1)   Encrypt PDF (Secure PDF) 2.3
Encrypt PDF software allows you to encrypt (using standard 40-bit or 128-bit supported by Acrobat Reader 5.0 and up) existing PDFs.
pdf file, pdf secure, Secure PDF, Sensitive PDF, Retrieve PDF, pdf protector, encrypt pdf, encrypted, pdf permission, Encrypt your PDF,

 2)   PDF Security ActiveX 2.0.2008.618
Encrypt and decrypt PDF files Supports PDF user password and owner password protection Password protect opening of the PDF document Disable printing of the PDF document Disable copying of text/graphics
Encrypt PDF, decrypt PDF, PDF encryption, secure PDF, protect PDF,

 3)   Multimedia Protector 2.1
Protect Flash, PDF, Powerpoint, Video, Images and other file types like Word or EXE. Content Protection / Time limited versions / Software Copy Protection / Network licence PC, User, Floating / Shop Integration
Protect Flash, Protect CD, Protect PDF, Protect Video, Protect PPT, protect SWF, encrypt flash, copy protection, powerpoint protection, protect word,

 4)   Encrypt PDF Command Line 2.3
Encrypt PDF software allows you to encrypt (using standard 40-bit or 128-bit supported by Acrobat Reader 5.0 and up) existing PDFs.
pdf file, pdf secure, Secure PDF, Sensitive PDF, Retrieve PDF, pdf protector, encrypt pdf, encrypted, pdf permission, Encrypt your PDF,