Harish
<<<<<<<-------Yes you need to store the vendor public key for handshake.
I checked other documents and couple of other projects where they used SFTP with certificate authentication and as per them handshake happens between "your" PUBLIC (which is provided to vendor) and PRIVATE key.
if you notice in SFTP Adapter doc it asked to import the public key under the user id (provided by vendor) SSH folder in vendors SFTP server.
*** Can someone who worked on same scenario confirm this *****
Also second link is not working for me and first link uses SSL keys only to import in Keystore. My question was how to convert public SSH key to public SSL key
-Lalit Chaudhary