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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!

Join Anytime

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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Sharing solutions is allowed only after 24 hours have passed since release.

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

SOLVED!

Jun 19, 10:27 AM

cat22222

SOLVED!

Jun 19, 9:59 AM

trimscash

SOLVED!

Jun 19, 9:03 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🌱
186 solves
3
minaminaominaminao
vm1
Misc
Medium
92 solves
4
pppp4649pppp4649
Small e
Crypto
Easy🌱
128 solves
5
minaminaominaminao
RPS GAME
Misc
Crypto
Medium
95 solves
6
nozokare
Flag for localhost
Web
Easy🌱
147 solves
7
tan90909090tan90909090
C++ flag checker
Rev
Hard
81 solves
8
shiragishiragi
Guess IP
Misc
Easy🌱
133 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
45 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

1 hour 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:

Stateless Auth

Topic: JWTReleased: Jan 25, 2026

180 solves
Web
Medium

by

tchen

tchen

Writeups

tchen

Author's Writeup for Stateless Auth

tchen

author
en

2026/01/28 16:20




kakur41

Writeup for Stateless Auth

ja

2026/01/25 15:16


kudaliar

Writeup for Stateless Auth

en

2026/01/27 15:32

descriptionsolveswriteups