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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!

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Solve within 24 hours of release to appear on the leaderboard.

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Today's Challenge

Compile time flag checker

Submissions (latest 3)

SOLVED!

Jul 11, 4:36 PM

SOLVED!

Jul 11, 4:34 PM

SOLVED!

Jul 11, 4:08 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.

Jul 2026

Solved

Unsolved

Upcoming

Mon

Tue

Wed

Thu

Fri

Sat

Sun

29

tchen

Web

Medium

80 solves

30

minaminao

Super Short System Exit

Misc

Medium

79 solves

1

admin

Misc

Welcome🌱

182 solves

2

hiikunz

Crypto

Easy🌱

117 solves

3

tchen

Web

Easy🌱

108 solves

4

hiikunz

Rev

Medium

96 solves

5

tchen

IP Blocked Secret

Web

Hard

59 solves

6

minaminao

duplicate entry

Misc

Easy🌱

113 solves

7

hiikunz

Crypto

Medium

94 solves

8

minaminao

Let's Poly1305!

Crypto

Medium

72 solves

9

shiragi

Misc

Easy🌱

101 solves

10

hiikunz

Web

Medium

73 solves

11

baumroll1234

A slight mistake

Pwn

Hard

53 solves

12

tan90909090

Compile time flag checker

Rev

Hard

14 solves

13

Planned topicHTTP

Web

Easy🌱

14

Planned topicJail

Misc

Medium

15

Coming soon

16

Coming soon

17

Planned topicMAC

Crypto

Medium

18

Planned topicCGI

Web

Hard

19

Planned topicStack

Pwn

Hard

20

Coming soon

21

Coming soon

22

Planned topicCache

Web

Medium

23

Coming soon

24

Coming soon

25

Planned topicMAC

Crypto

Hard

26

Planned topicPython

Web

Hard

27

Coming soon

28

Coming soon

29

Coming soon

30

Coming soon

31

Coming soon

1

Planned topicWelcome

Misc

Welcome🌱

2

Coming soon

Want a harder challenge?

Writeups

Writeup for A slight mistake

goroshirow

ja

A slight mistake

2 hours ago

Writeup for secret-table-3

baumroll1234

ja

16 hours ago

Writeup for Let's Poly1305!

kurimochi

ja

Let's Poly1305!

2026/07/10 13:13

Writeup for private method

nitcelcius

ja

2026/07/10 09:37

Writeup for Find XOR key

haruhana

ja

2026/07/10 02:48

Writeup for private method

nirvana

ja

2026/07/09 22:52

Writeup for private method

baumroll1234

ja

2026/07/09 16:53

Writeup for Let's Poly1305!

baumroll1234

ja

Let's Poly1305!

2026/07/08 20:20

Writeup for Let's Poly1305!

goroshirow

ja

Let's Poly1305!

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

tsukuyomi-chan

ja

Let's Poly1305!

2026/07/08 15:59

Rows:

Compile time flag checker

Topic: C++Released: Jul 12, 2026

14 solves

Hard

by

tan90909090

USER	SOLVED AT
cat22222	48 minutes ago
pppp4649	50 minutes ago
kurgm	1 hour ago
itsuki-t	1 hour ago
a01sa01to	1 hour ago
rsk0315	1 hour ago
hiikunz	1 hour ago
kurokane-isumi	1 hour ago
mti	2 hours ago
syn9	2 hours ago
nuhe	2 hours ago
nanashiku	2 hours ago
mak0tan	2 hours ago
umineko	2 hours ago

Rows:

description solves