Cyber Apocalypse CTF 2021 #Crypto #phase stream 1

According to detail given:

Encrypted data : 2e313f2702184c5a0b1e321205550e03261b094d5c171f56011904

Known text : CHTB{ [as all flag start with this]

Encyption Type:XOR

Key length : 5 bytes

Key : ?

Data:?

First Encrypted Data xor Known text (for that i use cyber chef)

now we have found KEY = mykey

Now we can use this key to decrypt the msg but first we have to convert Encrypted data which is is in hex form to non hex form (again cyber chef but due to browser encoding we have to convert it into base 64 and then decode on local machine to get actual data)

after decoding it from base 64 on local machine

now this python script to get flag

where cipher.txt over data which we decode from base64 (from hex)