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May
30
comment What is the difference between uniformly and at random in crypto definitions?
Seems like uniformity has to do with which elements and randomness how to chose
May
21
comment Given $g^a, g^b, g^c, g^{1/b}$, is it hard to distinguish $e(g, g)^{abc}$ from a random value?
@cygnusv report link does not work
May
12
comment Possible to check if $a \in \mathrm{QR}_n$?
@DrLecter But since the adversary knows that $Jacobi(a)=1$ it means that there exists for sure $y$ such that $y^2=x \mod n$. So adversary can decide whethera has QR since it known that $a \in \{\mathbb{J}=1\}$
May
11
awarded  Promoter
May
5
comment How to calculate if probability is negligible or not
It's weird that the sum of one nn and on n probability is nn while for this for the product does not hold.
May
5
comment security proof in pairing based cryptography
@FlorianBourse even if there is a correlation in $C_x-C_i$, still you have to recover D
May
5
comment security proof in pairing based cryptography
It is more than straightforward i think following the reductionist approach
May
5
answered security proof in pairing based cryptography
May
5
comment security proof in pairing based cryptography
what is $C_x$? Of course if you know $C_x$.What is known to the attacker?What is public and secret?
Apr
27
comment Paillier cryptosystem preserve ordering of sums for two integer sequences
@Alexandros The great about Paillier cryptosystem is the fact that users can encrypt with different randomness under the same public key that will decrypt to the correct plaintext under the single decryption key because $r^{N\lambda}=1 , \forall r \in \mathbb{Z}_{N^*}$
Apr
23
revised what is number of invertible matrix m*m on$ z_n$?
Bad notation and syntax
Apr
16
revised What is a Key Derivation Function?
added 82 characters in body
Apr
16
revised What is a Key Derivation Function?
added 82 characters in body
Apr
16
answered What is a Key Derivation Function?
Apr
8
comment Altering the message space of Paillier
@FlorianBourse this can be done by any homomorphic scheme since they are not supposed to be CCA secure. Meaning, the adversary can alter on its will the ciphertext
Apr
8
accepted Altering the message space of Paillier
Apr
7
asked Altering the message space of Paillier
Apr
7
comment Fault-based transition for crypto proof (a la Shoup) with big probability of fault - does it work?
Well, the assumption is that as long the fault event does not happen then adversary cannot identify that the simulator cheats by not giving her the true transcripts of the original game. This event F is often of this form: [F: A breaks a problem as DDH, CDH, DL, etc] I cannot get why you want to make an assumption that this even happens not negligibly since if this is the case then everything is broken....
Apr
1
comment Is computing roots moduli a composite $N$ a hard problem without knowing the factorization of $N$?
@Thomas you mean that you can find the inverse moduli $N$ but you do not which one is the correct one.
Apr
1
accepted Is computing roots moduli a composite $N$ a hard problem without knowing the factorization of $N$?