Query regarding ssh implementation

Hi,
I have searched enough in web before asking this here. If this is not
the right place to ask please ignore this.

I came to know that there are currently 3 ssh implementations viz.
ssh1,
ssh2 and openssh.=20

On a system where ssh is installed how to find what kind of ssh
implementation that was running on it using a shell script..

The reason why I require this ssh configuration files like
authorized_keys will be at different locations (~/.ssh, ~/.ssh2) with
different file name like authorized_keys or authorized_keys2 with
different format (ssh2 implementation stores file names of the public
keys in authorized keys file).

Please let me know how can I do this..

Regards,
Suresh