asepharyana
0de2458955
- Deleted all 14 dummy docs from DB + filesystem - Created 14 Gemastik warmup writeups + index via create_document API (DB-first) - ch1-ch12: encoding/stego/web/pwn basics - ch13: RSA small factors - ch14: RSA special integers via paper-search (GCD with paper appendix primes) - All 15 docs indexed and live at wiki.asepharyana.my.id
925 B
925 B
title, type, section, status, author, tags, path, created_at, updated_at, event, challenge, category, points, difficulty, flag
| title | type | section | status | author | tags | path | created_at | updated_at | event | challenge | category | points | difficulty | flag | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Back and Forth — XOR | writeup | writeups | published | asep |
|
writeups/gemastik-2026-warmup/ch8-back-and-forth.md | 2026-08-21T07:25:37.394Z | 2026-08-21T07:25:37.394Z | GEMASTIK 2026 Warmup | Back and Forth — XOR | reverse | 500 | easy | GEMASTIK19{x0r_it_back_4gain} |
Back and Forth (500 pts) — Reversing / XOR
File: chall.c
Flag di-XOR dengan kunci 1-byte 0x42. Balikkan dengan XOR lagi:
enc = [0x05, 0x07, 0x0f, 0x03, 0x11, 0x16, 0x0b, 0x09, 0x73, 0x7b, 0x39, 0x3a,
0x72, 0x30, 0x1d, 0x2b, 0x36, 0x1d, 0x20, 0x23, 0x21, 0x29, 0x1d, 0x76,
0x25, 0x23, 0x2b, 0x2c, 0x3f]
flag = "".join(chr(b ^ 0x42) for b in enc)
print(flag)
# GEMASTIK19{x0r_it_back_4gain}
Flag
GEMASTIK19{x0r_it_back_4gain}