At the time of this writing, both 256-bit AES
and 128-bit AES
encryption are considered secure. 256-bit AES
is stronger and should be preferred. However, 256-bit AES
requires PDF version 1.7 whereas 128-bit AES
requires just 1.6. Learn more about PDF encryption here.
Passwords should be 7 characters or more using a combination of numbers, characters and symbols.
Create a password-protected PDF