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.

Not a Competition

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

Solution Sharing Rules

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

Solve stats

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No solved challenges yet.

Today's Challenge

Submissions (latest 3)

nirvana

SOLVED!

May 25, 10:45 AM

yimachi

SOLVED!

May 25, 10:42 AM

ss8888888

SOLVED!

May 25, 10:32 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.

Upcoming challenges reveal the , , and in advance.

May 2026

Solved

Unsolved

Upcoming

Mon

Tue

Wed

Thu

Fri

Sat

Sun

shiragi

Unrevealed TXT

Misc

Easy🌱

128 solves

serioton

unheard

Misc

Medium

77 solves

minaminao

permission denied

Misc

Hard

81 solves

minaminao

permission denied 2

Misc

Medium

82 solves

admin

Alpaca++

Misc

Welcome🌱

249 solves

tchen

Alpaca Rangers 2

Web

Easy🌱

209 solves

pppp4649

Small N

Crypto

Easy🌱

155 solves

hiikunz

secret-table-2

Web

Medium

145 solves

serioton

do the math

Misc

Medium

114 solves

trimscash

func-array

Pwn

Easy🌱

147 solves

minaminao

permission denied 3

Misc

Medium

115 solves

baumroll1234

Vending Machine

Misc

Easy🌱

177 solves

hiikunz

reused n

Crypto

Medium

116 solves

rsk0315

Bounds Checking

Pwn

Hard

87 solves

serioton

Mirage

Rev

Easy🌱

124 solves

minaminao

hidden service

Misc

Medium

102 solves

tchen

Super Short Python Golf

Misc

Medium

117 solves

minaminao

Equation Cipher

Crypto

Medium

101 solves

tan90909090

curl as a service

Web

Misc

Medium

113 solves

k0080

Please Link This

Pwn

Hard

77 solves

tan90909090

curl as a service 2

Web

Misc

Hard

89 solves

shiragi

Flag for Switch

Web

Easy🌱

153 solves

pppp4649

Small d

Crypto

Medium

102 solves

tchen

Kakuzuke

Web

Medium

106 solves

kakur41

Python:Impossible

Misc

Medium

105 solves

nozokare

Time Travelers' OTP

Web

Medium

81 solves

minaminao

Even Worse RSA

Crypto

Hard

56 solves

k0080

Conquer Ultimate Device Abyss

Rev

Hard

52 solves

minaminao

Catrunner

Misc

Easy🌱

73 solves

baumroll1234

Planned topicRSA

Crypto

Medium

tchen

Planned topicCSP

Web

Medium

Coming soon

pppp4649

Planned topicRSA

Crypto

Medium

rsk0315

Planned topicXSS

Web

Hard

ptr-yudai

Planned topicStack

Pwn

Hard

Want a harder challenge?

Go to B-SIDE

Writeups

Daily AlpacaHackに挑戦するつくよみちゃん 05/24 rev/Conquer Ultimate Device Abyss/k0080

tsukuyomi-chan

Conquer Ultimate Device Abyss

17 hours ago

Writeup for Conquer Ultimate Device Abyss

tadanobutubutu

Conquer Ultimate Device Abyss

18 hours ago

Writeup for Conquer Ultimate Device Abyss

goroshirow

Conquer Ultimate Device Abyss

19 hours ago

Writeup for Conquer Ultimate Device Abyss

nozokare

Conquer Ultimate Device Abyss

19 hours ago

Writeup for curl as a service 2

nozokare

curl as a service 2

19 hours ago

Writeup for Even Worse RSA

nozokare

Even Worse RSA

19 hours ago

Writeup for Even Worse RSA

tadanobutubutu

Even Worse RSA

2026/05/23 20:59

Daily AlpacaHackに挑戦するつくよみちゃん 05/23 crypto/Even Worser RSA/minaminao

tsukuyomi-chan

Even Worse RSA

2026/05/23 18:10

Writeup for Even Worse RSA

baumroll1234

Even Worse RSA

2026/05/23 16:45

Writeup for Even Worse RSA

goroshirow

Even Worse RSA

2026/05/23 16:39

Rows:

Time Travelers' OTP

Topic: One-Time PasswordReleased: May 22, 2026

81 solves

Web

Medium

nozokare

USER	SOLVED AT
n0v4	5 hours ago
bassamassiri	11 hours ago
zyagaimo-jp	21 hours ago
ly4	2026/05/23 14:13
tat	2026/05/23 11:10
now4est	2026/05/23 10:51
hiroyuki	2026/05/23 09:57
despair09	2026/05/23 06:42
kumabear	2026/05/23 05:25
ctf-udon	2026/05/23 03:35
tsukuyomi-chan	2026/05/22 19:40
tenagazaru	2026/05/22 14:53
cfba82eb	2026/05/22 14:52
4141414141	2026/05/22 14:33
tyage	2026/05/22 14:22
labpump	2026/05/22 14:00
trimscash	2026/05/22 13:31
kowerkoint	2026/05/22 13:13
yasoikawa2	2026/05/22 12:51
blackade	2026/05/22 12:28
baumroll1234	2026/05/22 12:22
ss8888888	2026/05/22 12:14
koufu193	2026/05/22 12:14
reid	2026/05/22 12:06
roaris	2026/05/22 11:57