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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!

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Solve each challenge within its time window to appear on the leaderboard.

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Discussion with friends or AI is welcome (account sharing is prohibited).

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Sharing solutions is allowed only after the challenge period has ended.

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Today's Challenge
pppp4649pppp4649
Σecret
Crypto
Easy🌱
14 solves
Submissions (latest 3)
hiroyuki

SOLVED!

Oct 22, 11:54 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🌱
2,300 solves
Upcoming challenges reveal the , , and in advance.
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Oct 2026

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k0080k0080
what is my pointer 2
Pwn
Hard
47 solves
1
admin
Baby Alpaca
Misc
Welcome🌱
154 solves
2
tan90909090tan90909090
C# File-based app
Rev
Easy🌱
76 solves
3-4
2501
Shared Prime
Crypto
Medium
86 solves
5-8
tan90909090tan90909090
fsbase modification
Pwn
Hard
59 solves
9-12
2501
Almost Shared Prime
Crypto
Hard
44 solves
 
2501
Almost Shared Prime
Crypto
Hard
44 solves
13-14
tan90909090tan90909090
cowsay jail
Misc
Medium
59 solves
15-18
hiikunzhiikunz
decreasing
Misc
Hard
34 solves
19-22
tan90909090tan90909090
x32 ABI flag checker
Rev
Hard
29 solves
23-24
pppp4649pppp4649
Σecret
Crypto
Easy🌱
14 solves
25
Coming soon
26
Coming soon
27
Coming soon
28
Coming soon
29
Coming soon
30
Coming soon
31
Coming soon
1
Coming soon

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Writeups

Writeup for Mirage

haruhana

ja
Mirage

21 hours ago

ojun

Writeup for fsbase modification

ja

2026/10/15 13:59

tadanobutubutu

Writeup for cowsay jail

ja

2026/10/15 08:42

tadanobutubutu

Writeup for Almost Shared Prime

nirvana

Writeup for cowsay jail

ja

2026/10/14 21:19

Rows:

Shared Prime

Topic: RSAReleased: Oct 3, 2026

86 solves
Crypto
Medium3.5

by

2501

USER

SOLVED AT

andante1666

16 hours ago

18 hours ago

21 hours ago

2026/10/21 03:08

2026/10/20 10:16

2026/10/19 23:43

2026/10/19 20:05

2026/10/18 08:14

2026/10/16 09:49

2026/10/15 10:38

2026/10/15 08:11

2026/10/13 10:34

2026/10/13 08:51

2026/10/13 08:38

2026/10/13 06:14

2026/10/13 04:55

2026/10/12 19:55

2026/10/12 15:40

2026/10/12 08:30

2026/10/12 07:25

2026/10/11 13:07

2026/10/11 07:19

2026/10/10 20:19

2026/10/10 19:05

2026/10/10 14:04

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