How do I create an 8-OCTET Password?

Question

I am having to share a PC with someone who,in some fields,is a Business colleague but in others he is a Competitor. He also happens to be a Computer Genius and I need to move to a higher level of Password Security on some of my more sensitive files. Can anyone guide me in how I can create an 8-OCTET PASSWORD that will give me piece of mind?

Answer 1

First, note that if your friend has physical access to the machine, it is probably possible for your friend to install either a software or hardware keylogger to simply read your password, or your source code, directly; other possibilities include modifying your encryption software to save a copy of all files being encrypted into another directory.

This may not be a problem that can be solved.

Second, are you already using some encryption software, and want to know how to generate a good password? Or are you looking for software recommendations?

I'd recommend using GnuPG for encrypting your files:

$ gpg -c -o /tmp/secret /etc/motd
gpg: gpg-agent is not available in this session
Enter passphrase:
Repeat passphrase:
$
$ gpg /tmp/secret
gpg: CAST5 encrypted data
gpg: gpg-agent is not available in this session
Enter passphrase:
gpg: encrypted with 1 passphrase
gpg: /tmp/secret: unknown suffix
Enter new filename [motd]:
gpg: WARNING: message was not integrity protected
$

You can type whatever you want for the passphrase, long or short.

Third, the passphrase itself, I recommend stealing the algorithm used in Openwall Linux's pam_tcb tool: pick two or three random words from /usr/share/dict/words, and place punctuations or numbers (or both) between them: Random*Word)Assortment or Ugly%banana7elements or so forth.

On my system, with a 98000-line words file (16.5 bits of entropy per word) and the symbols easily accessible on my keyboard (36 symbols and numbers, 5.1 bits of entropy each), this would let you generate 59 bits of entropy with three words and two symbols -- just keep going until you're happy with the strength. Such passphrases are usually much easier to remember than strictly randomly generated passwords, but they do have to be significantly longer to provide the same strength.

Answer 2

Why eight octets? (I presume you mean octet in the 8-bits/a byte/an ASCII character sense?)

Irrespective, there are a wide variety of password generators that generate a random mix of alpha (mixed case) and numeric characters out there, so I'd recommend using one of these.