Project Sekai - ✅-reverse-mazinrev

MazinRev - 500 points

Category: Reverse Description: > "You must take your opponent into a deep dark forest where 2+2=5".

- Mikhail Tal

The challenge was made based on "Tal" mindset, escape from that forest. Author : 0xc001 Files:

https://ctf.gdgalgiers.com/files/3539864a242b29ce2b26378e130907c9/mazinrev?token=eyJ1c2VyX2lkIjo0MzksInRlYW1faWQiOjE3NSwiZmlsZV9pZCI6NTB9.Y0BpbQ.QCIveFMHpSqIJT9AXEzAq2NKQ0g

Tags: No tags.

Sutx pinned a message to this channel. 10/07/2022 11:01 AM

@TheBadGod wants to collaborate

start at 5, goal is at 6, need to figure out how to encode the sol

##############6
##############2
########2322#22
2322####2##222#
2##222##3####4#
3####3##224####
224##2###2#####
#2##422#22#####
#5####222######
########4######

void __fastcall go_through(idk *a1)
{
  while ( (a1->current_tile == 2 || a1->current_tile == 3 || a1->current_tile == 4) && a1->char_index <= 7u )
  {
    a1->current_tile = check_move(a1);
    ++a1->char_index;
  }
}

mh, but we need to do it in 8 or less steps.... (char_index <= 7)

12:11

    initially facing up on 5

    ] => rotate left on 3s
    [ => rotate left on 2s
    \ => rotate left on 4s
    Y => rotate left

    U => rotate right on 3s
    S => rotate right on 2s
    R => rotate right on 4s
    Q => rotate right

    M => move on 3s
    K => move on 2s
    J => move on 4s
    I => move

    GOAL on 6

rotate + move are 2 steps? and whats the second thing

the second thing?

3s

the on xs?

12:14

that's the tile numbers

oh

TheBadGod

start at 5, goal is at 6, need to figure out how to encode the sol

##############6
##############2
########2322#22
2322####2##222#
2##222##3####4#
3####3##224####
224##2###2#####
#2##422#22#####
#5####222######
########4######

see here

12:15

so U only works on tiles with 3 on them

doesnt seem likely in 8 steps, or i understand wrong, e.g. you need IKK to move up before turn left

yeah, thought about some exploits (namely the 2 on the very far is very sus, because in the 1d array, the field just to the left is also walkable, but 2 beneath the goal)

12:17

but they seem to check that x!=0 when going left

oh i see, ill read code a bit

decompilation as far as i have it (main thing is go_through afaict)

mazinrev.c

20.8 KB

OOOOH

12:32

the char index is reset when we use another char

12:32

so we need to make an algo which can solve the maze in 8 chars

TheBadGod

    initially facing up on 5

    ] => rotate left on 3s
    [ => rotate left on 2s
    \ => rotate left on 4s
    Y => rotate left

    U => rotate right on 3s
    S => rotate right on 2s
    R => rotate right on 4s
    Q => rotate right

    M => move on 3s
    K => move on 2s
    J => move on 4s
    I => move

    GOAL on 6

and these additional instructions

    e => reset if on 3s
    c => reset if on 2s
    b => reset if on 4s
    a => reset

12:34

we start where the 5 is, but it's replaced with a 2 and we start facing up (edited)

oh

so I I Q I Q Q a would land us on 4, then reset, then we'd land on the 3 and face down