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May
6
awarded  Popular Question
Feb
25
revised understanding forking lemma
fixed grammar
Feb
25
suggested approved edit on understanding forking lemma
Feb
20
comment How to find generator $g$ in a cyclic group?
Oh right, now everything makes sense! So if we have that $h^2 \mod p \neq 1$, then this is at the same time telling us that $h^2$ is a quadratic residue and therefore must be in the subgroup of order $q$. Thanks a lot for you clarification and for having edited your answer.
Feb
20
comment How to find generator $g$ in a cyclic group?
There's something that seems confusing in your answer and I hope you can clarify it. If we select a safe prime $p=2q+1$ and we now want to select a generator $g$ within the subgroup of size $q$, you suggest to take a random value $h$ between $2$ and $p-1$ and then compute $h^{(p-1)/q} \mod p$, which would be the same as computing $h^2 \mod p$. If the result of this is not $1$ this definitely means that $h$ is not a generator of the subgroup of order $2$, but this doesn't necessarily mean that it's a generator of the one of order $q$, we still would have to check that $h^q=1 \mod p$, don't we?
Jul
2
awarded  Curious
Apr
22
revised ElGamal with elliptic curves
Small correction to explain what is "d"
Apr
22
suggested approved edit on ElGamal with elliptic curves
Apr
18
awarded  Yearling
Feb
21
accepted Does Runge phenomenon affect Shamir's secret sharing scheme?
Feb
20
asked Does Runge phenomenon affect Shamir's secret sharing scheme?
Feb
20
comment Homomorphic crypto allowing anonymous yes/no votes?
As for whether the server can simply decrypt each ciphertext individually instead of decrypting the ciphertext containing the overall result of the election, yes, in principle this can happen. But in order to avoid this, e-voting systems usually use what is known as threshold cryptography: the decryption key is shared among a set of trustees, in such a way that only when a certain subset (threshold) of them collaborate, they can decrypt anything.
Feb
20
comment Homomorphic crypto allowing anonymous yes/no votes?
I don't know about the particular case of the Damgård-Jurik e-voting system, but ZKP are generally used in this context not only to make the voter prove that he voted only once, but also to prove that his vote is valid (for example, he only voted "0" or "1").
Jan
24
revised Question Error Correcting Codes
fixed grammar and some spelling mistakes
Jan
24
suggested approved edit on Question Error Correcting Codes
Dec
6
accepted Difference between Pedersen commitment and commitment based on ElGamal
Nov
24
asked Difference between Pedersen commitment and commitment based on ElGamal
Oct
30
accepted What is it meant by a “hybrid argument”?
Oct
24
accepted Decrypting without using the private key
Oct
24
comment Verifying encrypted addition
Yes, but still you're using a homomorphic cryptosystem, otherwise $\frac{c_1 c_2}{c_3}$ wouldn't give you the encryption of $1$, isn't it?