Secure PDFs with password and remove password security on Mac OS
Multiple security levels
A-PDF Password Security for Mac supports multiple types of security level; you can protect your PDF documents with:
40-bit REC - supported by Adobe Acrobat 3.0 or above
128-bit RC4 - supported by Adobe Acrobat 5.0 or above
128-bit AES - supported by Adobe Acrobat 7.0 or above
256-bit AES - supported by Adobe Acrobat 9.0 or above
See more: http://www.a-pdf.com/security-mac/password_mac.htm