Mike Carpenter
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 Oct 23 awarded Supporter Oct 23 accepted How to prove knowledge of discrete logarithm in a product? Oct 23 comment How to prove knowledge of discrete logarithm in a product? One commitment is $g^{x}h^{r}$ and the other is, for the same $g$, $h$, and $r$, $g^{\prod^{m}_{j=1}{p_{j}}}h^{\nu}$ which is the same as $g^{\mu x}h^{\mu r}$. The two commitments are not necessarily equal to one another. Oct 23 comment How to prove knowledge of discrete logarithm in a product? Thanks for your help and I apologize for being a bit thick. So what are the two Schnorr proofs I should use? The paper I'm working from says I only need two, and it's important that I work as close as possible to get proper timings. Just $\log_{g^{\prime}}h^{\prime}$ and $\log_{h^{\prime}}g^{\prime}$? I actually have another commitment from a previous step $C_{0}=g^{x}h^{r}$, this is about $\mu$ and $\nu$. I really wish the paper were more specific about how it applied its proofs... Oct 23 comment How to prove knowledge of discrete logarithm in a product? So basically if I've already proven knowledge of $x$ and $r$ in a previous step, I just need to prove $g^{\prime\mu}$ and $h^{\prime\mu}$? Oct 22 asked How to prove knowledge of discrete logarithm in a product? Oct 21 asked How to prove that a commitment hides the decryption of an ElGamal ciphertext? Sep 24 accepted Number generation for Fujisaki-Okamoto commitment scheme parameters Sep 24 comment Number generation for Fujisaki-Okamoto commitment scheme parameters I am sure I can find a way to do so. Since that is outside the scope of the original question, which you answered wonderfully, I'll do my own research on that. I don't expect it should be as difficult to find information as this was, since it is much more general! Sep 24 comment Number generation for Fujisaki-Okamoto commitment scheme parameters I am using Java, and generating primes with BigInteger.probablePrime(int bitLength, Random rnd) and a SecureRandom for the RNG. I am willing to generate $p$ and $q$ as safe-primes, especially if it makes it easier, but I'm unaware of any method to ensure it is a safe prime other than generating primes at random and checking that they are safe primes or Sophie Germain primes. I assume there is a more reliable method? Sep 24 awarded Editor Sep 24 revised Number generation for Fujisaki-Okamoto commitment scheme parameters added equation for Fujisaki-Okamoto ocmmitment (C=g^x*h^r mod n) Sep 24 asked Number generation for Fujisaki-Okamoto commitment scheme parameters Mar 11 awarded Scholar Mar 11 accepted Can I use asymmetric encryption for more powerful write-protection? Mar 4 comment Can I use asymmetric encryption for more powerful write-protection? @izaera The database is static and would only ever change in bugfixes or updates, so that key wouldn't be anywhere in the distribution at all. No signing of any file would ever happen on any machine but my own. Mar 4 awarded Student Mar 4 comment Can I use asymmetric encryption for more powerful write-protection? @StephenTouset I don't need to make it literally impossible. If it has to be modified in-memory, that for me is reasonably prohibitively difficult. It's a single-player game, I just don't want to make it so trivial to cheat that editing a database file is sufficient, which far more people are capable of or willing to do than edit in-memory. Mar 4 asked Can I use asymmetric encryption for more powerful write-protection?