Into the symmetry

See  also Part I and Part II  of this series
This is going to be a short blog post about the (in)famous Micali-Schnorr  Random Number Generator (MS-DRBG). See Part I and Part II  of this series  for more information about this topic.


WHO: NIST published the specification for Micali-Schnorr  Random Number Generator (MS-DRBG) in NIST Special Publication 800-90 ISO 18031.  Along with the explanation of the core algorithm the documents contains the specification's moduli with the claim to be of the form  n = pq with p = 2p1 + 1, q = 2q1 + 1, where p1 and q1 are (lg(n)/2 – 1)-bit primes.
N.B. a prime of the form p = 2p1 + 1 where p1 is also a prime goes under the name of Safe Prime and they are often used in cryptography for both RSA and DH.
WHAT: Now we can look at the NIST Special Publication 800-90 ISO 18031's moduli and simply believe that those modulis are of the claimed form but maybe is not a great idea (see the WHY section). Going to N(SA)IST and just asking for the factori…

People that knows me well are well aware that prime numbers have been my obsession since my childhood andtheyare source of continue interest for me. Actually thanks to cryptography they are a relevant part of my everyday life. One of the most important problem in cryptography since the discovery of RSA is factoring. The factoring problem consists of finding the prime numbers p and q given a large number , N = p x q.
Unless you are still convinced that factoring is an easy peasy problem, you should know that, while probably not NP-complete, factoring is indeed reaaally hard.
The faster known method for factoring is currently NFS (Number Field Sieve) and if you are interested in the topic I suggest you to read  this beautiful article from the great Carl Pomerance titled "A Tale of Two Sieves" . But it is not what I wanted to talk about today, mainly because the complete algorithm and all its shades go well beyond my current knowledge.
Today instead I want to talk you about one…

tl;dr in this blog post I am going to talk about some bug bounty left over with a little rant.

Here you can find bug bounty left over part I and II
Here you can find bug bounty rant part I and II
Introduction In one of my previous post I was saying that: 

"The rule #1 of any bug hunter... is to have a good RSS feed list."
Well well well allow me in this post to state rule #2 (IMHO)

"The rule #2 of any bug hunter is to DO NOT be to fussy with 'food' specifically with left over"

aka even if the most experience bug hunter was there (and it definitely was my case here, given the fact we are talking about no one less than filedescriptor) do not assume that all the vulnerabilities have been found! So if you want some examples here we go.
Part I - GoogleI have the privilege to receive from time to time Google Vulnerability Research Grant. One of the last I received had many target options to choose from, but one in particular caught my attention, namely Google Issue T…