code representation looks like:
void rotate1 (int v)
{
bool tmp[8][8]; // internal array
int i, j;
for (i=0; i<8; i++)
for (j=0; j<8; j++)
tmp[i][j]=get_bit (i, j, v);for (i=0; i<8; i++)
for (j=0; j<8; j++)
set_bit (j, 7-i, v, tmp[x][y]);
};
Not very understandable, but if we take a look atrotate2()function:
.text:005410E0 rotate2 proc near
.text:005410E0
.text:005410E0 internal_array_64 = byte ptr -40h
.text:005410E0 arg_0 = dword ptr 4
.text:005410E0
.text:005410E0 sub esp, 40h
.text:005410E3 push ebx
.text:005410E4 push ebp
.text:005410E5 mov ebp, [esp+48h+arg_0]
.text:005410E9 push esi
.text:005410EA push edi
.text:005410EB xor edi, edi ; loop 1 counter
.text:005410ED lea ebx, [esp+50h+internal_array_64]
.text:005410F1
.text:005410F1 loc_5410F1:
.text:005410F1 xor esi, esi ; loop 2 counter
.text:005410F3
.text:005410F3 loc_5410F3:
.text:005410F3 push esi ; loop 2 counter
.text:005410F4 push edi ; loop 1 counter
.text:005410F5 push ebp ; arg_0
.text:005410F6 call get_bit
.text:005410FB add esp, 0Ch
.text:005410FE mov [ebx+esi], al ; store to internal array
.text:00541101 inc esi ; increment loop 1 counter
.text:00541102 cmp esi, 8
.text:00541105 jl short loc_5410F3
.text:00541107 inc edi ; increment loop 2 counter
.text:00541108 add ebx, 8
.text:0054110B cmp edi, 8
.text:0054110E jl short loc_5410F1
.text:00541110 lea ebx, [esp+50h+internal_array_64]
.text:00541114 mov edi, 7 ; loop 1 counter is initial state 7
.text:00541119
.text:00541119 loc_541119:
.text:00541119 xor esi, esi ; loop 2 counter
.text:0054111B
.text:0054111B loc_54111B:
.text:0054111B mov al, [ebx+esi] ; get byte from internal array
.text:0054111E push eax
.text:0054111F push edi ; loop 1 counter
.text:00541120 push esi ; loop 2 counter
.text:00541121 push ebp ; arg_0
.text:00541122 call set_bit
.text:00541127 add esp, 10h
.text:0054112A inc esi ; increment loop 2 counter
.text:0054112B cmp esi, 8
.text:0054112E jl short loc_54111B
.text:00541130 dec edi ; decrement loop 2 counter