Free pdf encryption software to lock pdf files with password security. Set pdf user password, owner password. User password to restrict pdf opening & owner password to restrict pdf edit, print & copy, supports RC4 and AES encryption. Disallow pdf form filling, signing, commenting, page extraction, conversion etc using our pdf encryption software. Pdf lock software is Windows compatible utility, supports encryption of batch pdf documents. You are provided with two types of password, one is user password and another owner password. User password is optional to input and is needed if you are not wishing to open document by unauthorized user otherwise use owner password if you wish to apply access restrictions. Pdf restrictions which can be applied over the documents are optional i.e. you can select any specific set of restriction for your document. Once user password is applied, only authorized person can access document with limited access. User need to open document with owner password, if wishing to access fully with allowed pdf edit, print or copy option. Program supports 40-bit as well as 128-bit encryption level security to lock pdf documents.