Can a static object be fully-cached for HTTPS? (encrypted)

Question

If I have a static object (file), which being requested by clients via HTTPS - is it possible to cache the file after encryption took place? (for the purpose of saving the processing time of encrypting for each and every client upon request)

Note: I'm not asking how to do it, but rather if it's even possible.

Answer 1

No. The encryption keys generated by SSL/TLS will be different for each connection. One component of the key-derivation is a client-generated nonce, so the server has no way of pre-calculating the key.

Answer 2

By sending Cache-Control: public many browsers will cache content even if it is sent over SSL.

IE, and FF3+ should respect this.

EDIT: Sorry misread the question. You can also store content after encryption using some sort of proxy server.