# Olympic CTF 2014: As seen on DEFCON
**Category:** Nopsleigh (Pwn)
> `EBFE` is to x86 as **____** is to ARM64.
This is a reference to [DEF CON 2006’s trivia challenge](http://nopsr.us/ctf2006prequal/walk-trivia.html#500) which went like this:
> `EBFE` is to x86 as **____** is to PowerPC.
This time we have to find the ARM64 equivalent. Let’s see what kind of instruction `EBFE` is:
$ echo -ne '\xEB\xFE' | ndisasm -
00000000 EBFE jmp short 0x0
Okay, so `\xEB\xFE` is a `jmp` instruction. ARM doesn’t have `jmp` instructions though — [it uses `b` instructions (branches) instead](http://www.heyrick.co.uk/armwiki/B). Let’s see which opcode `b` maps to:
$ echo 'b .' | aarch64-linux-gnu-as
$ aarch64-linux-gnu-objdump -d a.out
a.out: file format elf64-littleaarch64
Disassembly of section .text:
0: 14000000 b 0 <.text>
So the 32-bit instruction word for `b` is `0x14000000`. Since ARM64 is little-endian, this becomes `00000014`.
The answer is `00000014`.
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