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Jun
21
comment Is it possible to perform a rudimentary asymmetric key encryption algorithm by hand?
Digital signatures do not "use asymmetric key encryption". $\:$ They do not even have $\hspace{1.35 in}$ to be based on asymmetric key encryption. $\;\;\;\;$
Jun
21
comment Is it possible to perform a rudimentary asymmetric key encryption algorithm by hand?
That thought would need digital signatures, not asymmetric key encryption. $\;$
Jun
20
comment Ballot box with multiple parties. All can read it, or none can read it
The other problem is that the commitment scheme might be malleable. $\;$
Jun
20
revised Ballot box with multiple parties. All can read it, or none can read it
elaborated on distributed moderators
Jun
20
comment Password-based encrypted key storage?
If the (padded) plaintext is longer than one block, then a MAC would probably $\hspace{1.67 in}$ be useful for the attack scenario I described. $\;$
Jun
20
revised Ballot box with multiple parties. All can read it, or none can read it
increased answer's optimism
Jun
19
comment Ballot box with multiple parties. All can read it, or none can read it
When using the "lots of moderators" option, it would take at least half of the moderators to violate the $\;\;\;$ all-or-none property, not just "one detractor". $\:$ Also, even if that happens, each detracting player can only hide that player's own message from the rest of the players, i.e., the non-detractors' messages still get revealed and still must be independent of each other. $\;\;\;\;$
Jun
19
comment Ballot box with multiple parties. All can read it, or none can read it
I suppose one could try something like that, but I don't see any reason to prefer doing so $\hspace{.92 in}$ over using an actually secure commitment scheme. $\;$
Jun
19
comment Ballot box with multiple parties. All can read it, or none can read it
That doesn't work, since one can just try inputs. $\;$
Jun
19
answered Ballot box with multiple parties. All can read it, or none can read it
Jun
19
answered Password-based encrypted key storage?
Jun
18
comment What are good combinations of public key algorithms or primitives for long term security?
en.wikipedia.org/wiki/McEliece_cryptosystem $\;$
Jun
18
revised Fiat–Shamir: why do r and s have to be smaller than n?
TeXified less-than sign
Jun
18
comment Authenticated encryption without padding
I would be quite surprised if the public random permutation method has to work. $\:$ In particular, although I don't see a way to argue the existence of such schemes, any sufficiently malleable length-preserving encryption scheme would be a counterexample to the claim that the public random permutation version of your option provides "as much integrity as is possible". $\;\;\;\;$
Jun
17
comment Choose a random number that is different from a bunch of other secret numbers
(... continued) $\:$ functionality is performed by a trusted third party then that guarantees choosing a non-clashing number and the adversary has only a half change of learning the honest party's secret number, but if your idea is repeated enough to have a sufficiently large probability of choosing a non-clashing number then the adversary has greater than a 5/6 change of learning the honest party's secret number. $\;\;\;\;$
Jun
17
comment Choose a random number that is different from a bunch of other secret numbers
I mean the "secret number between [0..x]". $\:$ I also notice that the probability I mentioned is not relevant, since an adversary would have a larger probability even if the functionality described in the opening post was performed by a trusted party. $\:$ However, for n=2 and x=3 (the simples non-trivial case), if the adversary's secret number is 2 and the honest party's secret number is either 0 or 1 and the $\:$ (continued ...) $\;\;\;\;$
Jun
17
comment Authenticated encryption without padding
Do you know of any candidate length-preserving AONTs? $\;$
Jun
17
comment Choose a random number that is different from a bunch of other secret numbers
"Proofs that participants are acting honestly is not necessary." - Do you mean adversaries are assumed to be semi-honest, or that simulatability is not required? $\;$
Jun
13
comment How to prove identity without revealing identity
No; I'm not aware of any references for this. $\:$ It's just fairly direct use of a standard signature scheme. $\hspace{.27 in}$
Jun
13
comment Algorithm accepting every passphrase to fool unlegit user
crypto.stackexchange.com/q/2272/991 $\;$