CTF-Crypto
CTF-Crypto copied to clipboard
ValarDragon
RSA tools
Hi,
I was looking at implementing the recovery of private key knowing the n/4 last bits and I saw it was on your TODO list.
Do you have any examples where it has been done by anyone yet ? It looks like there are many articles/surveys about that technique, but no practical implémentation yet... Thanks !
The n/4 last bits attack requires an implementation of bivariate coppersmith. The only bivariate coppersmith implementation I know of is: https://github.com/mimoo/RSA-and-LLL-attacks, so perhaps you can adapt that?
I've also seen CTF teams use the n/4 attack in writeups, just haven't seen an implementation of it.
Ok,thank you for the answer.
I'll dig into the other repository as well. I also found out Sage was using a method called small_roots and it may be related to the coppersmith method.
Small roots is univariate coppersmith, its actually used within the library already!