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Oct
1
comment A variant of Shamir secret sharing
The fact that this only works because we are not doing a modulo operation tells me that in practice it really isn't an attack. That is because the only time you won't do a modulo in practice is when all the coefficients are very small and the secret is very small (compared to the modulus).
Oct
1
comment A variant of Shamir secret sharing
@user153465 I think I see what you are saying. Since $2x+3$ becomes $18x+27$, all shares will be a multiple of $9$, so the adversary can figure that the secret is $9$.
Oct
1
comment A variant of Shamir secret sharing
@user153465 your example here assumes that the adversary knows that the constant term of the polynomial is $0$. Like I said in my answer, if the constant term of the polynomial is $0$ (or in this case, knows to be $0$ by the adversary) there is an issue. If the constant term is not necessarily $0$, the adversary does not know which secret the belongs to.
Oct
1
answered A variant of Shamir secret sharing
Oct
1
comment A variant of Shamir secret sharing
Why do you want to use this? Is there any specific reason? In other words, what is your application scenario.
Oct
1
answered Hardness proof?
Oct
1
revised what are DP and DQ in Encryption by RSA in c#
edited body
Oct
1
answered what are DP and DQ in Encryption by RSA in c#
Oct
1
comment Why are we not using multiple ciphers per message?
@Einar, not sure. Don't have the time to read and digest all that at the moment. Could be a useful question to ask on this site (or possibly another SE site).
Oct
1
comment Is Attribute based encryption sub-class of Identity based encryption
To add to what @DrLecter says, given an ABE scheme, you can construct an IBE scheme. You can't go the other way. The way to construct IBE from ABE is to give every participant in the system a single attribute. The attribute value is their identity.
Sep
30
comment Why are we not using multiple ciphers per message?
You can't compute in parallel things that depend on the output of each other.
Sep
30
revised Homomorphic encryption based on XOR
added 118 characters in body
Sep
30
comment Homomorphic encryption based on XOR
@PaŭloEbermann re second comment, for $+$, I was talking about the typical way we do addition in finite fields of characteristic 2.
Sep
30
comment Homomorphic encryption based on XOR
@PaŭloEbermann re first comment, you mean $=(a\oplus b)\neq(a\oplus b)\oplus d$ right? I was more going along the question of the OP "can we derive b+a from any combination of c1 and c2". In this case, we can derive $a\oplus b$ from some combination of c1 and c2.
Sep
30
awarded  Explainer
Sep
30
comment Any weakness when sha256'ing output of sha256, repeatedly?
Another related one
Sep
30
comment Any weakness when sha256'ing output of sha256, repeatedly?
Related question
Sep
30
revised Homomorphic encryption based on XOR
deleted 1 character in body
Sep
30
revised Homomorphic encryption based on XOR
added 429 characters in body
Sep
30
answered Homomorphic encryption based on XOR