Why does checking a wrong password takes longer than checking the right one on Linux?

Posted by Flávio Amieiro on Stack Overflow See other posts from Stack Overflow or by Flávio Amieiro
Published on 2009-04-03T02:24:21Z Indexed on 2010/06/01 22:23 UTC
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linux

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security

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password

This question has always troubled me.

On Linux, when asked for a password, if your input is the correct one, it checks right away, with almost no delay. But, on the other hand, if you type the wrong password, it takes longer to check. Why is that?

I observed this in all Linux distributions I've ever tried.

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