Sign In Sign 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

/23

No solved challenges yet.

Sign In to view your player stats

Today's Challenge

Submissions (latest 3)

SOLVED!

Jul 22, 4:37 PM

SOLVED!

Jul 22, 4:19 PM

SOLVED!

Jul 22, 4:18 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

88 solves

30

minaminao

Super Short System Exit

Misc

Medium

83 solves

1

admin

Misc

Welcome🌱

237 solves

2

hiikunz

Crypto

Easy🌱

142 solves

3

tchen

Web

Easy🌱

133 solves

4

hiikunz

Rev

Medium

108 solves

5

tchen

IP Blocked Secret

Web

Hard

65 solves

6

minaminao

duplicate entry

Misc

Easy🌱

138 solves

7

hiikunz

Crypto

Medium

102 solves

8

minaminao

Let's Poly1305!

Crypto

Medium

76 solves

9

shiragi

Misc

Easy🌱

133 solves

10

hiikunz

Web

Medium

84 solves

11

baumroll1234

A slight mistake

Pwn

Hard

69 solves

12

tan90909090

Compile time flag checker

Rev

Hard

56 solves

13

baumroll1234

Redirecting to Login Page

Web

Easy🌱

143 solves

14

tchen

You've Got Shlex

Misc

Medium

87 solves

15

minaminao

Let's Poly1305! 2

Crypto

Hard

64 solves

16

tchen

Beat the Alpaca Lord

Web

Medium

89 solves

17

pppp4649

Crypto

Medium

85 solves

18

tchen

Web

Hard

69 solves

19

hiikunz

Pwn

Hard

70 solves

20

tchen

Web

Easy🌱

106 solves

21

tan90909090

Rev

Misc

Medium

64 solves

22

ark

Misc

Hard

34 solves

23

tchen

Misc

Medium

15 solves

24

Coming soon

25

Planned topicCache

Web

Hard

26

Planned topicPython

Web

Hard

27

Planned topicHTTP

Web

Easy🌱

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 NOP Variant

umineko

ja

12 hours ago

Daily AlpacaHackに挑戦するつくよみちゃん07/21/NOP Variant/tan90909090

tsukuyomi-chan

ja

2026/07/21 16:33

Writeup for Alpaca Blog

nirvana

ja

2026/07/21 13:38

Writeup for Alpaca Blog

baumroll1234

ja

2026/07/20 21:53

Writeup for no win func

ojun

ja

2026/07/19 15:04

Writeup for You've Got Shlex (shlex only)

kurimochi

ja

You've Got Shlex

2026/07/19 05:58

Writeup for Greetings CGI

baumroll1234

ja

2026/07/18 23:23

Writeup for You've Got Shlex

nitcelcius

ja

You've Got Shlex

2026/07/18 12:59

Writeup for Compile time flag checker

edwowmath

ja

Compile time flag checker

2026/07/18 02:07

Writeup for biribiri

baumroll1234

ja

2026/07/17 21:38

Rows:

True or False

Topic: OracleReleased: Jul 23, 2026

15 solves

Medium

by

tchen

Everything comes in dualities: light and dark, day and night, true and false.

Beginner Hint

There is probably no way to leak the random value or the flag directly with eval.
In Python, True behaves almost like 1, and False behaves almost like 0. Use this fact wisely.
If you think you found a solution that only works with an extremely low probability, you are probably doing something wrong.

true-or-false.tar.gz

description solves