Uploading SSH Keys

I'm trying to set up a connection between Eloqua and an external server using SSH Key authentication and have generated a pair key in Eloqua and shared that public key so it's configured on the server but having trouble uploading the server's public key into Eloqua. It's requiring both a public and private key when uploading but I'm not sure which private key to upload and keep getting an invalid key error message. Has anyone had success in setting up this kind of connection?? Much appreciated in advance!