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)

ost

SOLVED!

Mar 16, 3:23 PM

toomer

SOLVED!

Mar 16, 3:19 PM

mak0tan

SOLVED!

Mar 16, 3:14 PM

Leaderboard

Period

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.

Mar 2026

Solved

Unsolved

Upcoming

Mon

Tue

Wed

Thu

Fri

Sat

Sun

kakur41

Alpaca Quest

Rev

Medium

106 solves

minaminao

hit-and-hit

Misc

Medium

81 solves

tchen

Alpaca Rangers

Web

Medium

132 solves

kurenaif

One Byte Padding Oracle Attack

Crypto

Hard

69 solves

tchen

Rock Paper Scissors Lizard Spock

Web

Hard

88 solves

minaminao

pyjs

Misc

Hard

77 solves

admin

Alpaca meets QR

Misc

Welcome

206 solves

kakur41

Bars

Web

Easy

207 solves

tan90909090

glibc's secret function

Rev

Easy

152 solves

minaminao

Flag Printer 2026

Misc

Easy

155 solves

tchen

Alert my Flag

Web

Medium

130 solves

mora

magic number

Misc

Medium

105 solves

theoremoon

high and low

Crypto

Hard

78 solves

ark

guess.js

Misc

Hard

89 solves

minaminao

FLAG OVER

Misc

Medium

102 solves

ark

💯

Misc

Medium

100 solves

pppp4649

Find XOR key

Crypto

Easy

104 solves

colza

kappa overflow

Pwn

Medium

103 solves

tchen

Another Login Challenge

Web

Medium

93 solves

asusn

Heuristic IPPON

Misc

Easy

132 solves

minaminao

flag.txt

Misc

Hard

90 solves

pppp4649

The future path

Crypto

Medium

76 solves

tchen

Free Coupon

Web

Medium

16 solves

Coming soon

chocorusk

Planned topicObfuscation

Rev

Hard

k0080

Planned topicBOF

Pwn

Hard

Coming soon

Want a harder challenge?

Go to B-SIDE

Writeups

Writeup for flag.txt baumroll1234 ja flag.txt 23 hours ago
Writeup for Alert my Flag yeon-seok ko Alert my Flag yesterday
Writeup for Daily AlpacaHack 3/8-3/14 kakur41 ja guess.js +6 yesterday
Writeup for Heuristic IPPON baumroll1234 ja Heuristic IPPON yesterday
Writeup for kappa overflow colza author ja kappa overflow 3 days ago
Writeup for Find XOR key ken1220 ja Find XOR key 4 days ago
Writeup for Find XOR key pppp4649 author ja Find XOR key 4 days ago
Writeup for 💯 baumroll1234 ja 💯 5 days ago
Writeup for 💯 goroshirow ja 💯 6 days ago
Writeup for guess.js goroshirow ja guess.js last week

Rows:

RRe_Time_Limiter

Topic: Number TheoryReleased: Feb 5, 2026

167 solves

Crypto

Medium

Author:

kanon

Waiting for "love" amid these monotonous days, only to end up declaring, "Life's boring after all!" by ...

rre-time-limiter.tar.gz

description solves writeups