R and S are the two signature elements. A is the public key, B is the common base. That is, A = B^a in prime fields, or A = a * B on elliptic curves. R is a ran

R and S are the two signature elements. A is the public key, B is the common base. That is, A = B^a in prime fields, or A = a * B on elliptic curves. R is a random element used for each signature, usually R = k * B for randomly generated k. Note that those equations are only covering the verification part of the scheme.