3
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What is a secure, modern, partially homomorphic encryption scheme?
ElGamal and RSA «are considered generally insecure» IF one assumes Cryptographically Relevant Quantum Computers. But these remain highly hypothetical. The world (internet, banking, mobile..) currently ...
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3
votes
What is a secure, modern, partially homomorphic encryption scheme?
There are two obvious things to mention.
First, with the caveat that I only briefly skimmed the paper you linked, I see section 3 state that the encryption scheme used needs 3 properties, namely
...
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3
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Is there a mental poker algorithm that does not rely on commutative encryption?
Yes, there are some other algorithms that do not rely on commutative encryption.
The Wikipedia page for Mental poker lists some other examples. It describes a non-shuffling poker protocol that uses ...
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2
votes
Can elliptic curve groups be used for commutative encryption?
This works, as long as the 52 points are chosen such that their discrete logs w.r.t. each other are unknowable.
E.g. if $5♠$ is point $P$, and $6♦$ is point $Q$, and your encryption scalar is $x$, ...
- 4,732
2
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Is there a cryptographic way (a la mental poker) two people can determine if they both Like each other, without revealing their personal preferences?
You were on the right track with Yao's Millionaires Problem. Yao's Millionaires Problem is just one specific example, but almost anything can be calculated securely by using by a garbled circuit.
@...
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2
votes
Would this mental poker algorithm work?
Three issues:
It is super slow.
The "Oops, my bad, I need to redraw" is not correct because he can always say that when he gets anything but a king or a queen.
Alice could also probably pretend she ...
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1
vote
Finding a winner in mental poker game
OK
I had asked this unanswered question earlier and now, I think I have an answer (sort of), not really but I think I know where to look for it. We assign each type of card combination a score such ...
- 601
1
vote
Murder Mystery Party
With some assumptions I think you can do this with a simple protocol.
We will break i into two parts: attempt an allocation which may succeed with reasonable liklyhood. And verify it. If ...
- 11.8k
1
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How to play Mental Skull
Assuming that it's sufficient to catch a cheating player after the round is over, this seems trivial to implement using only bit commitments.
Let $\mathsf{Com}$ be a bit commitment scheme.
At the ...
- 6,818
1
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Faster Shuffling for a Simple Application
The obvious way is to use two oblivious transfers. In case you need reminding: an Oblivious Transfer is a protocol where one party (Alice) has a number of secrets (in this case, two), and the other ...
- 147k
1
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Accepted
Isn't Socialist Millionaires vulnerable if Alice's and Bob's message are picked from a shared list?
The attack you are referring to is called an offline dictionary attack, which checks all possible values against a given transcript. However, the typical security notion for the socialist millionaires ...
- 20k
1
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Is there a cryptographic way (a la mental poker) two people can determine if they both Like each other, without revealing their personal preferences?
The answer to your specific scenario is no, it cannot be done. As mentioned in a comment, if Bob knows his preference (B->A) and learns that the result of the calculation is $0$, then Bob now knows ...
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