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)

xnmhuveb

SOLVED!

Feb 18, 12:15 AM

kowerkoint

SOLVED!

Feb 17, 11:56 PM

capypara

SOLVED!

Feb 17, 11:02 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.

Feb 2026

Solved

Unsolved

Upcoming

Mon

Tue

Wed

Thu

Fri

Sat

Sun

keymoon

git gc

Misc

Medium

139 solves

chocorusk

ToyPQC

Crypto

Hard

100 solves

tchen

No JS

Web

Medium

118 solves

k0080

shellcode-101

Pwn

Medium

117 solves

yu212

Linear Coffee Generator

Crypto

Hard

105 solves

ark

optimal-sort

Misc

Hard

95 solves

admin

Camelidae

Misc

Welcome

276 solves

minaminao

Substance

Crypto

Easy

188 solves

tan90909090

read-a-binary

Rev

Easy

172 solves

tchen

Magic Engine

Web

Easy

196 solves

kanon

RRe_Time_Limiter

Crypto

Medium

145 solves

minaminao

The World

Misc

Easy

147 solves

tan90909090

misdirection

Rev

Medium

123 solves

hiikunz

Compressor

Misc

Hard

93 solves

tchen

Plz Login

Web

Medium

163 solves

k0080

Alpaca-Llama Ranch

Pwn

Hard

103 solves

ark

destructuring

Misc

Easy

116 solves

hiikunz

AAAAAAAAEEEEEEEESSSSSSSS

Crypto

Medium

99 solves

minaminao

nc magic

Misc

Medium

109 solves

hiikunz

simple ROP

Pwn

Hard

88 solves

tchen

You are being redirected

Web

Medium

80 solves

kakur41

Alpaillier

Crypto

Medium

100 solves

rsk0315

wages of sin()

Rev

Misc

Hard

82 solves

k0080

Disappeared

Pwn

Medium

43 solves

minaminao

Planned topicDeserialization

Misc

Medium

rsk0315

Planned topicControl Sequences

Misc

Rev

Medium

pppp4649

Planned topicRSA

Crypto

Hard

k0080

Planned topicUninitialized Memory

Pwn

Hard

Coming soon

Go to B-SIDE

Writeups

Writeup for wages of sin() rsk0315 author ja wages of sin() 10 hours ago
Writeup for Daily AlpacaHack 1/26-2/1 labpump ja ToyPQC +5 11 hours ago
Writeup for Alpaillier baumroll1234 ja Alpaillier yesterday
Writeup for Alpaillier goroshirow ja Alpaillier yesterday
Writeup for simple ROP goroshirow ja simple ROP 2 days ago
Writeup for simple ROP rsk0315 ja simple ROP 3 days ago
Writeup for shellcode-101 rsk0315 ja shellcode-101 3 days ago
Writeup for Daily AlpacaHack 2/8-2/14 kakur41 ja AAAAAAAAEEEEEEEESSSSSSSS +6 3 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 3 days ago
Writeup for nc magic goroshirow ja nc magic 4 days ago

Rows:

Linear Coffee Generator

Topic: LCG

105 solves

Crypto

Hard

Author:

yu212

Let's take a break with coffee ☕

linear-coffee-generator.tar.gz

description solves writeups