Most of the wordpress templates achieve this by just adding a few lines of base64 encoded script in one of the template files, decoded and eval()'ed on run, though this won't stop everyone from removing it.
You can make it a bit more secure by adding checker scripts like that to multiple files and making them cross-dependent.
deliteblogger Reviewed by deliteblogger on . how to encrypt wordpress and blogger footer ? hi i m about to design wordprees and blogger templetes so if anyone can help me and tell me how i encrypt its footer so if anyone remove my copyrights the website doesnt work and a phrase appear like this All the links in the footer should remain intact. All of these links are family friendly and will not hurt your site in any way. thanks Rating: 5