[Cederfjard]

No. The symmetric key that is used to encrypt the message is itself encrypted once for every recipient with their respective public keys, so the only difference is filesize (for most intents and purposes negligable). Of course, more recipients equals more targets for an attacker.

[bmm6o]

> Of course, more recipients equals more targets for an attacker.

This is especially significant if the recipients have different sized public keys. If you send a message to a 2048-bit key and a 1024-bit key, the message only has 1024 bits of security. So you really do get a weakest link effect.