curious

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	523 reputation	bio	website		visits	member for	1 year, 5 months
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Apr 29	asked	Secure order preserving hash function
Apr 28	comment	Indistinguishability CPA and CCA2 it would be very helpful to explain your downvotes.
Apr 28	revised	Indistinguishability CPA and CCA2 added 84 characters in body
Apr 26	answered	Indistinguishability CPA and CCA2
Apr 21	comment	How strong is the ECDSA algorithm? Since supersingular curves are vulnerable to some attacks(MOV) why people still use them?
Apr 21	comment	Why would anyone use an elliptic curve with a cofactor > 1? then why we do care about even characteristic curves that imply even number of points since they are not secure?
Apr 19	comment	How does order-preserving encryption work? That approach is not secure if the same key is being used for all values. Suppose $c_1=OPE(a)=a+x$ and $c_2=OPE(b)=b+x$. Then the attacker obtains k=c2-c1 = a-b. So he knows that $a$ will in a range $[a-b,OPE(a)]$ . If $X$ is not big enough then the attacker with brute force can try all values in the range.
Apr 15	comment	Recovering SHA1 knowing 2/3 of the hash generated What is the today safe $n$ that make it impossible for an attacker to brute force in a "reasonable" time?Something greater than $80$ ?
Apr 12	accepted	Why unit vectors should be encrypted bit per bit in that case?
Apr 11	revised	Why unit vectors should be encrypted bit per bit in that case? deleted 1 characters in body
Apr 11	revised	Why unit vectors should be encrypted bit per bit in that case? added 90 characters in body
Apr 11	comment	How to implement order preserving encryption or order preserving hashing I looked at the code and still it gets very complex when it comes in OPE. What they do is that they choose random numbers from a distribution and then they check for the order?Or this is the naive approach?
Apr 11	asked	Why unit vectors should be encrypted bit per bit in that case?
Apr 11	comment	Verify product without revealing multipliers @PulpSpy I mean that if you can observe whether or not two ciphertexts came from same plaintext encrypted with ELGamal then this leaks some info and cannot be treated as semantically secure. Or i am wrong?
Apr 11	comment	Verify product without revealing multipliers @PulpSpy "If they are the same, $d$ will be $1$ " , that implies a deterministic scheme with no randomness. Is that the case with the participants when choosing different keys?
Mar 22	comment	How to compute the dot product on encrypted values? It's stupid what i said. Of course itis because $(a + b) \cdot c = a \cdot c +b \cdot c$
Mar 22	comment	Can Elgamal be made additively homomorphic and how could it be used for E-voting? Can i use elgamal for both additions and multiplication of ciphertexts?I.e: Whenever i want to multiply i compute my message $x$ as $g^x$ and whenever i want to add i compute conventional Elgamal. My plaintext would be small integers in a range of $0 \ldots 2^{32} or 2^{64}$
Mar 22	comment	How to compute the dot product on encrypted values? That is is the other way around i think. Instead of $a_1 \cdot b_1 + a_2 \cdot b_2 +a_3 \cdot b_3 +\ldots+ a_n \cdot b_n$ i need $(a_1+b_1) \cdot c_1 + (a_2+b_2) \cdot c_2 + \ldots + (a_n+b_n) \cdot c_n$
Mar 22	comment	How to compute the dot product on encrypted values? Can i obtain the encryption of $E(x \cdot y)$ where $y=E(a)+E(b)=E(a+b)$ and x is $E(x)$ from the aforementioned scheme?
Mar 22	comment	How to compute the dot product on encrypted values? Thank now it's clear to me. I thought as i commented to @Ricky that you can only do one multiplication. Your clarification was very helpful. You can do as many multiplications you want and you only can add them.