685 reputation
219
bio website en.wikipedia.org/wiki/…
location United Kingdom
age 26
visits member for 2 years, 4 months
seen Mar 27 at 12:08

Pentester, ex-developer, security researcher, reverse engineer, electronics tinkerer, internet activist, zombie eradicator, promulgator of useless facts, shrubbery inspector, bacon aficionado.

Strengths: Security, Crypto, Win32 API, C#, .NET, PHP, x86 assembly

All answers and comments are encrypted with ROT256-ECB.

Opinions are my own. Advice provided with no warranty.


Oct
10
comment How is it possible to parallelize a hashing function to crack an iteratively hashed password?
An important point to make is that a GPU is essentially a large parallel arithmetic unit. Think of it as a 256-core (or more) CPU with little/no ability to do branching (if/then/else), but a particularly strong ability to perform scalar calculations. Most hash functions can be expressed almost entirely as a series of scalar calculations, which means that it's possible to use a GPU to perform lots of them at once.
Oct
10
comment Avalanche noise RNG for one-time pad use
Avalanche noise isn't particularly invulnerable to external EM, either. With a decent antenna and some maths you can skew the generator, or at least disrupt the quality of the random source. If you're looking at NESSIE spec security or similar, an attacker with physical proximity to the device should most definitely be considered a potential threat.
Oct
10
comment In layman's terms, how does Shor's algorithm work?
That's actually a really great way of explaining it.
Oct
6
comment In layman's terms, how does Shor's algorithm work?
@RickyDemer Maybe, but isn't the whole scary part that it can factor semiprimes in polynomial time, thus rendering a good portion of our current asymmetric ciphers broken?
Oct
3
comment Is 512-bit RSA still safe for signature generation?
@ThomasPornin Good point. I'll switch to 1024 for now, and I'll find a WinXP box to test 2048-bit on.
Oct
3
comment Is 512-bit RSA still safe for signature generation?
@ThomasPornin Interesting. I read on MSDN that the base CSP was 512-bits and shipped with the OS, and it implied (or, rather, I inferred) that you have to manually download the expanded CSP. Am I wrong in this assumption?
Oct
2
accepted Is 512-bit RSA still safe for signature generation?
Oct
2
comment Is 512-bit RSA still safe for signature generation?
@Thomas Yikes. I'll see if I can find a pure-managed implementation of RSA then, so I can use 2048-bit keys.
Oct
2
comment Is 512-bit RSA still safe for signature generation?
Is there a decent projection of the time it'd take to break a 512-bit key today?
Oct
2
asked In layman's terms, how does Shor's algorithm work?
Oct
2
asked Is 512-bit RSA still safe for signature generation?
Sep
14
comment Why RSA can't handle numbers above 76?
Interesting question. I'm guessing the answer is something to do with the number of bits you can encrypt with such low p and q (or e and d in your case) values, but I'm unsure as to how the modulus affects this. This question would be better on Crypto SE though, so I've flagged for a moderator to move it.
Aug
22
comment Security considerations for partially shared password databases
LastPass is the only solution I'm aware of. It's web-based. However, it's a "freemium" service, so you do have to pay for certain features. I'm actually working on exactly the same sort of idea, except as a client/server app for commercial environments that require shared passwords. Obviously, it could be used at home, too. I aim to make it open source.
Aug
20
accepted Entropy of system data - use all and hash, or trim least significant bits?
Aug
4
comment Blum Blum Shub vs. AES-CTR or other CSPRNGs
Absolutely wonderful answer. I had no idea about the caveats in its security proof - I'm now rather surprised that BBS gets mentioned as a functional CPSRNG at all!
Aug
3
asked Blum Blum Shub vs. AES-CTR or other CSPRNGs
Jul
23
comment How much would it cost in U.S. dollars to brute force a 256 bit key in a year?
This is post number 1337 :)
Jul
23
comment Memory-hard operations in work-factor hash functions
So state = sha512(state) + state would work?
Jul
23
revised Memory-hard operations in work-factor hash functions
Much shorter code.
Jul
22
comment Is this a secure implementation of password reset email?
That's true -- a simple hash should (probably) do the trick. However, I'd still prefer something like bcrypt, since it protects you from most weaknesses you might discover in the PRNG used to generate the tokens.