Generate Unique Hash Key in PL/SQL
I have a document that i want to send to certain customers. What I've decided to do is send the customer a link to the document that will be stored locally on our server. Obviously for security reasons i don't want to simply send the sequential doc ID allowing customers to change the query string to get other information.
What would be the best way in pl/sql to generate a unique hash key to include in the url? The key would have to be both unique and not easily edited by customers to view other documents.
Any help would be much appreciated.
Faoilean.