[crypto] Flippin_Bank

let’s go

Very nice challenge I like this type of crypto, I’ve done little bruteforce in the end because something appeared 16 bytes far away of my calculation but in the end it’s not so difficult just look at the encryption mode of operation

Thanks for the challenge P3t4. Was fun.

Nice challenge but a little bit overpriced, 10 points is more than enough

Very nice and educational challenge

Cool challenge. Finally some modern crypto here. No brute force required - just understand the attack and flip away.

got it, cool challenge, feel free to PM me

The unintended solution has been patched. I am very sorry about that.
Thank you guys for your feedback!

Is it normal that the server does not respond? Nvm I looked for a web interface and didn’t read the instructions… :-1:

I just can’t recreate what hex() does and how to do the decryption

Do we have to bruteforce this? Can anyone give me a nudge please?

dm me

I’ve never done this before so I had to do some research, and then analyze what the app is doing. This was an excellent learning exercise about this kind of crypto. I feel like I just did a homework assignment out of a cryptanalysis textbook.

No brute force required but it will require a bit of reading the code and analyzing aspects of the cipher algorithm to know what to manipulate without messing everything else up. You won’t need to get into intricate algorithmic details, just basic structure. It’s all right there though.

Kind of stuck. My cryptoanalysis only went as far as noticing common patterns with different username/password combinations…nudges would be greatly appreciated!

Would appreciate a little bit of help to this one as it is the first time I’m dealing with crypto and I would like to learn something new. Thanks

Thanks a lot to @alienum , I finally got it in the end, Nice challenge.

Great @P3t4 !! Very nice and educational challenge. However, i have some doubt. Someone to discuss about it?

If you have questions, feel free to PM me.

the name of the challenge is a big hint everyone :slight_smile: i suffered a couple of hours reading up on crypto until i stumbled on the attack that has to be done here

@federella and @Szkiel you can pm me if need it

Amazing challenge, definitely glad to have done this, thank you!!