libsecp256k1 create ECDH secret - constant time ECDH calculation
@param seckey byte array of secret key used in exponentiaion @param pubkey byte array of public key used in exponentiaion
libsecp256k1 create ECDH secret - constant time ECDH calculation
@param seckey byte array of secret key used in exponentiaion @param pubkey byte array of public key used in exponentiaion