asepharyana
7a6e717c28
- Deleted all previous dummy docs (defcon-quals-2024, infra/cloudflare-525, debugging/websocket-timeout, template, docs/*, notes/*, research/*) - Added 14 Gemastik warmup writeups covering encoding, stego, web, pwn, crypto - ch13: RSA small factors; ch14: RSA special integers via paper-search (GCD with paper appendix primes) - All flags recovered and documented with solution methods
663 B
663 B
title, event, challenge, category, points, difficulty, flag
| title | event | challenge | category | points | difficulty | flag |
|---|---|---|---|---|---|---|
| Back and Forth — XOR | GEMASTIK 2026 Warmup | Back and Forth | 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}