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Sep
10
comment Quantum key exchange skepticism/confusion
I believe there are more efficient methods than parity checking, although the only thing I know of that I think is more efficient is fuzzy extractors, which could be used to but do not automatically estimate an upper bound on who much Eve could have seen. $\;$
Sep
10
comment Quantum key exchange skepticism/confusion
I believe the parts of the process can be conducted in parallel (i.e., the parties don't have to do any checking in-between using the quantum channel), but otherwise "you keep exchanging the key over and over until Eve most likely hasn't seen too much of it" sounds basically correct. $\;$
Sep
10
comment Quantum key exchange skepticism/confusion
"if t>n/2 then doesn't" what "not make sense"? $\:$ If you answer is "the whole article", then my response is, "No, it doesn't not make sense, even when t>n/2.". $\:$ Pretty much. $\;\;\;\;$
Sep
10
comment Quantum key exchange skepticism/confusion
No. $\:$ My understanding is that if Eve measures a significant fraction of the quanta, then the parties will detect that with overwhelming probability. $\:$ Even if Eve knew most of the key, the leftover hash lemma would still work in this context. $\:$ You may have heard of the half threshold in the context of non-malleable extractors or general privacy amplification. $\;\;\;\;$
Sep
10
comment How can I map arbitrary group elements to unique integers without using Hash functions?
You would use bit padding so that padded group elements all have the same length, let $p$ be bigger than 2 to that length, and map each group element to the integer represented by the result of padding the group element. $\;$
Sep
10
comment How can I map arbitrary group elements to unique integers without using Hash functions?
@Holmes.Sherlock : $\:$ Yes, since it would let $p$ be bigger than all of the group elements. $\;\;\;\;$
Sep
10
comment How can I map arbitrary group elements to unique integers without using Hash functions?
Why does the ring's ($Z_p$'s) size need to be the same as $G$'s? $\;$
Sep
10
comment How can I map arbitrary group elements to unique integers without using Hash functions?
If you can find a non-identity element and efficiently compute discrete logarithms, then you can use Dennis's suggestion. $\:$ If $S$ is determined before (or independently of) the map, then you can just use a universal hash family. $\:$ If neither of those hold, then I'm pretty sure it depends on the group $G$. $\;\;\;\;$
Sep
10
comment Quantum key exchange skepticism/confusion
Something out-of-scope is to guarantee authentication or message integrity for the classical channel, and nothing is to guarantee authentication or message integrity for the quantum channel. $\:$ It is 50/50 whether or not Eve guesses the correct filter also. $\:$ Due to the leftover hash lemma, Eve can't "see about half the key without Alice or Bob even knowing". $\:$ What is a "proposition of discrepancies"? $\;\;\;\;$
Sep
9
revised How can I map arbitrary group elements to unique integers without using Hash functions?
fixed title's grammar
Sep
9
comment “Practical” operations supported by functional encryption?
Note that there is a qualitative difference what homomorphic encryption does and what the other two types you mentioned do. $\:$ The results produced by homomorphic encryption are still encrypted, and one might plausibly expect the schemes to be IND-CCA1. $\:$ The results produced by the other two schemes are in-the-clear, so semantic security cannot hold. $\:$ I another type of scheme in which the private key holder can issue tokens that suffice for in-the-clear results for specific functions, although I don't remember what those papers were or whether the schemes were practical. $\;\;\;\;$
Sep
9
comment Privacy-Preserving Protocols and Proofs of Security
Where have you seen "the argument" "that, because c does not follow a perfect uniform distribution (assuming x and y do), the protocol is not secure."? $\;$
Sep
9
asked Is there a practical succinct interactive argument for fortress draws in chess endgames?
Sep
8
comment Are there valid attacks on full SHA-1?
@user220201 : $\;\;\;$ In what sense does AES provide "80 bit security"? $\:$ Is it the same as the sense in which AES also provides n bit security, for all values of n smaller than 80? $\;\;\;\;\;\;\;$
Sep
7
comment Why does FIPS 186-4 require specific sizes for keys?
verifies $\mapsto$ verifiers $\;$
Sep
6
revised Why does FIPS 186-4 require specific sizes for keys?
improved grammar
Sep
5
revised Privacy-Preserving relational databases: checking the existence of a record (or multiple records)
addressed the issue of list-queries
Sep
4
revised Privacy-Preserving relational databases: checking the existence of a record (or multiple records)
changed "lists" to "sets"
Sep
4
comment Hard problems in composite order group even when factorization is known
There is no known proof for any of them. $\;$
Sep
4
comment Hard problems in composite order group even when factorization is known
I'm pretty sure all of these remain intractable in groups whose order is a composite with a known factorization. $\;$