you can try using scrub command at the end of your which can encrypt your usernames, ip addresses, domain names, etc.
....your search | scrub
This needs to be followed for each search you type in the search bar.
If you need information to be encrypted or masked permanently you might need to take a look in to masking/Anonymizing data data in splunk
link:http://docs.splunk.com/Documentation/Splunk/6.0.3/Data/Anonymizedatausingconfigurationfiles
