Daily AlpacaHack

A daily CTF challenge with a fun new puzzle every day

What is Daily AlpacaHack?

We publish one simple, beginner-friendly or educational CTF challenge every day!

Join Anytime

Solve within 24 hours of release 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 24 hours have passed since release.

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Today's Challenge

Submissions (latest 3)

cyanos

SOLVED!

Feb 16, 7:46 PM

m200is

SOLVED!

Feb 16, 5:42 PM

tsuuko

SOLVED!

Feb 16, 5:12 PM

Leaderboard

Period

Try the first challenge

Is this your first CTF? Let's begin by tackling the first challenge released on Daily AlpacaHack.

Topics and categories are revealed in advance for upcoming challenges.

Jan 2026

Solved

Unsolved

Upcoming

Mon

Tue

Wed

Thu

Fri

Sat

Sun

kanon

one-p-rsa

Crypto

Easy

198 solves

soon-haari

RBG

Crypto

Very Hard

116 solves

admin

108

Misc

Easy

251 solves

admin

Happy New Year

Misc

Welcome

467 solves

kanon

super-tomato

Crypto

Easy

324 solves

hiikunz

Ruby Flag Checker

Rev

Easy

248 solves

minaminao

Fushigi Crawler

Web

Easy

279 solves

kurenaif

Encoding Basics

Misc

Crypto

Easy

269 solves

minaminao

jailiaj

Misc

Easy

239 solves

hiikunz

Square RSA

Crypto

Medium

206 solves

ark

secret-table

Web

Medium

228 solves

hiikunz

SwapSwap

Misc

Easy

240 solves

theoremoon

RSA2026

Crypto

Medium

186 solves

keymoon

crazython

Rev

Medium

165 solves

hiikunz

Basic Buffer Overflow

Pwn

Medium

158 solves

tchen

I wanna be the Admin

Web

Easy

225 solves

ark

free-comment

Misc

Hard

142 solves

hiikunz

Five Alpacas

Crypto

Easy

165 solves

k0080

Short Writer

Pwn

Hard

112 solves

minaminao

Base Length

Misc

Medium

140 solves

hiikunz

dice roll

Web

Medium

174 solves

chocorusk

ChaChaCha

Crypto

Medium

146 solves

k0080

system-v

Rev

Hard

112 solves

ark

dockerstack

Misc

Easy

163 solves

hiikunz

Animal Viewer

Web

Medium

135 solves

minaminao

Bashrunner

Misc

Hard

114 solves

yu212

Paca Paca Authenticator

Crypto

Medium

116 solves

tchen

Stateless Auth

Web

Medium

149 solves

keymoon

git gc

Misc

Medium

139 solves

chocorusk

ToyPQC

Crypto

Hard

100 solves

tchen

No JS

Web

Medium

116 solves

k0080

shellcode-101

Pwn

Medium

117 solves

yu212

Linear Coffee Generator

Crypto

Hard

105 solves

ark

optimal-sort

Misc

Hard

94 solves

admin

Camelidae

Misc

Welcome

270 solves

Go to B-SIDE

Writeups

Writeup for Alpaillier goroshirow ja Alpaillier 5 hours ago
Writeup for simple ROP goroshirow ja simple ROP yesterday
Writeup for simple ROP rsk0315 ja simple ROP yesterday
Writeup for shellcode-101 rsk0315 ja shellcode-101 yesterday
Writeup for Daily AlpacaHack 2/8-2/14 kakur41 ja AAAAAAAAEEEEEEEESSSSSSSS +6 2 days ago
【脆弱】Daily AlpacaHackを作問者の前で解いてみた！ I wanna be the Admin【t-chen】 asusn ja I wanna be the Admin 2 days ago
Writeup for nc magic goroshirow ja nc magic 3 days ago
Writeup for AAAAAAAAEEEEEEEESSSSSSSS goroshirow ja AAAAAAAAEEEEEEEESSSSSSSS 4 days ago
Writeup for destructuring rsk0315 ja destructuring 4 days ago
Writeup for destructuring itsuki-t ja destructuring 4 days ago

Rows:

RRe_Time_Limiter

Topic: Number Theory

144 solves

Crypto

Medium

Author:

kanon

Waiting for "love" amid these monotonous days, only to end up declaring, "Life's boring after all!" by ...

rre-time-limiter.tar.gz

description solves writeups