Have both googled and the descriptions are very similar.
Why are there both files or what do you differ? Are you in competition to each other?Claudia
"/ etc / Security / Opasswd" apparently only under Solaris and is a backup of "/etc/passwd".
"/ etc / shadow "is a file that is used to save" sensitive information "(especially the hashes of passwords) separated from" / etc / passwd ".
That has the advantage that you only Privileged system processes can give access to the hashes in "/ etc / shadow", while even unprivileged processes often need access to user names and group affairs stored in "/ etc / passwd".