Interesting question: First, I'd have to ask why you're implementing a password encryption program to begin with, instead of letting an operating system or application manage this bit of information. I assume you're asking in the context of writing the application that will manage the encryption code itself.
The general contemporary thinking in this regard is not to put passwords in code, but to use certificates, like Kerberos, or trust relationship information, like Federation SAML assertions, in the code since any hacker with enough time and energy can eventually crack an encrypted password.
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This was first published in March 2010