Much slower than other block cipher implementations?

[Will Bryant]

Hi all,

My understanding is that when you encrypt a file using GPG a random session key gets generated, that gets encrypted using public key crypto, and then that session key is used to encrypt the file using a regular block cipher.

Why then does GPG only encrypt at about 12 MB/s when OpenSSL can encrypt using the same block cipher at over 260 MB/s on the same machine?

Is it just a faster implementation of the block cipher, or is GPG doing something else that slows it down?

I'm using fairly modern Intel CPUs that do have AES instructions, so I was wondering if that was it.

Cheers,
Will