[Pki-devel] [PATCH] Session-based nonces.

Previously nonces were stored in a global map which might not scale well due to some issues: 1. The map used the nonces as map keys. There were possible nonce collisions which required special handling. 2. The collision handling code was not thread safe. There were possible race conditions during concurrent modifications. 3. The map was shared and size limited. If there were a lot of users using the system, valid nonces could get pruned. 4. The map mapped the nonces to client certificates. This limited the possible authentication methods that could be supported. Now the code has been modified such that each user has a private map in the user's session to store the nonces. Additional locking has been implemented to protect against concurrent modifications. The map now uses the target of the operation as the map key, eliminating possible collisions and allowing the use of other authentication methods. Since this is a private map, it's not affected by the number of users using the system. Ticket #474 -- Endi S. Dewata