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Nov
30
comment paradox on fully homomorphic equality checking
"does not the result"? ​ (You seem to be missing a verb.) ​ There's certainly no obvious way of using FHE to let the ciphertext-holder non-interactively check equality. ​ ​ ​ ​
Nov
30
comment paradox on fully homomorphic equality checking
1. ​ The server will use the FHness of the encryption scheme. ​ ​ ​ 3. ​ No ​ ​ ​ ​ ​ ​ ​ ​
Nov
24
comment Miller Rabin - Error probability of .5 a possibility?
Huh, that does confuse me about the algorithm. ​ ​
Nov
24
comment Miller Rabin - Error probability of .5 a possibility?
If u=1 then your initial for loop will execute 0 times. ​ ​
Nov
23
comment Why can you reverse a modulo function when knowing its primes
en.wikipedia.org/wiki/Fermat%27s_little_theorem en.wikipedia.org/wiki/Fundamental_theorem_of_arithmetic ​ ​
Nov
22
revised Is there a way to do single key-pair asymmetric encryption?
fixed grammar and spelling
Nov
21
answered Is it safe to use AES-CBC like this?
Nov
20
comment Keyless integrity checking with SHA-256
@Hans : $\;\;\;$ Because resistance to length extension attack is goal (which hash functions would have to go to a non-zero amount of effort to hopefully achieve) that is not at all relevant to your use case. $\:$ However, using randomized hashing would be good. $\;\;\;\;\;\;\;\;$
Nov
17
revised Why is Tor alone not enough to guarantee anonymity for Bitcoin?
fixed grammar
Nov
17
revised Can the Smart-Vercauteren Homomorphic Encryption be implemented as a practical fully homomorphic encryption scheme?
improved grammar
Nov
16
comment what problem happen if we always use IV Zero in CBC Mode?
@Mahsaehsani : ​ See my previous comment. ​ ​ ​ ​
Nov
16
comment what problem happen if we always use IV Zero in CBC Mode?
@curious : ​ ​ ​ The actual requirement for CBC mode is that the IV be unpredictable. ​ If the IVs are chosen randomly but, after the adversary sees challenge ciphertext's IV, the adversary learns an IV before choosing the corresponding plaintext, then the adversary can check a guess of the challenge plaintext's initial block. ​ On the other hand, (for example) the middle two bits of the IV always being 1 wouldn't be a problem. ​ ​ ​ ​ ​ ​ ​ ​
Nov
14
comment Encryption that can only be decrypted once?
There might also be some way to do it with quantum mechanics. $\;$
Nov
14
comment Simulation Based Proof: How the Corrupted Party's Input is Given To Simulator
That depends on whether your planning on actually implementing it or just giving a theoretical construction. ​ Also, I realize that there was ambiguity in my abbreviations. ​ As I'm using it, the C in CZKAoK stands for Computational. ​ Concurrent ZK is not relevant to your application, since Alice's privacy can be shown by a hybrid argument. ​ ​ ​ ​
Nov
14
comment Simulation Based Proof: How the Corrupted Party's Input is Given To Simulator
@MHSamadani : ​ ​ ​ Yes. ​ Hopefully, you can fit in a ZKPoK of SK. ​ If Bob is only supposed to have computational security, then a CZKAoK would also work. ​ If you can't do either of those, but Bob's security against an honest-but-curious adversary is information-theoretic, then you could probably also get information-theoretic indistinguishability against a malicious Alice with respect to a PSPACE simulator, which is still a non-trivial notion of security. ​ ​ ​ ​ ​ ​ ​ ​
Nov
14
comment If a PRG is constructed by iterating a PRF, is it backtracking-resistant?
Yes. $\:$ en.wikipedia.org/wiki/Advanced_Encryption_Standard $\;\;\;\;$
Nov
14
comment If a PRG is constructed by iterating a PRF, is it backtracking-resistant?
A PRF with large domain is hard to invert for parties/people who don't know the key. ​ ​
Nov
14
comment If a PRG is constructed by iterating a PRF, is it backtracking-resistant?
Yes. ​ Who is a PRF hard to invert for? ​ ​ ​ ​
Nov
13
comment Simulation Based Proof: How the Corrupted Party's Input is Given To Simulator
@MHSamadani : ​ ​ ​ "we need to extract the input of real world adversary" when we need to do something with it (like send it to something/someone), and we don't when we don't. ​ Yes, but it's not relevant here. ​ That depends on the protocol/scheme. ​ "Using a ZKPOK to prove knowing the secret key" would work. ​ ​ ​ ​ ​ ​ ​ ​
Nov
12
comment If PRF is non invertible, why does Ctr-mode work?
For any length, $\: \langle$ binary_strings_of_that_length , xor $\rangle \:$ is an abelian group. $\hspace{1.92 in}$ For any length, each element of that group is its own inverse. $\;\;\;$