Most modern IRC daemons should compile on Ubuntu. I believe Ubuntu includes Hybrid as a package named
For the channel monitoring, you will probably be best up writing a script for an IRC bot. Wikipedia also has a comparison of bots. I personally prefer and would suggest Eggdrop.
IRC services share some of the functionality with bots but are unlikely to be suited for such a general purpose but this will depend on exactly what actions you want to take.
In regards to security, you shouldn't run ircd as root and the risk of system compromise is low. As far as communication between users via the server, there is no security as data is not encrypted. As IRC was not originally designed with encryption, there are no comprehensive cryptographic solutions.
As an alternative to ircd for encrypted communication, I would suggest taking a look at silc. It is a new protocol, which was implemented using public key encryption.