How secure is the password protect / encryption feature?

[Jesus Saves 33]

How secure is the password protect / encryption feature?  I want to use it for Industry to protect People's Personal Information.

A cursory search on google reveals an abundance of tools to break password-protected PDF documents. Some look like legitimate vendors, and some not. Examples of this would be tools from vendors such as VeryPDF.com and Elcomsoft Co. Ltd. They are merely two examples of password removal tools for PDF documents.

[Test Screen Name · Accepted solution]

Two kinds of password.

1. Control password (not needed to open files).  A lot of software just ignores the protection from this. No value for protection.

2. Open password (needed to open files). These are, like all passwords on fixed files, subject to "brute force" and "dictionary" attacks, since (unlike, say, a bank login) there is no way to block from trying a million or a billion passwords. Using Acrobat X compatible encryption and a long unguessable password should be much as secure as any other password protected file. Of course, once the password is revealed to anyone, the file and password can be freely shared.

[Test Screen Name · Accepted solution]

Two kinds of password.

1. Control password (not needed to open files).  A lot of software just ignores the protection from this. No value for protection.

2. Open password (needed to open files). These are, like all passwords on fixed files, subject to "brute force" and "dictionary" attacks, since (unlike, say, a bank login) there is no way to block from trying a million or a billion passwords. Using Acrobat X compatible encryption and a long unguessable password should be much as secure as any other password protected file. Of course, once the password is revealed to anyone, the file and password can be freely shared.

[margueritek · Accepted solution]

You should use one of the AES encryption schemes (Acrobat 7 or later (AES128), or Acrobat X(AES256)). Acrobat 7 passwords can be up to 30 ASCII characters in length. Acrobat X passwords can be much longer, and can be in arbitrary Unicode characters. How paranoid are you?