On Monday, September 11, 2017 at 10:01:41 PM UTC-4, Derek Cole wrote: > > Hello, > > I have been trying to learn ElGamal encryption by way of this site: > > https://cryptographyacademy.com/elgamal/ > > I am able to find the SubgroupOrder, SubgroupGenerator, and Modulus of an > ElGamalKeys::PublicKey, but I am unable to find the 3rd parameter of the > PublicKey which is computed using Alice's private exponent. According to > the site: > > Next Alice chooses the secret key sk=a between 1 and p−1 and computes >> A=g^a mod p >> > Alice then publish the public key pk=(p,g,A). >> > > So how do I find the A parameter from the PublicKey? >
I believe A is a domain parameter. Alice and Bob have to agree to use them before any instance of a protocol is run. The equivalent problem in elliptic curves is, how do you know which field you are working in. That's why you have named curves like NIST P-256. The name P-256 conveys the domain parameters we need to execute an instance of the protocol. My apologies if I mis-parsed the question. Jeff -- -- You received this message because you are subscribed to the "Crypto++ Users" Google Group. To unsubscribe, send an email to cryptopp-users-unsubscr...@googlegroups.com. More information about Crypto++ and this group is available at http://www.cryptopp.com. --- You received this message because you are subscribed to the Google Groups "Crypto++ Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to cryptopp-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
