can you tell me if there are any differences between POP3S and POP3 with STARTTLS?
What's the safest? Are there any known attacks?
If you could choose about them, which would you pick? Thanks a lot
The only difference is that with old-style SSL, it is implied that you will start SSL negotiation immediately upon connection. With STARTTLS, you go through the same process, but only after issuing/receiving a STARTTLS command. The protocols are designed to throw away any information discovered or negotiated before the connection was secured, and start over again from scratch.