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!

Join Anytime

Solve each challenge within its time window 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 the challenge period has ended.

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No solved challenges yet.

Today's Challenge

Submissions (latest 3)

kurokane-isumi

SOLVED!

Aug 25, 12:36 PM

bubu

SOLVED!

Aug 25, 9:26 AM

bpaul

SOLVED!

Aug 25, 9:15 AM

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.

Aug 2026

Solved

Unsolved

Upcoming

Mon

Tue

Wed

Thu

Fri

Sat

Sun

tchen

RFC100008

Web

Easy🌱

142 solves

2501

One More Approval

Crypto

Medium

61 solves

2501

zen.zip

Misc

Medium

68 solves

2501

Anyrunner

Misc

Medium

65 solves

tchen

Small Image Uploader 2

Web

Medium

61 solves

admin

Día Nacional de la Alpaca

Misc

Welcome🌱

222 solves

2501

Password, Please

Misc

Easy🌱

190 solves

3-4

ark

Long Long Flag Printer 2026

Misc

Medium

93 solves

pppp4649

Happy Birthday

Crypto

Easy🌱

121 solves

6-8

hiikunz

AESAESAESAESAESAES

Crypto

Hard

59 solves

9-10

tchen

Not so Pyf**k

Misc

Medium

82 solves

tchen

Not so Pyf**k

Misc

Medium

82 solves

11-12

baumroll1234

Fermat's Last Theorem

Misc

Medium

80 solves

13-15

tchen

True or False 2

Misc

Hard

52 solves

16-17

tchen

List Sharing

Web

Medium

71 solves

tchen

List Sharing

Web

Medium

71 solves

18-20

tan90909090

wrong instruction

Rev

Hard

57 solves

21-23

tchen

Greetings i18n 2

Web

Hard

49 solves

24-26

tchen

Xwitter

Web

Hard

26 solves

Coming soon

Want a harder challenge?

Go to B-SIDE

Writeups

Writeup for wrong instruction

umineko

wrong instruction

2026/08/22 05:08

Writeup for You are my friend

haruhana

You are my friend

2026/08/21 02:40

Writeup for wrong instruction

baumroll1234

wrong instruction

2026/08/20 21:20

Writeup for Plz Login

haruhana

Plz Login

2026/08/20 03:21

Writeup for Leaked Flag Checker

power

Leaked Flag Checker

2026/08/18 11:53

Writeup for Password, Please

power

Password, Please

2026/08/18 03:26

Writeup for List Sharing

baumroll1234

List Sharing

2026/08/17 20:44

Writeup for Ruby Flag Checker

haruhana

Ruby Flag Checker

2026/08/16 03:34

Writeup for True or False 2

baumroll1234

True or False 2

2026/08/16 00:09

Writeup for True or False 2

rsk0315

True or False 2

2026/08/15 15:03

Rows:

A Piece of DHKE

Topic: Diffie–HellmanReleased: Jun 9, 2026

86 solves

Crypto

Medium6.0

nozokare

USER	SOLVED AT
tmatsuura	2026/07/10 09:19
nakamulab	2026/06/30 01:09
goat-antony2008	2026/06/29 09:29
kuroiko	2026/06/27 12:38
tkfire4869nd	2026/06/25 08:28
ly4	2026/06/20 10:58
n-and-n3	2026/06/17 05:51
shoki	2026/06/17 02:32
sp1n0z4	2026/06/16 15:25
despair09	2026/06/12 13:37
id1112	2026/06/12 12:25
tyage	2026/06/11 13:41
serioton	2026/06/11 12:13
kapumoka	2026/06/10 18:27
cqbtq	2026/06/10 16:48
kyoro	2026/06/10 11:09
barleytea	2026/06/10 08:51
umachaba	2026/06/10 07:03
tsukuyomi-chan	2026/06/09 16:15
ntanaka	2026/06/09 15:40
iliss-557	2026/06/09 15:24
kakur41	2026/06/09 15:00
redpo	2026/06/09 14:37
nozokare	2026/06/09 14:25
kitatai	2026/06/09 14:25