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Apr
1
comment Is computing roots moduli a composite $N$ a hard problem without knowing the factorization of $N$?
@Aleph Then why finding $x \mod N$ from $x^u \mod N$ is difficult? You compute $v=u^{-1}$ and then $x= (x^{u})^v=x^{uu^{-1}} \mod N$
Apr
1
comment Is computing roots moduli a composite $N$ a hard problem without knowing the factorization of $N$?
Does this imply that finding inverses mod $N=pq$ is also hard as long you don't know the factorization of $N$
Mar
31
revised Is computing roots moduli a composite $N$ a hard problem without knowing the factorization of $N$?
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Mar
31
comment Is computing roots moduli a composite $N$ a hard problem without knowing the factorization of $N$?
The adversary knows $N^2$, so i guess it is not hard to learn the inverse of $u$ with the extended Euclidean.
Mar
31
comment Is computing roots moduli a composite $N$ a hard problem without knowing the factorization of $N$?
Yes but my concern is that i want the inverse not moduli $\phi(N^2)$ but $(N^2)$
Mar
31
comment Is computing roots moduli a composite $N$ a hard problem without knowing the factorization of $N$?
The solution to the RSA problem as you said is the inverse of $e$ moduli $\phi(N)=(p-1)(q-1)$. And it is believed that if the factorization $(p,q)$ is not known you cannot find the inverse.
Mar
31
comment Is computing roots moduli a composite $N$ a hard problem without knowing the factorization of $N$?
RSA problem states that it is difficult to compute multiplicative inverses moduli $\phi(N)$
Mar
31
revised Is computing roots moduli a composite $N$ a hard problem without knowing the factorization of $N$?
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Mar
31
revised Is computing roots moduli a composite $N$ a hard problem without knowing the factorization of $N$?
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Mar
31
revised Is computing roots moduli a composite $N$ a hard problem without knowing the factorization of $N$?
edited body
Mar
31
asked Is computing roots moduli a composite $N$ a hard problem without knowing the factorization of $N$?
Mar
3
awarded  Famous Question
Feb
26
revised Are there any asymmetric composite order group bilinear pairings?
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Feb
26
asked Are there any asymmetric composite order group bilinear pairings?
Jan
26
awarded  Tumbleweed
Jan
19
asked Differential Privacy and appropriate noise distribution
Dec
28
comment Why is proof-by-reduction needed (for Elgamal proof of security, for example)?
@Maeher i can't get how you start building your distinguisher since you state:compute x. In order to compute x you break DL, which is impossible for computationally bounded adversary.
Dec
18
awarded  Popular Question
Dec
15
accepted What is the difference between uniformly and at random in crypto definitions?
Dec
15
asked What is the difference between uniformly and at random in crypto definitions?