I need some help in the "Classic yet complicated" challenge. Please guide me.

I cant figure out what to do as I am a beginner and trying to learn.

i stuck in this too.

I’d give it a go with an old cipher…There was this French dude called Blaise though :wink:

@n3m0 said:
I’d give it a go with an old cipher…There was this French dude called Blaise though :wink:

Perfect Hint :wink:

@n3m0 said:
I’d give it a go with an old cipher…There was this French dude called Blaise though :wink:

yes but i dont get it the key is the flag so in the cipher the key should be HTB???

I found this tool really helpful!! JcrypTool. Just download it and play around with it!! It’ll get you 90% there and then just take a little 10% leap at the end for the solution!!

@GRIMREAPER said:
yes but i dont get it the key is the flag so in the cipher the key should be HTB???

Perhaps changing the keysize would help?
Remeber to look at repeated patters :slight_smile:

HINT: Its all about the frequency
Also, remember:
“Flag format : HTB{key in lowercase}”

@n3m0 said:

@GRIMREAPER said:
yes but i dont get it the key is the flag so in the cipher the key should be HTB???

Perhaps changing the keysize would help?
Remeber to look at repeated patters :slight_smile:

HINT: Its all about the frequency
Also, remember:
“Flag format : HTB{key in lowercase}”

I am a rookie and I do not know anything about all this . I am doing this for the first time. COuld you please be clear so that i learn it for the first time atleast.

@n3m0 said:
I’d give it a go with an old cipher…There was this French dude called Blaise though :wink:

This is a perfect hint. Research who this guy was. Then, you can use a tool like JCrypt or a site like this one: https://www.dcode.fr/ to help you decode the text.

On the site, since you don’t know the decryption key, is there an option that might help you just randomly try to guess the right decryption key?

Once you see readable text in English and can read every word, you’ll know you have the right decryption key. Per the challenge hint: " Find the plaintext, the key is your flag! "

Hopefully that’s not too much but enough to help you get started.

@Skunkfoot said:

@n3m0 said:
I’d give it a go with an old cipher…There was this French dude called Blaise though :wink:

This is a perfect hint. Research who this guy was. Then, you can use a tool like JCrypt or a site like this one: https://www.dcode.fr/ to help you decode the text.

On the site, since you don’t know the decryption key, is there an option that might help you just randomly try to guess the right decryption key?

Once you see readable text in English and can read every word, you’ll know you have the right decryption key. Per the challenge hint: " Find the plaintext, the key is your flag! "

Hopefully that’s not too much but enough to help you get started.

This is more than enough info to solve this challenge, and probably 80% of the rest of the crypto challenges. The only one’s I’ve seen that can’t be solved with JCrypTool alone are the two high-point ones, Ebola and … Infinite Descent. As far as I remember.

pls hint … i did not find key…where should i look?

pm

The tool I used was CryptoCrack:

@andrewh said:
I found this tool really helpful!! JcrypTool. Just download it and play around with it!! It’ll get you 90% there and then just take a little 10% leap at the end for the solution!!

Yes I was trying a lot of different things and JCrypTool made it really easy

So I was able to decipher the text with jcrypt after messing around with it for a while. I still can’t get the flag though, I’m not sure as to what to do next.

@witchkingsteve said:
So I was able to decipher the text with jcrypt after messing around with it for a while. I still can’t get the flag though, I’m not sure as to what to do next.

HAHAHA I was staring the flag the entire time

I truly hate guessing games. First you guess the algorithm, then the key. What’s the point?

Found it by accident. Well, there are two attacks for this cipher and I tried the first examination, which should work.

dcode.fr is very good too.