395 reputation
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location Wellington, New Zealand
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visits member for 2 years, 1 month
seen 3 hours ago

I am an undergraduate computer science and mathematics student in New Zealand. My fields of interest are computer graphics, in particular the physics of light transport, and to some extent cryptography, as well as programming and software development in general.


Oct
10
comment Will this work? Revealing identity (facebook) of person who clicks specially crafted link
The reason this link works is because you have cookies on your computer telling Facebook which account you want. The proxy website will not have these cookies and Facebook will not know what to give it, thereby returning a login page.
Oct
8
comment How to protect encryption key while application is using it
You can always delete the keyfile once your application has read the key in, and rewrite it before your application closes, if that's possible. It'll still be somewhere on the flash drive but much harder to find. But in general, if the user can read the system's RAM, all hope is lost. This belongs on IT Security, btw.
Oct
7
comment Why do most hashing functions produce hashes that have characters a-f 0-9?
Hash functions output a string of bits. The way you display them textually doesn't change their nature, only their encoding.
Oct
3
comment Why would a virus writer bother to check to see if a machine is infected before infecting it?
The user might also get a physical notice from his ISP about unreasonable email activity, which would be a suicide move for the virus.
Sep
24
comment Computational Feasibility of finding 'Good Links' of the following format
@Polynomial The server could also still accept your requests, but automatically return "no image" regardless of what you passed it, making your probability of success effectively zero, with no way for you of knowing (not very useful in this situation but can be a very powerful deterrent in some situations, in particular people trying to guess passwords)
Sep
11
comment How to check if someone is in my computer
Real hackers don't use the network to remote-control your computer, they use a butterfly with very accurately timed wing flaps, creating small changes in atmospheric pressure, which in turn causes electromagnetic radiation to hit your computer, flipping specific bits in memory thereby allowing them to alter your system's state to their advantage.
Sep
10
comment Encryption and compression of Data
@lynks It is not, however, a definitive test of randomness. If the encrypted file does not compress, your cipher isn't a complete joke, but may still very well be insecure in the extreme. If the encrypted file does compress, all hope is lost and you may as well hand over the plaintext to the bad guys.
Sep
2
comment Have anyone tried to extract the encryption key from a SSD?
There now exist specialized modes of operation for wide block encryption specifically tuned for disk encryption - see CMC, EME. Of course, actually using them is a whole different matter.
Aug
29
comment Safely disable firewire/thunderbolt, patching up DMA exposure
There's something called a jumper that'd like to say hi to your BIOS/EFI password :p
Aug
29
comment Can you encrypt a password using that password itself?
How would you recover MySecretKey once you've encrypted it with itself as the key? :)
Aug
21
awarded  Caucus
Aug
21
awarded  Constituent
Aug
12
comment What are the security measures taken on GPS transmissions?
"Dude, I'm gonna poison this guy's GPS reception so he gets lost in the woods!"
Aug
8
comment Sensitive information I don't want my work to backup
Print an encrypted version, then decode it at home. Oh, wait...
Aug
4
comment How does disk encryption mounting work with large disk and low RAM?
@ewanm89 yeah well at this point it becomes more of a terminology issue, in a sense it does become the new block size (but I see your point). :)
Aug
4
comment How does disk encryption mounting work with large disk and low RAM?
@ewanm89 Threefish has a 256-bit block size variant along with 512-bit and 1024-bit ones (it is a wide block cipher since it was designed for hashing in mind, see Skein). But anyway full-disk encryption uses modes of operation which expand the cipher's block size to the size of a disk sector, so it's not really relevant.
Aug
4
comment Is there an index of all md5 collisions?
@Polynomial I meant SHA256 if the application is security-sensitive, the "otherwise" was a bit ambiguous, sorry. If speed was a real concern I would go for something like Skein though, but I agree that SHA-1 would be somewhat faster than SHA256 (but then I'm pretty sure a caching system would be dominated by disk latency/throughput, making speed irrelevant overall, but this is speculation).
Aug
4
awarded  Commentator
Aug
4
comment Is there an index of all md5 collisions?
Also, the concept of checking against a "collision blacklist" is so anti-KISS that my eyes are bleeding. If an attacker can create one collision, he can most certainly create another, making your blacklist useless.
Aug
4
comment Is there an index of all md5 collisions?
If your caching system doesn't need to worry against a malicious entity trying to create collisions, then you can safely use MD5 - if it's just your program against lady luck, the probability of stumbling upon a collision is basically zero. Otherwise, I recommend SHA256.