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.

Solve stats

/161

No solved challenges yet.

Today's Challenge

Submissions (latest 3)

cyanos

SOLVED!

May 9, 6:15 PM

nomeaning

SOLVED!

May 9, 5:39 PM

tadanobutubutu

SOLVED!

May 9, 5:32 PM

Leaderboard

Period

Try the first challenge

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

Upcoming challenges reveal the , , and in advance.

Dec 2025

Solved

Unsolved

Upcoming

Mon

Tue

Wed

Thu

Fri

Sat

Sun

admin

AlpacaHack 2100

Misc

Welcome

1,761 solves

xornet

a fact of CTF

Crypto

Easy

934 solves

ark

Emojify

Web

Medium

623 solves

minaminao

Leaked Flag Checker

Rev

Easy

606 solves

mora

Integer Writer

Pwn

Hard

342 solves

n01e0

simpleoverflow

Pwn

Easy

542 solves

jp3bgy

size limit

Crypto

Medium

337 solves

yu212

Fully Padded RSA

Crypto

Hard

245 solves

ark

hit-and-miss

Misc

Easy

409 solves

xrekkusu

Read Assembly

Rev

Medium

331 solves

hiikunz

Alpaca Bank

Web

Medium

349 solves

chocorusk

Sugoi Flag Checker

Rev

Hard

216 solves

ptr-yudai

Safe Prime

Crypto

Medium

268 solves

iwashiira

power_obfus_royalty

Rev

Medium

222 solves

hiikunz

Flag Printer 2100

Rev

Medium

260 solves

ark

🐈

Web

Medium

323 solves

ptr-yudai

Pwn

Medium

268 solves

kanon

Twilight

Rev

Medium

239 solves

k0080

alloc-101

Pwn

Hard

226 solves

fabon

omikuji

Web

Medium

258 solves

RSA debug?

Crypto

Medium

200 solves

tchen

Log Viewer

Web

Medium

232 solves

hiikunz

Rotten Beef

Pwn

Medium

210 solves

minaminao

cat3

Misc

Medium

226 solves

hiikunz

Xmas Login

Web

Easy

373 solves

tchen

Useful Machine

Rev

Hard

165 solves

n01e0

simpleoverwrite

Pwn

Medium

204 solves

hi120ki

cha-ll-enge

Rev

Medium

164 solves

kanon

one-p-rsa

Crypto

Easy

247 solves

soon-haari

RBG

Crypto

Very Hard

126 solves

admin

108

Misc

Easy

306 solves

admin

Happy New Year

Misc

Welcome

583 solves

kanon

super-tomato

Crypto

Easy

406 solves

hiikunz

Ruby Flag Checker

Rev

Easy

301 solves

minaminao

Fushigi Crawler

Web

Easy

367 solves

Want a harder challenge?

Go to B-SIDE

Writeups

Writeup for reused n tadanobutubutu ja reused n 2 hours ago
Writeup for reused n baumroll1234 ja reused n 3 hours ago
Writeup for Daily AlpacaHack 5/3-5/9 kakur41 ja reused n +6 3 hours ago
Writeup for reused n goroshirow ja reused n 4 hours ago
Writeup for Vending Machine baumroll1234 author ja Vending Machine 6 hours ago
Writeup for Vending Machine tadanobutubutu ja Vending Machine 8 hours ago
Daily AlpacaHackに挑戦するつくよみちゃん 05/08 misc/Vending Machine/baumroll1234 tsukuyomi-chan ja Vending Machine 10 hours ago
Daily AlpacaHackに挑戦するつくよみちゃん 05/07 misc/Permission Denied 3/minaminao tsukuyomi-chan ja permission denied 3 10 hours ago
Writeup for Vending Machine nozokare ja Vending Machine 11 hours ago
Writeup for permission denied 3 nozokare ja permission denied 3 11 hours ago

Rows:

crypto_666

Topic: PrimeReleased: Mar 25, 2026

108 solves

Crypto

Medium

kurenaif

USER	SOLVED AT
sp1n0z4	last week
kurenaif	2 weeks ago
muhammed	2 weeks ago
paper	4 weeks ago
yu212	last month
poterin112	last month
novemura	last month
youle	last month
urneighbor1	last month
yoshykai	last month
haihuiliyuyuan	last month
nuhe	last month
elure	last month
8448	last month
tab4	last month
hgfbrz	last month
reyon	last month
n0v4	last month
saranrappu0831	last month
ctf-udon	last month
thayato	last month
chocorusk	last month
tet3	last month
pekyh	last month
alice-terui	last month