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.

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Today's Challenge

Submissions (latest 3)

fulgens

SOLVED!

May 27, 12:17 AM

haihuiliyuyuan

SOLVED!

May 27, 12:16 AM

xnmhuveb

SOLVED!

May 26, 11:58 PM

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🌱

129 solves

serioton

unheard

Misc

Medium

78 solves

minaminao

permission denied

Misc

Hard

82 solves

minaminao

permission denied 2

Misc

Medium

83 solves

admin

Alpaca++

Misc

Welcome🌱

257 solves

tchen

Alpaca Rangers 2

Web

Easy🌱

219 solves

pppp4649

Small N

Crypto

Easy🌱

157 solves

hiikunz

secret-table-2

Web

Medium

146 solves

serioton

do the math

Misc

Medium

115 solves

trimscash

func-array

Pwn

Easy🌱

152 solves

minaminao

permission denied 3

Misc

Medium

116 solves

baumroll1234

Vending Machine

Misc

Easy🌱

178 solves

hiikunz

reused n

Crypto

Medium

117 solves

rsk0315

Bounds Checking

Pwn

Hard

88 solves

serioton

Mirage

Rev

Easy🌱

125 solves

minaminao

hidden service

Misc

Medium

105 solves

tchen

Super Short Python Golf

Misc

Medium

119 solves

minaminao

Equation Cipher

Crypto

Medium

103 solves

tan90909090

curl as a service

Web

Misc

Medium

116 solves

k0080

Please Link This

Pwn

Hard

79 solves

tan90909090

curl as a service 2

Web

Misc

Hard

93 solves

shiragi

Flag for Switch

Web

Easy🌱

164 solves

pppp4649

Small d

Crypto

Medium

106 solves

tchen

Kakuzuke

Web

Medium

112 solves

kakur41

Python:Impossible

Misc

Medium

108 solves

nozokare

Time Travelers' OTP

Web

Medium

88 solves

minaminao

Even Worse RSA

Crypto

Hard

59 solves

k0080

Conquer Ultimate Device Abyss

Rev

Hard

57 solves

minaminao

Catrunner

Misc

Easy🌱

98 solves

baumroll1234

I cannot decrypt RSA

Crypto

Medium

76 solves

tchen

Hello Programmer!

Web

Medium

30 solves

shiragi

Planned topic.NET

Rev

Medium

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

Writeup for Catrunner

nozokare

Catrunner

6 hours ago

Writeup for I cannot decrypt RSA

nozokare

I cannot decrypt RSA

6 hours ago

Writeup for I cannot decrypt RSA

tadanobutubutu

I cannot decrypt RSA

6 hours ago

Daily AlpacaHackに挑戦するつくよみちゃん 05/26/I cannot decrypt RSA/baumroll1234

tsukuyomi-chan

I cannot decrypt RSA

6 hours ago

Writeup for I cannot decrypt RSA

goroshirow

I cannot decrypt RSA

9 hours ago

Writeup for Catrunner

nirvana

Catrunner

15 hours ago

Writeup for Catrunner

tadanobutubutu

Catrunner

2026/05/25 19:33

Daily AlpacaHackに挑戦するつくよみちゃん 05/25/Catrunner/minaminao

tsukuyomi-chan

Catrunner

2026/05/25 16:32

Writeup for Catrunner

baumroll1234

Catrunner

2026/05/25 15:15

Writeup for Catrunner

goroshirow

Catrunner

2026/05/25 15:11

Rows:

Hello Programmer!

Topic: CSPReleased: May 27, 2026

30 solves

Web

Medium

tchen

USER	SOLVED AT
fulgens	16 minutes ago
haihuiliyuyuan	16 minutes ago
xnmhuveb	34 minutes ago
pppp4649	1 hour ago
moz99	1 hour ago
tad	3 hours ago
tadanobutubutu	4 hours ago
nozokare	4 hours ago
logdav	5 hours ago
baumroll1234	5 hours ago
cyanos	6 hours ago
mti	6 hours ago
toomer	7 hours ago
itsuki-t	7 hours ago
roaris	8 hours ago
rsk0315	8 hours ago
kanda-art	8 hours ago
mak0tan	8 hours ago
kurgm	8 hours ago
koufu193	8 hours ago
edwowmath	8 hours ago
goroshirow	8 hours ago
bsvac	8 hours ago
mg7x	8 hours ago
nanashiku	8 hours ago

Rows:

description solves