SFTP public/private key authentication - can it work without the key location?

Question

I use the Jscape library to implement a SFTP client. The pieces of information I need is usually the following: 1. Host 2. Port 3. User ID 4. Private key's location 5. Passphrase (optional in some cases)

My question is : is there any way to use private key without specifying the private key's location? For example, the key could be dropped to a certain location and Jscape or some other SFTP API out there would somehow "see" it?

Jscape doesn't seem to support that. I've tried putting a non-passphrase-protected key next to the sftp.jar file (the Jscape library) and that didn't work.

I know specifying the key's location is fairly straightforward and it certainly is one of the use cases I have. But I do have reasons behind asking this silly-sounding question. I appreciate any insight!

Answer 1

OpenSSH's command line client uses $HOME/.ssh/id_rsa as the default location for the private key, and a few other applications seem to follow this (eg git). So if you're implementing code on top of JScape, you could also use that convention.