A client says they can't accept password-protected PDFs to put in their payroll system, so I have to send them without security. I don't want to send unsecured PDFs via e-mail because e-mail is inherently insecure. I figured a good alternative was, instead of password-protecting each PDF, I could encrypt the containing folder with 7ZIP, which I got from https://www.7-zip.org/ You can see the encryption box at the bottom-right:
At first I was optimistic about this option, but a quick Google search led me to articles such as this one where apparently there are easy to find tools, such as 7z Cracker:
"7z Cracker is an opensource cracking tool which can extract any password protected 7zip file".
I also found this answer in this forum that talks about John The Ripper:
"John The Ripper can crack these AES-256 encrypted archives."
Does this mean that 7ZIP encryption is basically useless? Are these password crackers effective at circumventing this security measure? Secondly, are password-protected PDFs also this easy to break into?