Tamper scripts are basically used in the evasion of simple filters and Web Application Firewalls (WAFs). They are a collection of in-built scripts which modify the injection vector used by SQLMap. There are cases when WAF detects the injection vectors and blocks the whole process. The following table gives a brief description of various tamper scripts and their usage. The comprehensive table was fabricated by Jake Rogers at http://www.forkbombers.com/ so the entire credit goes to him.
Replaces the apostrophe character with its UTF-8 full width counterpart.
Replaces the apostrophe character with its illegal double unicode counterpart.
Appends the encoded ...