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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
21
comment Why is asymmetric cryptography bad for huge data?
No, the ratio is fine, but I was just noting that the speeds you quoted are generally only obtained when you hardcode everything in a very tight loop, with zero function calls or parameters, in assembly. In any realistic application this is simply not logistically viable - you need the code to be modular and flexible so that it can be reused easily. OpenSSL uses a decently optimized AES-NI implementation and AES-128-CBC runs at 720MB/s per core on my overclocked i5 (openssl speed -evp aes-128-cbc).
Dec
21
comment Why is it important that phi(n) is kept a secret, in RSA?
@PaŭloEbermann That is true, and the reason this answer is meant to be complimentary to CodesInChaos's one (expanding on his second point). That said, $n$ might be used in multiple cryptographic primitives (not just RSA) in any given protocol, so assuming you know $\varphi{(n)}$ (which in itself is rather contrived) you will want to get $p$ and $q$ to help attack those parts of the protocol as well, depending on what your goals as an attacker are.
Dec
20
comment Is there a field guide to ECC for the IT Security layman?
Perhaps more importantly, it also helps you identify and steer clear of snake oil..
Dec
20
comment Is there a field guide to ECC for the IT Security layman?
This applies to high-level protocols, of course - implementing your own cipher is almost always a terrible idea because that actually requires years of training and analysis, whereas by just putting together cryptographic constructions you are using existing primitives which are assumed to have specific properties, which you can use to prove your construction is secure assuming the underlying primitives are (which is more reasonable).
Dec
20
comment Is there a field guide to ECC for the IT Security layman?
I disagree about your comment - while a certain amount of standard, general-purpose schemes already exist for most situations, it is sometimes necessary to roll your own cryptographic protocol for your particular use-case. Knowing the difference between a HMAC and a KDF, what IND-CCA means and what a birthday attack is, is crucial to get it right, or at least not fail as much. Seriously, someone has to implement all of this at the end of the day, and if you have the skills, why the hell wouldn't you apply them? Security professionals are not superior beings, they are humans like you and I.
Dec
20
answered Why is it important that phi(n) is kept a secret, in RSA?
Dec
20
reviewed Edit suggested edit on Why is it important that phi(n) is kept a secret, in RSA?
Dec
20
revised Why is it important that phi(n) is kept a secret, in RSA?
added site tags
Dec
20
comment Why is asymmetric cryptography bad for huge data?
Sorry but those AES-NI numbers are ludicrous and are heavily artificial. The latest processors can get a per-core throughput of 800-900MB/s at best in a real implementation with a proper mode of operation. Your point still stands but remember marketing benchmarks are not representative of real life performance.
Dec
19
revised AES vs Blowfish taking key-length into account
added 168 characters in body
Dec
19
comment AES vs Blowfish taking key-length into account
@AlexandreYamajako That is quite true and a fair point that I hesitated to put in my answer, Blowfish has not received nearly the same amount of cryptanalytic attention as AES. I will add it now.
Dec
19
answered AES vs Blowfish taking key-length into account
Dec
18
comment Attacks on the RSA Cryptosystem
en.wikipedia.org/wiki/Coppersmith's_Attack
Dec
18
comment Attacks on the RSA Cryptosystem
This doesn't answer the question. There is, in fact, a specialized attack which allows one to factor N faster than testing all the missing bits when you have enough bits of $p$.
Dec
17
revised Can the encryption exponent e be greater than ϕ(N)?
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Dec
17
revised Can the encryption exponent e be greater than ϕ(N)?
added 222 characters in body
Dec
17
answered Can the encryption exponent e be greater than ϕ(N)?
Dec
17
comment Contruct a protocol to determine if three secret keys are different, without revealing any of them?
@ampersand I think it's not possible to do this strictly sequentially (i.e. last person to go announces results) without some sort of secret blinding, as anyone could interrupt the protocol and decide if the keys of all parties that have gone so far are different, ignoring the remaining parties. This would require the first person to blind the computation, and be given the final computation to announce the result. I am confident it can be done without leaking any secret keys, but it's not very clean..
Dec
17
comment Cracking WWII-era codes - code found on a pigeon's leg in Surrey
Some things are "uncrackable" even with infinite computing power.
Dec
16
comment Is there a big RSA Data Set
If you meant a list of all possible keypairs, this may help put things into perspective (by the way, saving $d$ is unnecessary if you already know $p$ and $q$ as it can be efficiently calculated from $e$).