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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)

SOLVED!

Jun 18, 2:23 PM

SOLVED!

Jun 18, 2:21 PM

SOLVED!

Jun 18, 2:20 PM

Leaderboard

Period

Try the first challenge

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

AlpacaHack 2100

Upcoming challenges reveal the , , and in advance.

Jun 2026

Solved

Unsolved

Upcoming

Mon

Tue

Wed

Thu

Fri

Sat

Sun

1

admin

Half-Year Recap

Misc

Welcome🌱

222 solves

2

minaminao

Cache Me If You Can

Web

Easy🌱

183 solves

3

minaminao

Misc

Medium

92 solves

4

pppp4649

Crypto

Easy🌱

125 solves

5

minaminao

Misc

Crypto

Medium

93 solves

6

nozokare

Flag for localhost

Web

Easy🌱

146 solves

7

tan90909090

C++ flag checker

Rev

Hard

80 solves

8

shiragi

Misc

Easy🌱

130 solves

9

nozokare

A Piece of DHKE

Crypto

Medium

80 solves

10

shiragi

Misc

Medium

79 solves

11

tchen

Alpaca Certification

Web

Easy🌱

144 solves

12

rsk0315

Floating Equality

Misc

Medium

89 solves

13

pppp4649

Elliptic Equation

Crypto

Hard

56 solves

14

tchen

Web

Hard

61 solves

15

minaminao

Web

Easy🌱

109 solves

16

tan90909090

Misc

Medium

81 solves

17

tchen

Looks like Alpacahack

Web

Medium

70 solves

18

shiragi

Misc

Easy🌱

78 solves

19

Planned topicPython

Misc

Medium

20

Planned topicRNG

Crypto

Hard

21

Planned topicHeap

Pwn

Hard

22

Planned topicSecret Sharing

Crypto

Easy🌱

23

Planned topicNginx

Web

Medium

24

Coming soon

25

Planned topicArchive

Misc

Easy🌱

26

Coming soon

27

Planned topicClient-Side

Web

Hard

28

Planned topicTBA

Pwn

Hard

29

Coming soon

30

Coming soon

1

Planned topicWelcome

Misc

Welcome🌱

2

Coming soon

3

Coming soon

4

Coming soon

5

Coming soon

Want a harder challenge?

Writeups

Writeup for Looks like Alpacahack

nirvana

ja

Looks like Alpacahack

13 hours ago

Daily AlpacaHackに挑戦するつくよみちゃん 06/17/Looks like Alpacahack/tchen

tsukuyomi-chan

ja

Looks like Alpacahack

21 hours ago

Writeup for Looks like Alpacahack

baumroll1234

ja

Looks like Alpacahack

22 hours ago

Writeup for Looks like Alpacahack

goroshirow

ja

Looks like Alpacahack

23 hours ago

Writeup for Xored PNG

baumroll1234

ja

2026/06/16 20:22

Writeup for Xored PNG

tadanobutubutu

ja

2026/06/16 17:17

Daily AlpacaHackに挑戦するつくよみちゃん 06/16/Xored PNG/tan90909090

tsukuyomi-chan

ja

2026/06/16 17:06

Writeup for SITE/2

tadanobutubutu

ja

2026/06/16 10:33

Writeup for SITE/2

nirvana

ja

2026/06/15 21:55

Writeup for SITE/2

baumroll1234

ja

2026/06/15 16:43

Rows:

Read Assembly

Topic: AssemblyReleased: Dec 10, 2025

345 solves

Medium

by

xrekkusu

Tags

Writeups

Writeup for Read Assembly

lluuiiggee

ja

2025/12/11 16:19

Writeup for Read Assembly (Gist and no explanation)

xornet

en

2025/12/11 16:23

Writeup for Read Assembly

neglect-yp

ja

2025/12/14 15:09

Daily AlpacaHack 2週間目Writeup 12/08~12/14

trimscash

ja

2025/12/15 19:49

Daily AlpacaHack Week 2 (2025-12-08 〜 2025-12-14)

n0name

ja

2025/12/21 12:43

Writeup for Daily Challenge (2025/12/8~2025/12/14)

labpump

ja

2025/12/30 13:41

description solves writeups