Recetly while studying about cryptographic primtives, I have come across below line in wiki : http://en.wikipedia.org/wiki/ElGamal_encryption
Encryption under ElGamal requires two exponentiations; however, these exponentiations are independent of the message and can be computed ahead of time if need be.
Does "if need be" in the sentence refering to a static key? or is he saying that we can compute an ephemeral key prior to encryption and send to receiver, then later send the encrypted ciphertext at some other time.
If he is not refering to ephemeral key, I still want to know, are there any times we can really implement such a process using ephemeral.