Yup - you got it. Symmetric encryption is *way* faster (that's a technical term :-) than asymmetric. Hence the slower version is used to exchange a random key that is then used to handle the encryption/decryption of the data. Algorithms are implementation dependent but it is common to use 3DES for the symmetric.
-----Original Message----- From: gnupg-users-boun...@gnupg.org [mailto:gnupg-users-boun...@gnupg.org] On Behalf Of Felipe Alvarez Sent: Thursday, March 26, 2009 5:51 AM To: gnupg-users Subject: cloudy understanding of asymmetric cryptography -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 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? I had always thought that the message is encrypted with public key, and decrypted with secret key. I was not aware that key "K" was encrypted with public key, but message encrypted with __symmetric_cipher__. To help my understanding a little futher, if this does not always occur, or does not usually occur, when does it occur (not occur)? Using what ciphers (algorithms)? I was unable to find adequate explanations online. Thanks Felipe -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (GNU/Linux) iEYEARECAAYFAknLT9sACgkQbm5xe/LPYKKywwCfZoz8b5XOW4EoSy+m6r/xIgli rtcAn3Lb3cwzLL036BjOO5259rNhWFW5 =b2iF -----END PGP SIGNATURE----- _______________________________________________ Gnupg-users mailing list Gnupg-users@gnupg.org http://lists.gnupg.org/mailman/listinfo/gnupg-users _______________________________________________ Gnupg-users mailing list Gnupg-users@gnupg.org http://lists.gnupg.org/mailman/listinfo/gnupg-users
