B-SIDE

A CTF challenge series with fun puzzles to enjoy every day — B-SIDE

What is B-SIDE?

This side program features challenges with a different flavor from Daily AlpacaHack. We publish harder or more unconventional challenges from time to time.

Join Anytime

Solve each challenge within its time window to appear on the leaderboard.

Not a Competition

Discussion with friends or AI is welcome (account sharing is prohibited).

Solution Sharing Rules

Sharing solutions is allowed only after the challenge period has ended.

New to CTFs?

This program features higher difficulty and unconventional challenges. Try the beginner-friendly Daily AlpacaHack first to warm up.

View Daily AlpacaHack

Solve stats

No solved challenges yet.

Today's Challenge

No challenge is currently active.

Leaderboard

Period

Upcoming challenges reveal the , , and in advance.

Aug 2026

Solved

Unsolved

Upcoming

Mon

Tue

Wed

Thu

Fri

Sat

Sun

ark

nodebox

Misc

Very Very Hard

14 solves

Coming soon

Go to Daily AlpacaHack

Writeups

Writeup for nodebox

claustra01

nodebox

2026/08/03 06:18

Writeup for Life is probably full of bugs

umineko

Life is probably full of bugs

2026/07/28 08:56

Writeup for Long Flag Printer 2026

baumroll1234

Long Flag Printer 2026

2026/07/22 03:07

Writeup for kappa maki

colza

author

kappa maki

2026/07/21 07:31

Writeup for kappa maki

ojun

kappa maki

2026/07/18 09:11

Writeup for Re:Small e

umineko

Re:Small e

2026/07/16 03:53

Writeup for invisible-grep

kirehash

invisible-grep

2026/07/14 13:25

Writeup for missing ✌️

goroshirow

missing ✌️

2026/07/07 15:19

Writeup for New Directory

umineko

New Directory

2026/07/07 10:13

Writeup for InstaTalk

tchen

author

InstaTalk

2026/07/06 07:37

Rows:

Long Flag Printer 2026

Topic: NetworkReleased: Jul 17, 2026

29 solves

Misc

Medium5.0

minaminao

Tags

USER	SOLVED AT
hori	2026/08/03 01:07
a2zog	2026/08/02 22:18
nirvana	2026/08/01 09:01
fukayatti0	2026/07/27 06:24
labpump	2026/07/26 09:39
baumroll1234	2026/07/21 13:04
sniperthrilla	2026/07/21 07:03
ahnmo	2026/07/21 01:10
serioton	2026/07/20 22:59
nomeaning	2026/07/20 14:54
bono	2026/07/20 10:07
shiragi	2026/07/20 05:44
tadanobutubutu	2026/07/19 22:26
toomer	2026/07/18 20:47
nakamulab	2026/07/18 20:38
tyage	2026/07/18 12:17
kurokane-isumi	2026/07/18 08:38
kurgm	2026/07/18 06:46
apender	2026/07/18 06:34
cat22222	2026/07/18 04:03
pppp4649	2026/07/18 03:10
rsk0315	2026/07/18 02:38
suan5uan	2026/07/17 10:02
stackotter	2026/07/17 02:17
syn9	2026/07/16 22:35

Rows:

description solves writeups