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!

Join Anytime

Solve each challenge within its time window 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 the challenge period has ended.

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Today's Challenge

tan90909090

sin function vs. fsin instruction

Submissions (latest 3)

nuskey8

SOLVED!

Sep 12, 1:17 PM

chara0x

SOLVED!

Sep 12, 12:04 PM

bhcnumas

SOLVED!

Sep 12, 11:11 AM

Leaderboard

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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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Sep 2026

Solved

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Mon

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Sun

tchen

Springing

Web

Medium

69 solves

admin

QUIZ ALPACASHOCK

Misc

Welcome🌱

111 solves

hiikunz

base 16-32-64

Misc

Easy🌱

87 solves

3-4

tan90909090

Let's Shut Down Linux

Misc

Medium

55 solves

baumroll1234

Vending Machine: Revised Version

Misc

Easy🌱

73 solves

6-8

minaminao

Bitflip RSA

Crypto

Hard

47 solves

minaminao

Bitflip RSA

Crypto

Hard

47 solves

9-11

minaminao

＼^o^／

Misc

Hard

34 solves

12-13

tan90909090

sin function vs. fsin instruction

Rev

Misc

Medium

29 solves

Coming soon

Want a harder challenge?

Go to B-SIDE

Writeups

Writeup for Leaked Flag Checker

gattoartz

Leaked Flag Checker

2026/09/07 13:39

Writeup for a fact of CTF

gattoartz

a fact of CTF

2026/09/07 13:08

Writeup for AlpacaHack 2100

gattoartz

AlpacaHack 2100

2026/09/07 13:07

Writeup for Vending Machine: Revised Version

baumroll1234

author

Vending Machine: Revised Version

2026/09/06 15:02

Writeup for Vending Machine: Revised Version (warn: some code reading ahead)

nitcelcius

Vending Machine: Revised Version

2026/09/06 05:59

Writeup for Let's Shut Down Linux (with reading)

nitcelcius

Let's Shut Down Linux

2026/09/05 05:49

Writeup for Springing

curetwinkle

Springing

2026/09/05 05:10

Writeup for Let's Shut Down Linux

mizore-fuyu

Let's Shut Down Linux

2026/09/05 02:40

Writeup for Let's Shut Down Linux

baumroll1234

Let's Shut Down Linux

2026/09/05 00:33

Writeup for Let's Shut Down Linux

lumma

Let's Shut Down Linux

2026/09/04 23:05

Rows:

✌️✌️✌️

Topic: Secret SharingReleased: Jun 22, 2026

122 solves

Crypto

Easy🌱3.0

minaminao