can we write program to get password of linux user [closed]

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be re开发者_如何转开发opened, visit the help center. Closed 12 years ago.

can we write a program in java to get usernames and passwords

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You can get usernames by reading /etc/passwd file.

You cannot get passwords unless you try to decrypt them, and that's not practical...

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No, we can't.

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Without a brute-force attack and at least a list of the encrypted passwords, you are out of luck.

Also read this http://www.linux.org/docs/ldp/howto/Security-HOWTO/password-security.html

and this http://www.cyberciti.biz/faq/understanding-etcpasswd-file-format/