Felipe Alvarez schrieb: > On Thu, Mar 26, 2009 at 8:17 PM, Sven Radde <em...@sven-radde.de> wrote: > >> Hi! >> >> Felipe Alvarez schrieb: >> >>> Someone today shook my understanding of asymmetric ciphers. >>> >>> _Bob performs symmetric encryption on message with_ >>> _key "K" (generated randomly). He then encrypts "K" _ >>> _with Alice's public key, and sends both the symetrically _ >>> _encrypted message and asymmetrically encrypted key to Alice_ >>> >>> Is this what happens during most/some/all of public-key >>> communications? >>> >> Yes. It's called a "hybrid cryptosystem" and is exactly what is done in >> virtually all practical implementations (SSL, OpenPGP, ...). >> The main reason is that asymmetric operations are hugely inefficient so >> that you do not want to encrypt 1GB of data with RSA. >> >> Another reason: "K" could be separately encrypted with Alice's, Bob's >> and Carol's key which allows several recipients for an encrypted message >> without having to encrypt the message itself several times I think the latter is the more important point nowadays. I do not believe doing complete RSA encryption would take too long on modern hardware for reasonable file sizes. But if you encrypted a file of 10MB to 10 recipients this way, it would become around 100MB in size. > I learned a lot thanks for explaining it so quickly and easily. I had > thought that the entire message was encrypted with (say) RSA! Is there > a way to "force" gpg to encrypt an entire message with (example) RSA > (just for time-testing purposes?) > Felipe No, I don't think that's possible.
Bye, Andreas _______________________________________________ Gnupg-users mailing list Gnupg-users@gnupg.org http://lists.gnupg.org/mailman/listinfo/gnupg-users
