Medium Live

RSA Noob

60 points

1755 Solves

Cryptography

Medium

intelagent moderator badge ctflearn++ badge

Community Rating: 4.43 / 5

These numbers were scratched out on a prison wall. Can you help me decode them? https://mega.nz/#!al8iDSYB!s5olEDK5zZmYdx1LZU8s4CmYqnynvU_aOUvdQojJPJQ

First 10 Solvers

Rank Username
1 voidmercy
2 limyunkai19
3 nandayo
4 emperorlepone
5 ross3102
Rank Username
6 greglatronica
7 krispursiainen
8 aglickman
9 niclev20
10 daniellacalle

  • Peder ctflearn++ badge

    Protected

    [REDACTED] This comment is only shown to users who have solved this challenge.

  • FelixGB

    I'm totally new to RSA algorithm. I read the RSA Wiki and saw the equations ... not sure if we are suppose to simply try to figure out P / q or if we really need them or suppose to try to decode the equations? So far ... I've spent hours and still on square 1 >.<

    • intelagent moderator badge ctflearn++ badge

      Check out the Wikipedia article for rsa cryptosystem!

    • pjrox

      Note that Crypto.Util Library is a must to solve RSA... I too found it out today

  • korsasupreme

    Solved this call on Go, on python it would be much easier.

  • 95ych

    lol , rip RSA sense for that value of e

  • wojtek9022

    After 2 hours of searching i was frustrated, but after all I pretty happy that i didn't give up and i learned something new

  • sharkmagic07

    Protected

    [REDACTED] This comment is only shown to users who have solved this challenge.

  • Ebhodini

    How to calculate phi(n) when n is so enormous?

    • Crucizer

      I don't think that the value of phi(n) depends on n. You can use the formula (p-1)(q-1) to calculate phi(n).

      • Crucizer

        Okay, I just realised p,q weren't given so, can you tell me how to calculate n?

        • CVCodes

          It seems the question has n as being phi(n) already as it seemed to work still with just using the n value given in the question to get the flag

  • Jeltzin

    Protected

    [REDACTED] This comment is only shown to users who have solved this challenge.

  • Crucizer

    Can anybody tell me what does the 'c' no, stands in the text? I can understand the 'd' and 'e' numbers, but not the 'c' one.

  • Theriphunters

    Protected

    [REDACTED] This comment is only shown to users who have solved this challenge.

  • warmachine86

    Protected

    [REDACTED] This comment is only shown to users who have solved this challenge.

  • technophobian

    Protected

    [REDACTED] This comment is only shown to users who have solved this challenge.

  • arklegru

    It turns out, if you take a shortcut you don't need to calculate phi, p, or q.

  • Salkos

    Protected

    [REDACTED] This comment is only shown to users who have solved this challenge.

  • ryankag

    Protected

    [REDACTED] This comment is only shown to users who have solved this challenge.

  • bh11235

    Too much time spent staring at the line "e=1"

  • SHaNTuDe

    Protected

    [REDACTED] This comment is only shown to users who have solved this challenge.