Entropy

[borgward]

I ran dd if=/dev/random bs=1 count=32 2>/dev/null | base64 -w 0 | rev | cut -b 2- | rev to create secure password.

jdLtcA0QawkgrYWDWkMEhAy9JCPX0hCwU/H0emcTew7QuTowMLax1tzKiqsFWhh


While writing it down I noticed elements that could qualify as dictionary words: awk, ME, JCP, emc, Tow, Lax.

cat /proc/sys/kernel/random/entropy_avail

3968

How much entropy do I need to produce a strong password for critical use? What are the factors that determine the amount of entropy in a system.

[Chayak]

You're reading too much into it. That kind of password even if there are elements that could be words is perfectly secure.
Check https://www.grc.com/haystack.htm

[borgward]

I previously checked out haystack. I also found a lot of disagreement about their conclusions, especially for critically important stuff. I would appreciate an answer that addresses my questions:

How much entropy do I need to produce a strong password for critical use?

What are the factors that determine the amount of entropy in a system.

[bashiergui]

Just because there happen to be a few 3-letter combinations that spell a word does not make it less random. You can often find what you percieve to be patterns in chaos.

Use /dev/urandom instead of /dev/random. Here's a good discussion elaborating on that and your question. http://security.stackexchange.com/qu...m-entropy-pool

[HiImTye]

that password is perfectly secure, you should be looking more at the crypt() function than entropy

[donsy]

You generated a 64-character password comprising upper and lower case letters and numbers for a total of 62 possibilities in each character location. The entropy per character for that is log2(62) = 5.954. The entropy for your generated 64-character password is 5.954*64 = 381.069 bits, which should be more than sufficient over your lifetime.

If you're worried about embedded words check out pwgen to generate your passwords. For example:

pwgen -v 64

will generate 64 character passwords with no vowels.

[tgalati4]

There are a few tools that you can use to increase the default entropy provided by linux systems:

http://manpages.ubuntu.com/manpages/...unter.3pm.html

http://manpages.ubuntu.com/manpages/...n8/rngd.8.html

You could write a script that takes the current entropy and adds entropy to it (presumably increasing entropy by some random amount), then use that for your security purposes.