The most famous key exchange algorithm with perfect forward-secrecy.
2
votes
1answer
317 views
Generalizing the conversion of Diffie-Hellman to El Gamal
How can we generalize the conversion of Diffie-Hellman to El Gamal public-key encryption scheme? The goals is to be eventually able to show that any 2-round key-exchange protocol can be converted into ...
3
votes
1answer
108 views
Is there a group of prime order which could fit the CT-Computational Diffie-Hellman assumption?
I'm trying to choose a group that is hard under the Chosen-Target Computational Diffie-Hellman assumption, according to the definition in this paper, in order to implement the oblivious transfer ...
7
votes
3answers
3k views
How does one calculate a primitive root for Diffie-Hellman?
In the Diffie-Hellman key exchange, one of the steps involves calculating a primitive root of a prime number $p$. How would one go about doing so, considering that $p$ could be very large?
Is there ...
20
votes
1answer
1k views
Does the generator size matter in Diffie-Hellman?
For the Diffie-Hellman protocol I've heard that the generator 3 is as safe as any other generator. Yet, 32-bit or 256-bit exponents are sometimes used as generators. What is the benefit of using ...
4
votes
2answers
764 views
How to calculate the time it'll take to crack RSA or DH?
Sometimes the easiest way to describe security of a type of cryptography is to say that "the time it takes to solve for an x-bit key would be y years". How would one go about doing such a calculation ...
5
votes
2answers
816 views
Why can't Diffie-Hellman be used for signing?
I understand that signing is often a case of hashing data and then encrypting the hash with the private key. What properties keep Diffie-Hellman from being useful for this?
11
votes
3answers
1k views
For Diffie-Hellman, must g be a generator?
Due to a number of recently asked questions about Diffie-Hellman, I was thinking this morning: must $g$ in Diffie-Hellman be a generator?
Recall the mathematics of Diffie-Hellman:
Given public ...
