808 reputation
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bio website en.wikipedia.org/wiki/…
location United Kingdom
age 26
visits member for 2 years, 11 months
seen Oct 20 at 16:03

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.


May
27
comment Galois fields in cryptography
This is an amazing answer. I get it now! :)
May
26
comment Is it secure to use the hash of key as the IV in AES encryption?
@CodeInChaos Paranoia! :)
May
25
comment Galois fields in cryptography
I'm still lost. I understand vectors as a small set of numbers. So, a vector has a size and a set of values - essentially an array. A vector $[a,b,c,d]$ has a length of 4 and four values - $a$, $b$, $c$, and $d$. If a field is a set of vectors, I envision it as: field = array(array(a1,b1,c1,d1),array(a2,b2,c2,d2),...). Is this correct? If so, how are a1, b1, etc. computed initially, ignoring operators? Or do we just populate them with something (e.g. a key) and then do operations on them?
May
25
accepted Standard symbol / notation for “x knows y”, or the inverse
May
25
comment Standard symbol / notation for “x knows y”, or the inverse
@CodeInChaos I was just using it as an example. If I were really writing that in a document, I'd put something like "where $f(x)$ runs in polynomial time or better".
May
25
comment Standard symbol / notation for “x knows y”, or the inverse
So you're saying there's no such notation?
May
25
asked Standard symbol / notation for “x knows y”, or the inverse
May
25
accepted Is every output of a hash function possible?
May
25
revised Galois fields in cryptography
example
May
25
revised Galois fields in cryptography
update
May
25
comment Galois fields in cryptography
<<*snip*>> - I've put this comment as an update to the question.
May
24
asked Galois fields in cryptography
May
24
comment Memory-hard operations in work-factor hash functions
@CodeInChaos I am using scrypt, in my production code. This is just something I'm playing with out of interest, to see how I might go about creating a memory-hard hash function.
May
24
comment After implementing a novel encryption algorithm, how would one go about analyzing its security or get help from others in doing so?
Can't +1 poncho's comment enough. Learn to break ciphers! I aso recomment Stanford's free crypto course.
May
24
comment After implementing a novel encryption algorithm, how would one go about analyzing its security or get help from others in doing so?
I think you misunderstood. I'm saying that you shouldn't use your own schemes in practice, for any form of security mechanism in a production environment. You can devise your own schemes and get critique to learn about crypto, but please don't ever use your own cipher to secure sensitive information. Real ciphers have been developed by serious crypto gurus and vetted by hundreds of other serious crypto gurus, over a period of many years. Not a single one of them would use their own cipher without years of peer review and revision.
May
24
asked Memory-hard operations in work-factor hash functions
May
24
comment After implementing a novel encryption algorithm, how would one go about analyzing its security or get help from others in doing so?
If you're considering them as an actual security measure, forget it. Crypto is a field where "rolling your own" is a very bad idea.
May
23
asked Is every output of a hash function possible?
May
23
comment Is it secure to use the hash of key as the IV in AES encryption?
@CodeInChaos It's not intended to be some hair-brained "increase the entropies!" scheme, if that's what you're concerned about. The idea is to xor the IV with the hash when storing it in the file, so it can't be known by an attacker without knowing the password.
May
23
comment Is it secure to use the hash of key as the IV in AES encryption?
A solution to this is to store a random IV in the file header, xor'ed with the hash of the password. When you decrypt, compute the password hash and xor against the stored value, then use the result as the IV. This gives you a safe way to store the IV, and a unique IV per file.