private key protection

[Robert J. Hansen]

On 06/25/2012 11:44 AM, Werner Koch wrote:
>> cracking the symmetric encryption used to protect the private key is
>> comparable to the problem of cracking an encrypted message's session
>> key. 
> 
> No, it is not.  The entropy in a session key matches the size of the
> session key.  The key used to protect the private key is commonly much
> weaker.  A passphrase providing an adequate amount of entropy is not
> useful because a user won't be able to remember it correctly.

Speaking purely for myself, my passphrase is 16 bytes from /dev/urandom
dropped into base64.  It took me a weekend to memorize it, but the peace
of mind has been well worth it.

It is possible, though, that I'm demented.  :)