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2022 justCTF writeup

2022 justCTF writeup


Frosty

Name Category Points Solves
Frosty CRYPTO 228 / 500 39

Description

I just found this great new multisignature scheme, we can collaborate to sign messages together!

nc frosty.nc.jctf.pro 4444

PS: The connections are dropped automatically after 4 minutes.

Attachments

See attachments.

Solutions

See solutions.


fROSty’s Second Signature Scheme

Name Category Points Solves
fROSty’s Second Signature Scheme CRYPTO 275 / 500 25

Description

Distributed key generation is hard, so just use the keys below. No more funny stuff, OK?

Your private key share: 0xee669fa9dc3e12154d13ac6bc17d6c3b2291832dadd76746
My public key share: (0x9532cae35947c6211c2f808145aa193f9773e591b03f3e1b, 0x3df6739646175efd21fe509d8b1f436fa4f6663b4eec9641)

Use one of the servers below (ams=Amsterdam, nyc=New York, sgp=Singapore):
nc very-frosty-ams3.nc.jctf.pro 4445
nc very-frosty-nyc3.nc.jctf.pro 4445
nc very-frosty-sgp1.nc.jctf.pro 4445

PS1: Solve the task locally first.
PS2: The connections are dropped automatically after ~10 minutes.

Attachments

See attachments.

Solutions

See solutions.


Simply Powered

Name Category Points Solves
Simply Powered CRYPTO 260 / 500 29

Description

Just calculate root. :)

# Use only one server:
nc simply-powered-ams3.nc.jctf.pro 4444 # 142.93.236.95
nc simply-powered-nyc3.nc.jctf.pro 4444 # 159.203.115.238
nc simply-powered-sgp1.nc.jctf.pro 4444 # 167.172.66.141

Attachments

See attachments.

Solutions

See solutions.


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