Create duplicate content checker script (php/mysql)

I am looking for a duplicate content checker script. The script would check my forum and article directory for duplicated content to make sure the forum, and article directory does not have any duplicated content, then it would search the internet for cross reference for any possible duplicated content using titles, sentences, or any other method used for searching for duplicate content. 1: I should be able to set a % scale. so if i run a search, and I am looking for any duplicate content that has a 10% chance for duplication, then I would be notified. 2: Be able to run it manually 3: Be able to run it via cron per time limit, when the script completes a search, then I will be notified via email if any duplicate content is found, urls, locations of duplicate content, and what is suspected of being duplicate content, and any other helpful info that would determine duplicate content. 4: Options not to recheck certain content that has already been flagged as duplicate content. 5: must be password protected so that just anyone can not access the script to run the script manually. 6: Must run fast, and efficient has possible no matter how much duplicate content that it is searching for. I do not need it bogging down the server looking for duplicate content. 7: Script must be 100% reliable. I do not have the time to be chasing false alarms for duplicate content. php/mysql/cron ## Deliverables 1) All deliverables will be considered "work made for hire" under U.S. Copyright law. Employer will receive exclusive and complete copyrights to all work purchased. (No 3rd party components unless all copyright ramifications are explained AND AGREED TO by the employer on the site per the worker's Worker Legal Agreement). ## Platform php mysql cron