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B-SIDE

A daily CTF challenge with a fun new puzzle every day

What is B-SIDE?

This side program features challenges with a different flavor from Daily AlpacaHack. We publish one harder or more unconventional challenge every few days.

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.

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Today's Challenge
theoremoon
ECRSA
Crypto
Very Hard
33 solves
Submissions (latest 3)
xnmhuveb

SOLVED!

Feb 19, 12:47 AM

Leaderboard
Topics and categories are revealed in advance for upcoming challenges.

Feb 2026

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Mon
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26
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31
1-4
st98
Inu Profile
Web
Very Hard
82 solves
 
st98
Inu Profile
Web
Very Hard
82 solves
5-8
chocorusk
HellCouple
Crypto
Very Hard
62 solves
9-12
minaminao
invisible-grep
Misc
Very Hard
32 solves
13-16
k0080
ret2basics
Pwn
Very Hard
34 solves
 
k0080
ret2basics
Pwn
Very Hard
34 solves
17-20
theoremoon
ECRSA
Crypto
Very Hard
33 solves
21-24
chocorusk
Planned topicWindows
Rev
Very Hard
 
Planned topicWindows
Rev
Very Hard
25
Coming soon
26
Coming soon
27
Coming soon
28
Coming soon
1
Coming soon

Writeups

Writeup for ret2basics

kakur41

ja
ret2basics

2 days ago

Writeup for invisible-grep

Writeup for HellCouple

Writeup for HellCouple

Writeup for Inu Profile

Writeup for HellCouple

ja

last week

Writeup for HellCouple

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