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

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Today's Challenge
minaminaominaminao
Flag Printer 20XX
Misc
Medium
43 solves
Submissions (latest 3)
trimscash
trimscash

SOLVED!

Jun 19, 9:03 AM

ahnmo

SOLVED!

Jun 19, 8:46 AM

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🌱
1,896 solves
Upcoming challenges reveal the , , and in advance.
Prev

Jun 2026

Next
Solved
Unsolved
Upcoming
Mon
Tue
Wed
Thu
Fri
Sat
Sun
1
admin
Half-Year Recap
Misc
Welcome🌱
222 solves
2
minaminaominaminao
Cache Me If You Can
Web
Easy🌱
185 solves
3
minaminaominaminao
vm1
Misc
Medium
92 solves
4
pppp4649pppp4649
Small e
Crypto
Easy🌱
127 solves
5
minaminaominaminao
RPS GAME
Misc
Crypto
Medium
95 solves
6
nozokare
Flag for localhost
Web
Easy🌱
146 solves
7
tan90909090tan90909090
C++ flag checker
Rev
Hard
81 solves
8
shiragishiragi
Guess IP
Misc
Easy🌱
132 solves
9
nozokare
A Piece of DHKE
Crypto
Medium
80 solves
10
shiragishiragi
chmod-swapper
Misc
Medium
80 solves
11
tchentchen
Alpaca Certification
Web
Easy🌱
146 solves
12
rsk0315
Floating Equality
Misc
Medium
89 solves
13
pppp4649pppp4649
Elliptic Equation
Crypto
Hard
57 solves
14
tchentchen
CAuth
Web
Hard
61 solves
15
minaminaominaminao
SITE/2
Web
Easy🌱
110 solves
16
tan90909090tan90909090
Xored PNG
Misc
Medium
83 solves
17
tchentchen
Looks like Alpacahack
Web
Medium
74 solves
18
shiragishiragi
Catrunner 2
Misc
Easy🌱
89 solves
19
minaminaominaminao
Flag Printer 20XX
Misc
Medium
43 solves
20
nozokare
Planned topicRNG
Crypto
Hard
21
Planned topicHeap
Pwn
Hard
22
Planned topicSecret Sharing
Crypto
Easy🌱
23
Planned topicNginx
Web
Medium
24
Coming soon
26
Coming soon
28
Planned topicTBA
Pwn
Hard
29
Coming soon
30
Coming soon
2
Coming soon
3
Coming soon
4
Coming soon
5
Coming soon

Want a harder challenge?

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Writeups

nirvana

Writeup for Catrunner 2

nirvana

ja
Catrunner 2

29 minutes ago

Daily AlpacaHackに挑戦するつくよみちゃん 06/18/Catrunner 2/shiragi

nirvana

Writeup for Looks like Alpacahack

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

tadanobutubutu

Writeup for Xored PNG

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

ja

2026/06/16 17:06

tadanobutubutu

Writeup for SITE/2

ja

2026/06/16 10:33

Rows:

fake-shuffle-proof

Topic: Broken CommitmentReleased: Apr 20, 2026

121 solves
Crypto
Easy🌱

by

shiro

USER

SOLVED AT

nyaru

2026/06/17 07:27

2026/06/02 11:34

2026/05/21 04:41

2026/05/14 02:12

2026/05/05 02:29

2026/05/04 15:34

2026/05/04 15:26

2026/05/03 22:48

2026/05/03 09:25

2026/04/30 07:17

2026/04/29 21:45

2026/04/29 06:36

2026/04/27 15:38

2026/04/27 12:20

2026/04/27 06:38

2026/04/26 08:12

2026/04/26 05:28

2026/04/25 18:21

2026/04/25 06:30

2026/04/24 20:45

2026/04/24 08:34

2026/04/23 14:05

2026/04/23 13:49

2026/04/23 02:49

2026/04/23 02:36

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descriptionsolveswriteups