Showing posts with label Cryptography. Show all posts
Showing posts with label Cryptography. Show all posts

Sunday, 12 July 2015

Padding Oracle Attacks : The other padding that killed your secret key


The Oracle of Delphi
Hi folks! In this post I'd like to talk about something that's pretty old but still crops up every now and then (example). I know for most folks this is nothing new but I'd still like to have a post about this attack in my archive and also deliver a good explanation of the attack in a way that makes it easier for more people to understand (I know for new comers this attack can be a bit of a mind bending exercise :P). Also if you want to be a total infosec / crypto hipster you can refuse to call it padding oracle attacks and call it by its eponym "the Vaudenay attack" and pay homage to the inventor Serge Vaudenay :)

Update: The next post is a more practical explanation of this attack :)







Saturday, 17 August 2013

Homomorphic Encryption : What it is and what it means for the future of security


There's a new idea brewing in the cryptographers' circles called Homomorphic encryption, and it will soon change the way we do everything from querying databases remotely to adding numbers. In this post I briefly explain what homomorphic encryption is and then list a few ideas others have had on how to use it in cool ways and one or two ideas I've had.

Given that this is a relatively new idea, many of you may be hearing about it for the first time; I'm going to spend a few paragraphs explaining what it is and at the end of this post I'll share a couple of papers and blog posts by awesome people on the subject and its applications.

Tuesday, 19 March 2013

Hash Length Extension: The padding that killed your secret key

Its been a while folks! but I'm back with another really interesting post, this time about how to abuse hashing algorithms or rather a certain style of hashing algorithms.

I'm going to try to teach you the analysis that gave birth to this very clever attack and to do that I need to talk a little about hashing algorithms and how they are constructed, I mean its not just coincidence that collisions in hashing functions are extremely rare.