pbsd

78 ms·

691.
by pbsd 14y ago
Does Go only support that crazy Plan 9 (amd64) assembler syntax that nobody uses anywhere?
692.
by pbsd 14y ago
While Mersenne primes make breaking discrete logs easier over prime fields, they're pretty OK to use as underlying field on elliptic curve groups (cf. p521).
693.
by pbsd 14y ago
C11 adds thread and atomic op support: https://en.wikipedia.org/wiki/C11_%28C_standard_revision%29
694.
by pbsd 14y ago
To make license keys unforgeable, you have to go public key. Typically some sort of digital signature. This won't make your application uncrackable, but will make it impossible to fake legit licenses. A good reference on how to get these th
695.
by pbsd 14y ago
Great response, thanks; I had not even considered the d=3 possibility. I'd just like to say in my defense that mentioning OAEP wasn't assuming the application was encryption: it was simply the first provably secure padding that came to mind
696.
by pbsd 14y ago
What kind of attacks remain when using proper padding (e.g. OAEP)?
697.
by pbsd 14y ago
e=3 is fine, so long as you remember to pad...
698.
by pbsd 14y ago
I suppose he wanted to showcase boost::format. You can do it simpler with std::to_string: return to_string(static_cast<unsigned char>(s[0]));
699.
by pbsd 14y ago
Käsper and Schwabe's bitsliced AES [1] does not need very long streams to be fast. It processes 8 blocks simultaneously, not 128 (as a 'pure' bitsliced approach would), and therefore reaches peak performance at relatively small lengths, sta
700.
by pbsd 14y ago
You might want to look at the non-generic implementations, like http://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/x86_...
701.
by pbsd 14y ago
A 512-bit hash provides roughly 256 bits of resistance against collision attacks. We (presumably) want to match that level of strength with our signature scheme. RSA and DSA are based on the integer factorization and finite field discrete l
702.
by pbsd 14y ago
You can hedge your bets with hash combiners: http://homepages.cwi.nl/~pietrzak/publications/FLP08.pdf C_{4P}(SHA-2-512, SHA-3-512) should remain solid for a long long time. Your point of failure is, now, the signature scheme. To last for
703.
by pbsd 14y ago
Fully homomorphic encryption reduces the communication necessary for MPC to a minimum. Since FHE is, at the moment, way too slow to be useful, work has gone in the direction of mixing classic techniques with somewhat homomorphic encryption,
704.
by pbsd 14y ago
Does Schneier really recommend Serpent to avoid XSL-type attacks? As far as I remember, XSL also applied to Serpent.
705.
by pbsd 14y ago
It's pretty quick to generate a lot of collisions, and the set of inputs you get will collide independently of the seed. Look (CityHash64): $ time ./citycollisions 1000000 > /dev/null real 0m0.904s user 0m0.439s sys 0m0.008s $
706.
by pbsd 14y ago
Not really. The SipHash page contains proof-of-concept code that breaks common good non-cryptographic randomized hashes, i.e., it generates collisions regardless of the chosen seed. Regarding performance, SipHash is essentially as fast as
707.
by pbsd 14y ago
The permutations in DES have nothing to do with security; there is an excellent explanation by Thomas Pornin on what their purpose was: http://crypto.stackexchange.com/a/6/592 What was altered were the 8 S-boxes, seemingly random lookup t
708.
by pbsd 14y ago
1 - Very slow 2 - A nightmare to implement securely 3 - Only exists for the sake of provable security 4 - The same standard defines a much better alternative pseudorandom generators based on hashes and/or block ciphers.
709.
by pbsd 14y ago
No. The backdoor relies on the generator of the parameters (presumably the NSA) knowing a discrete logarithm ahead of time. Anyone outside the NSA would have to break a rather large discrete logarithm, which is just not gonna happen anytime
710.
by pbsd 14y ago
Not all KDFs need to be slow, but only those that take as input a low-entropy secret (e.g., a password).
711.
by pbsd 14y ago
They're not comparable: PBKDF2 is a mode of operation, bcrypt is an actual instantiation of a password hashing scheme. Saying one is (objectively) better than the other is meaningless, or at least very misleading.
712.
by pbsd 14y ago
There is little point in concerning oneself with smooth p-1, p+1, Φ_i(p) values. Randomly-chosen primes will have a negligible chance of having such properties. Additionally, the more powerful ECM algorithm can be parametrized to generate a
713.
by pbsd 14y ago
There is no obvious implication of the abc conjecture to cryptography.
714.
by pbsd 14y ago
Overly complex C++11: http://ideone.com/yHzej The output assembly is actually pretty good (std::vector specialization): ; prologue L19: add eax, esi cmp ebx, eax je L4 L8: mov ecx, DWORD PTR [eax] cmp ecx, DWORD PTR
715.
by pbsd 14y ago
This is just a nitpick, but why is SRP (Wu) in your list? Looks a bit out of place there.
716.
by pbsd 14y ago
Photos capture pixels. You get attached to it, like some people get attached to other inanimate objects (trinkets, lockets, and so on). It seems hard to believe people need these things to summon memories, but to each his own, I guess.
717.
by pbsd 14y ago
The photo sharing was an addition to the point, and not really thinking of privacy. Who takes pictures, only to keep them to themselves? Seems even more nonsensical. I guess it may be useful to aging people with poor memories?
718.
by pbsd 14y ago
What is there to explain? Why the heck would anyone want to remember all the details of their lives? Worse, have them around for anyone to see (e.g. Facebook and friends). I am unable to imagine some motivation for people wanting this.
719.
by pbsd 14y ago
Oh, I misunderstood. Thought it the point was to make it bitwise. In that case, it is very architecture-dependent. In x86, you can use TEST coupled with SETcc or CMOV for microarchitectures where branch mispredictions are very costly (P4 co
720.
by pbsd 14y ago
> I wonder what the fastest way to negate (boolean-wise) a value other than a bool would be. Maybe you just do a test and then set the value based on a xor of the zero flag. Probably "NOT reg". Exists in most CPU architectures, and is g

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