Crypto: infinite descent

edited April 2018 in Challenges

I've gotten most of the first part (including the private key), but somehow not able to decrypt the message. Using OpenSSL I get a size error "rsa routines:rsa_ossl_private_decrypt:data greater than mod len:../crypto/rsa/rsa_ossl.c:401"

I've tried converting the message to other formats but it seems I'm not on the right path with this, possibly to do with padding used in the OpenSSL implementation. I've given some attempts at doing this in Python without luck either. A nudge on this part would be great.

Comments

  • You don't need openssl for this. Use the fasterprime.py that is given and re-write it to decrypt(), not encrypt().

  • Thanks! That was a quick modification, all the clues for that really were in the code

  • Stuck on 5004911641405... what am i supposed to do with this number please PM !!

  • No need hahaha..i re-looked the zip file saw three file One was not extracted or mistakely delete haha so i it cause lot of commotion!! Now all gud Need help JUST PM me!!

  • If anyone is as inept as me: "Triplet" = Three digits
    gen_and_check only returns up to 0xFF -> that is one character, no matter how big seedval was - so you'll need to break that number up

    Feel free to PM if you need help

    Hack The Box

    GitHub repository with writeups: https://github.com/S7uXN37/HackTheBox

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