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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
kanonkanon
honk the klaxon
Crypto
Medium
34 solves
Submissions (latest 3)
pppp4649
pppp4649

SOLVED!

Jun 24, 5:08 AM

Leaderboard

Try the first challenge

Is this your first CTF? Let's begin by tackling the first challenge released on Daily AlpacaHack.

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admin
AlpacaHack 2100
Misc
Welcome🌱
1,909 solves
Upcoming challenges reveal the , , and in advance.
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Jun 2026

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1
admin
Half-Year Recap
Misc
Welcome🌱
237 solves
2
minaminaominaminao
Cache Me If You Can
Web
Easy🌱
199 solves
3
minaminaominaminao
vm1
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4
pppp4649pppp4649
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minaminaominaminao
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96 solves
6
nozokare
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7
tan90909090tan90909090
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9
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10
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tchentchen
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rsk0315
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13
pppp4649pppp4649
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59 solves
14
tchentchen
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65 solves
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minaminaominaminao
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117 solves
16
tan90909090tan90909090
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tchentchen
Looks like Alpacahack
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80 solves
18
shiragishiragi
Catrunner 2
Misc
Easy🌱
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minaminaominaminao
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Misc
Medium
61 solves
20
nozokare
xorshift521
Crypto
Hard
54 solves
21
k0080k0080
what-is-my-size
Pwn
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63 solves
22
minaminaominaminao
✌️✌️✌️
Crypto
Easy🌱
84 solves
23
tchentchen
Secret Renderer
Web
Medium
69 solves
24
kanonkanon
honk the klaxon
Crypto
Medium
34 solves
25
colza
Planned topicArchive
Misc
Easy🌱
26
Coming soon
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Planned topicTBA
Pwn
Hard
29
Coming soon
30
Coming soon
2
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Crypto
Easy🌱
3
Coming soon
4
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Writeups

Daily AlpacaHackに挑戦するつくよみちゃん 06/23/Secret Renderer/tchen

tsukuyomi-chan

ja
Secret Renderer

13 hours ago

minaminao

Writeup for ✌️✌️✌️

author
ja

2026/06/22 17:14

Daily AlpacaHackに挑戦するつくよみちゃん 06/22/✌️✌️✌️/minaminao

tadanobutubutu

Writeup for ✌️✌️✌️

tadanobutubutu

Writeup for what-is-my-size

Daily AlpacaHackに挑戦するつくよみちゃん 06/20/xorshift521/nozokare

ja

2026/06/20 15:40

Rows:

RBG

Topic: RSA, LCGReleased: Dec 30, 2025

132 solves
Crypto
Very Hard6.0

by

soon-haari

soon-haari

RBG stands for RSA + SBG + LCG!
To learn about them, please check out lecture1.mp4.

Beginner Hint: Very Hard (AI-translated)
  • This challenge's difficulty is Very Hard.
  • Very Hard is assigned to challenges that require substantial reasoning and are difficult to solve by simply applying standard techniques directly.
  • This challenge is one of them. It is an interesting challenge that requires some insight, so please give it a try.
  • For beginners, solving it entirely on your own will be difficult. If you get stuck, we recommend making good use of AI as needed, deepening your understanding little by little, and looking for a starting point for the solution.
rbg.tar.gz

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