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Daily AlpacaHack

A CTF challenge series with fun puzzles to enjoy every day

What is Daily AlpacaHack?

We regularly publish simple, beginner-friendly or educational CTF challenges!

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

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

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Today's Challenge
hiikunzhiikunz
decreasing
Misc
Hard
18 solves
Submissions (latest 3)
serioton
serioton

SOLVED!

Oct 15, 10:13 PM

pppp4649

SOLVED!

Oct 15, 2:25 PM

Leaderboard

Try the first challenge

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

View challenge
admin
AlpacaHack 2100
Misc
Welcome🌱
2,286 solves
Upcoming challenges reveal the , , and in advance.
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Oct 2026

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k0080k0080
what is my pointer 2
Pwn
Hard
46 solves
1
admin
Baby Alpaca
Misc
Welcome🌱
137 solves
2
tan90909090tan90909090
C# File-based app
Rev
Easy🌱
72 solves
3-4
2501
Shared Prime
Crypto
Medium
77 solves
5-8
tan90909090tan90909090
fsbase modification
Pwn
Hard
58 solves
9-12
2501
Almost Shared Prime
Crypto
Hard
42 solves
 
2501
Almost Shared Prime
Crypto
Hard
42 solves
13-14
tan90909090tan90909090
cowsay jail
Misc
Medium
55 solves
15-18
hiikunzhiikunz
decreasing
Misc
Hard
18 solves
19
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Writeups

ojun

Writeup for fsbase modification

ojun

ja
fsbase modification

11 hours ago

tadanobutubutu

Writeup for cowsay jail

tadanobutubutu

Writeup for Almost Shared Prime

nirvana

Writeup for cowsay jail

ja

2026/10/14 21:19

Rows:

Let's Poly1305!

Topic: MACReleased: Jul 8, 2026

88 solves
Crypto
Medium5.0

by

minaminao

minaminao

Writeups

Writeup for Let's Poly1305!

goroshirow

ja

2026/07/08 17:07



Daily AlpacaHackに挑戦するつくよみちゃん07/08/Let's Poly1305!/minaminao

ja

2026/07/08 15:59


kurimochi

Writeup for Let's Poly1305!

ja

2026/07/10 13:13

descriptionsolveswriteups