Howard Chu wrote:
You might argue that the MIT approach is more correct, but I would
say that it's highly inconsistent, and inconsistency is highly
undesirable in a security mechanism. For instance, by your
thinking, if you decide that security contexts must all be
invalidated whenever and wherever they are changed, then you also
need to close all connections whenever somebody changes their
password, because any sessions established with the old password
must now be considered invalid.
Not at all. My password has no role in protecting that connection
once it has been established.
No, but it allowed you to establish the connection in the first place.
As such, by your logic, changing it should invalidate the connection.
Sorry, but this is rubbish. By your logic, if one joins a conspirative
gathering using a secret password and then is told than in future there
is a new secret passphrase, he would then be required to leave the room
again an reenter it using the new passphrase. There is absolutely no
security value in this, just a small entertainment value perhaps.
Reestablishing expired encryption keys clearly has a security value, due
to brute force issues on current connection keys.
But if somebody has brute-forced your initial shared secret to establish
the connection an you have changed it in the meantime, he will not be
more able to establish a connection if you keep that old connection.
Bye
Tim
