Barack Obama

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visits member for 1 year, 6 months
seen 9 hours ago

May
7
answered RSA leak bits to factor N
May
7
answered Solving a discrete logarithm using GDlog
Apr
29
comment Adding and multiplication in jacobian coordinates
This is the relevant page of the Explicit-Formulas Database (thanks @CodesInChaos)
Apr
13
comment ElGamal: Generation of “g” value?
I have experienced people being quite negative about efficiency gains from having $g=2$. I haven't investigated so I have no opinion. Also, I found abc's answer to this post which would lead people (wrongly) to believe that $g=2$ is insecure for signatures in all cases. Perhaps you may care to leave a comment on the linked question to set the record straight for posterity. You have the gravitas I do not.. (yet!)
Apr
13
comment ElGamal: Generation of “g” value?
However, if you look at Appendix A.2 of FIPS 186-3 (the Digital Signature Standard) you will find a more comprehensive treatment of similar issues which boils down to pretty much the same thing.
Apr
12
comment ElGamal: Generation of “g” value?
If your maths knowledge is such that you can't see the truth of this when it's pointed out to you then the best solution is for you to brush up on your maths rather than for me to find someone who agrees with me.
Apr
12
revised ElGamal: Generation of “g” value?
fixed obvious typo and added link
Apr
12
suggested suggested edit on ElGamal: Generation of “g” value?
Apr
12
answered ElGamal: Generation of “g” value?
Apr
9
comment ECKS-PS algorithm: searching in encrypted data; bilinear maps
Looking through your first page of notes (which I don't find easy to read) I notice that you appear to have e(i,j)=53^(i*j) mod 59 where I would normally read e to be some suitable paring computation on an elliptic curve. I presume you believe you're allowed to make this substitution to make thing simpler but it's not clear to me that it's actually going to work. Is this something you can justify?
Feb
10
revised Request for 1024-bit primes $p$ , subgroup $q$ and subgroup generator $g$
more specific answer based on questioners comments
Feb
10
revised Request for 1024-bit primes $p$ , subgroup $q$ and subgroup generator $g$
added info from author comment
Feb
10
suggested suggested edit on Request for 1024-bit primes $p$ , subgroup $q$ and subgroup generator $g$
Feb
10
suggested suggested edit on Request for 1024-bit primes $p$ , subgroup $q$ and subgroup generator $g$
Feb
7
comment Is such a crypto-system available?
@poncho Good answer BTW! You say that with my solution, if Eve and Bob collude then they can read the entire text. I can't work out what assumptions you must be making for this to be true, but yet for the scheme not to be rejected outright due to the absence of a selective disclosure property. In other words, how must the system be set up for collusion to be of any benefit?
Feb
3
answered Why do the elliptic curves recommended by NIST use 521 bits rather than 512?
Feb
3
answered Trapdoor implementation
Feb
2
answered Why would this method of discrete logarithm finding not work?
Jan
31
awarded  Teacher
Jan
31
awarded  Editor