Every day I ssh in to 3 or 4 independent Unix accounts. I have been regarding th

Question

Every day I ssh in to 3 or 4 independent Unix accounts. I have been regarding them as more or less "equivalently secure" on the grounds that I'm using ssh, but after learning of how much variety there is out there in password-hashing schemes and their resistance against dictionary attacks I've become a lot more interested in learning the specific details for the systems I use.

I have found some too-brief summaries of what some OSs use by default (e.g., see here), but I'd like something more detailed. More importantly, I'm less interested in what various OSs do "out-of-the-box" than in what the specific systems I log in to do. Is there a standard way to find this information?

(I hope this question is not too naive. Yes, of course, a password cracker would also like to know the information I'm asking about, but my understanding is that no competently designed password-handling scheme hinges on its being secret. Therefore, I expect that the information I'm after should be readily available to the users of a system.)

Explanation / Answer

If you have root access, use it to cat /etc/shadow (on most Unix flavours) and take a look at it. The second field in the file is the hashed password for each user, and it is generally separated by $ signs into three parts, which are the hashing algorithm, the salt and the hash itself (if it doesn't have the first section then it's using the default hash algorithm, which is DES). $0$ is DES, $1$ is MD5, $2$ and $2a$ are Blowfish, $3$ is NT Hash, $5$ is SHA-256 and $6$ is SHA-512.

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