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Jul
3
answered How broken is a xor of two multiply with carry generators?
Jul
3
comment How broken is a xor of two multiply with carry generators?
3. The question is not well-defined. There are many variants of MWC generators. The security of the scheme might depend upon what variant you choose and what parameters you choose (e.g., the lag, the base, the multiplier, the initial carry). Can you provide a complete specification of your proposed scheme with all parameters specified? What size is the seed for each MWC generator?
Jul
3
comment How broken is a xor of two multiply with carry generators?
1. Can you provide any motivation for this question? Why should we care? I could generate endless number of variants of a question that take the form "Consider the following rather-dubious PRNG that's probably not secure and hopefully no one uses; just how badly broken is it?", but I don't know if that'd be useful to the world at large. 2. What research have you done? What effort have you made? What is the best attack you can find on this cipher? We expect you to make a significant effort before asking here, and to show us what research/attempts you've made.
Jul
3
comment I hashed my bag and in it I put… “Is there a hash for unordered items?”
In addition to the excellent answer below based on Merkle hash trees, you can also take a look at crypto.stackexchange.com/q/11420/351 and crypto.stackexchange.com/q/6497/351 and crypto.stackexchange.com/a/489/351 (H(sort(H(x),H(y),..))) and crypto.stackexchange.com/q/17935/351.
Jul
3
comment I hashed my bag and in it I put… “Is there a hash for unordered items?”
possible duplicate of Hash of multiset of values, which lets me compute the hash of the union
Jun
29
comment What is a “lattice” in cryptography?
What research/self-study have you done? We expect you to do some research on your own before asking. See crypto.stackexchange.com/help/how-to-ask. Your question is covered in many standard places, e.g., textbooks and Wikipedia. If your question is answered in the obvious place on Wikipedia, you probably haven't done enough research before asking.
Jun
22
awarded  Constituent
Jun
22
awarded  Caucus
Jun
22
comment Which symmetric cipher is best for studying?
Study, for what purposes? What are your study goals? What do you want to learn? This will greatly affect the answer. (Also, you seem to have an implicit premise that the best way to learn whatever it is you want to learn is by devoting your time to studying a single modern symmetric cipher. I think there's a good chance that premise is not accurate.)
Jun
17
answered Brute-force attack given multiple hash prefixes
Jun
17
comment Brute-force attack given multiple hash prefixes
There's no "big question" here. SHA-1 is almost certainly such a function -- if it wasn't, it would be horribly broken, and we probably would have noticed this deviation from random from now. So from the perspective of an attacker, yes, an attack can absolutely treat SHA-1 in this way. As a result, the bottom line is: 2 candidates are enough to filter down to the true secret. Universal hash functions are a distraction, and the last paragraph introduces uncertainty that doesn't really exist in practice.
Jun
7
revised Is randomsound for increasing entropy pool not doing what it is supposed to do?
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Jun
7
comment Creating a LCG with m = 32767
I'm voting to close this question as off-topic because it's not about cryptography. Non-cryptographic PRNGs are off-topic here.
Jun
7
comment Is it possible to choose which point will have the public key of a given Elliptic Curve?
What are you free to choose? Are you free to choose the generator? The definition of the curve? (i.e., the equation defining the curve) Or are those fixed? Please edit your question to clarify -- as it stands it can't be answered definitively, as the answer depends on those constraints.
Jun
4
comment How do we know a cryptographic primitive won't fail suddenly?
You can't be sure. You can't be sure any of them are secure, and you can't be sure you'll have advance warning of a break. See What's the mathematical model behind the security claims of symmetric ciphers and digest algorithms? and How to prove the security of the PRNG? for more.
May
20
answered Severity of Cooking NIST P Curve Constants
May
18
comment Is what i'm trying to do safe?
@VincentAdvocaat, what I meant was that you didn't mention you had tried specifically TLS with pre-shared keys....
May
17
comment Is what i'm trying to do safe?
@VincentAdvocaat, then you should mention that in the question. We expect you to tell us what you've considered and what you've tried in the question. No one likes taking the time to write an answer and then have the original poster come back and say "I already knew of that".
May
15
comment Is what i'm trying to do safe?
@SOJPM, pre-shared keys for TLS seem like a counterexample to the claim that TLS handshakes always require asymmetric crypto -- no?
May
15
revised Is what i'm trying to do safe?
added 108 characters in body