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Today I upgrade my server to ubuntu 10 lucid, The first thing that occur to me is the new encrypted method, it's the default line


since it starts with $6$, I figured out it's sha-512 method, so I tried to use mkpasswd tool

mkpasswd -m sha-512 123456

so I add a new line to the shadow file


but it doesn't work! probably dues to the salt, I don't know what it is, so I didn't specify.

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Why do you not just add the user using adduser and set a password using passwd? – Paul Dec 25 '11 at 11:11
@Paul, just want to say what's going under the hound – mko Dec 25 '11 at 15:24

The salt is in the second field of the password:


So when you create your passwd, pick a salt:

mkpasswd -m sha-512 <password> <salt>

Then you'll get a line

$6$<salt>$<encrypted password>

Then you can add this to your shadow file:

yozloy:$6$<salt>$<encrypted password>:...

Ie, the salt you specify remains the same in the shadow file as when you type it on the command line

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mkpasswd -m sha-512 12345 -S ih6NzSZL

However, be aware that the result might actually be longer the original.

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Is there a quickway to check the password to see if it works? – CMCDragonkai Jan 19 at 6:34

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