AlpacaHack Logo
Sign InSign Up
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

0

/22

No solved challenges yet.

Sign In to view your player stats

Today's Challenge
minaminaominaminao
✌️✌️✌️
Crypto
Easy🌱
21 solves
Submissions (latest 3)
tenagazaru

SOLVED!

Jun 21, 5:58 PM

tko919

SOLVED!

Jun 21, 5:39 PM

bhcnumas

SOLVED!

Jun 21, 5:18 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🌱
1,903 solves
Upcoming challenges reveal the , , and in advance.
Prev

Jun 2026

Next
Solved
Unsolved
Upcoming
Mon
Tue
Wed
Thu
Fri
Sat
Sun
1
admin
Half-Year Recap
Misc
Welcome🌱
230 solves
2
minaminaominaminao
Cache Me If You Can
Web
Easy🌱
193 solves
3
minaminaominaminao
vm1
Misc
Medium
93 solves
4
pppp4649pppp4649
Small e
Crypto
Easy🌱
132 solves
5
minaminaominaminao
RPS GAME
Misc
Crypto
Medium
96 solves
6
nozokare
Flag for localhost
Web
Easy🌱
153 solves
7
tan90909090tan90909090
C++ flag checker
Rev
Hard
84 solves
8
shiragishiragi
Guess IP
Misc
Easy🌱
137 solves
9
nozokare
A Piece of DHKE
Crypto
Medium
81 solves
10
shiragishiragi
chmod-swapper
Misc
Medium
82 solves
11
tchentchen
Alpaca Certification
Web
Easy🌱
149 solves
12
rsk0315
Floating Equality
Misc
Medium
89 solves
13
pppp4649pppp4649
Elliptic Equation
Crypto
Hard
58 solves
14
tchentchen
CAuth
Web
Hard
65 solves
15
minaminaominaminao
SITE/2
Web
Easy🌱
115 solves
16
tan90909090tan90909090
Xored PNG
Misc
Medium
84 solves
17
tchentchen
Looks like Alpacahack
Web
Medium
80 solves
18
shiragishiragi
Catrunner 2
Misc
Easy🌱
100 solves
19
minaminaominaminao
Flag Printer 20XX
Misc
Medium
60 solves
20
nozokare
xorshift521
Crypto
Hard
53 solves
21
k0080k0080
what-is-my-size
Pwn
Hard
58 solves
22
minaminaominaminao
✌️✌️✌️
Crypto
Easy🌱
21 solves
23
tchentchen
Planned topicNginx
Web
Medium
24
kanonkanon
Planned topicBlock Cipher
Crypto
Medium
25
colza
Planned topicArchive
Misc
Easy🌱
26
Coming soon
27
bubu
Planned topicClient-Side
Web
Hard
28
pppp4649pppp4649
Planned topicTBA
Pwn
Hard
29
Coming soon
30
Coming soon
1
admin
Planned topicWelcome
Misc
Welcome🌱
2
hiikunzhiikunz
Planned topicMathematics
Crypto
Easy🌱
3
Coming soon
4
Coming soon
5
Coming soon

Want a harder challenge?

Go to B-SIDE

Writeups

Writeup for what-is-my-size

goroshirow

ja
what-is-my-size

2 hours ago

Writeup for xorshift521

umineko

ja
xorshift521

13 hours ago

Daily AlpacaHackに挑戦するつくよみちゃん 06/20/xorshift521/nozokare

tsukuyomi-chan

ja
xorshift521

2026/06/20 15:40

Writeup for xorshift521

baumroll1234

ja
xorshift521

2026/06/20 15:22

Writeup for xorshift521

goroshirow

ja
xorshift521

2026/06/20 15:21

Daily AlpacaHackに挑戦するつくよみちゃん 06/19/Flag Printer 20XX/minaminao

tsukuyomi-chan

ja
Flag Printer 20XX

2026/06/20 15:12

Writeup for Flag Printer 20XX

baumroll1234

ja
Flag Printer 20XX

2026/06/19 16:02

Writeup for Flag Printer 20XX

goroshirow

ja
Flag Printer 20XX

2026/06/19 15:20

nirvana

Writeup for Catrunner 2

nirvana

ja
Catrunner 2

2026/06/19 08:56

Daily AlpacaHackに挑戦するつくよみちゃん 06/18/Catrunner 2/shiragi

tsukuyomi-chan

ja
Catrunner 2

2026/06/18 15:02

Rows:

✌️✌️✌️

Topic: Secret SharingReleased: Jun 22, 2026

21 solves
Crypto
Easy🌱

by

minaminao

minaminao

Be kind to people

Beginner Hint 1
  • This is a simple Shamir's Secret Sharing.
  • The unknowns are c0 (= flag), c1, and c2.
Beginner Hint 2
  • This is a system of linear equations with three equations for three unknowns.

(automatically translated from Japanese)

3-pieces.tar.gz

Please sign in to submit the flag.

descriptionsolves