395 reputation
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location Wellington, New Zealand
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visits member for 2 years, 4 months
seen 9 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.


Dec
19
comment Gold Standard for password hashing
I should mention it here again, the 2^61 collision attack on SHA-1 (and even the 2^80 birthday attack) is irrelevant to password hashing..
Dec
18
comment Is my developer's home-brew password security right or wrong, and why?
@jmoreno In general, security by obscurity is perceived as a crutch for poor cryptography practices, and it often is. That doesn't mean it doesn't have value - it does have its uses, but in this situation it is not warranted.
Dec
18
comment Is my developer's home-brew password security right or wrong, and why?
@jmoreno Still doesn't justify his useless scheme.
Dec
16
comment How to authenticate a salted password?
Just thought I should mention the obvious, in case somebody gets the wrong idea: a 32-bit hash is not secure.
Dec
14
comment Is there value in storing passwords in their own table with encrypted or hashed keys?
And where do you propose the secret key be stored? If it's on the server, why should the hypothetical "hacker" not be able to get a hold of it if it can access the password and user tables?
Dec
14
comment Is it possible to decrypt symmetric key encryption without the key?
@NAlex No, I'm saying modern cryptography assumes plaintext is known and algorithms must ensure the key remains secret even under those circumstances. It would be a mistake to assume the attacker doesn't know the plaintext, because more often than not, he does.
Dec
13
comment Why don't people hash and salt usernames before storing them
Welcome, 21840c1a3e3db69e01445c8782a99f9b.
Dec
13
comment Is it possible to decrypt symmetric key encryption without the key?
The plaintext must not be assumed to be secret - at least parts of it are probably known to the attacker (common headers, etc...). There are also real life protocols which allow an attacker to obtain unlimited amounts of plaintext/ciphertext pairs, if your encryption scheme yields the key under those circumstances it has failed.
Dec
9
comment How difficult to crack keepass master password?
Moore's Law is starting to fail already - thermal limits have been reached for semiconductor transistors and the future is all about parallelization, which scales linearly, not exponentially.
Dec
1
comment How effectively can ISPs detect illegal file sharing?
@Rob Ignorance, mostly. Most people don't know about encryption, or think it doesn't help them, or mistakenly believe it slows down their downloads (it doesn't). There's been some progress in educating users but it hasn't reached out much so far, so I really do not believe most torrent clients are set to use encryption. I could, of course, be wrong.
Nov
19
comment How is the available entropy in /dev/random calculated (or estimated)?
@everyone remember this was an answer posted from crypto.SE with a different perspective on the problem. Though I have to agree it doesn't really address the question which is really about how the kernel comes up with this entropy estimate.
Nov
6
comment Can I encrypt a file incrementally?
@D.W. There are also hash tree approaches to allow MAC verification of individual packets to arbitrary granularity, but I'm not sure how practical they actually are, you still to receive most of the tree before you can begin checking and the overhead can be considerable.
Oct
31
comment How can I encrypt a file with .NET and have the same file size of the original file?
Yes, with the edit it's now clearer.
Oct
31
comment How can I encrypt a file with .NET and have the same file size of the original file?
Keep in mind the IV must sometimes be unpredictable in addition to being unique.
Oct
23
comment Why do we lock our computers?
@TC1 or a post-it next to the keyboard..
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)