Use the server's public key to verify it:
https://winscp.net/eng/docs/ssh_verifying_the_host_key

Still, you need means to authenticate, a password or a private key (of your account).

Martin, I believe you are correct that they sent me a server's public key. I have read a ton, but I can't figure out what to do with the public key. I have been working on this off and on for a long time and I am very frustrated.

jrynd wrote:

they must be confusing public and private keys. The public key is on the server, the private key is something you have. Either they sent you the wrong key, or they sent you a private key but told you it was a public key.

Not necessarily. There are four keys, or two key pairs. Your account's key pair. And server's key pair. So it can be a public key, but that of the server, not that of the account.

unclecake wrote:

Now the vender is using a different company to receive the FTP files so I have to update all of the information. I can do most of it, but I can't figure out what to do about the public key. Like I said, I thought that last time I generated a public/private key and sent them the public key. This time they sent me the public key and I can't find any documentation on what I am supposed to do with it. I see the Private key file location in the SSH >> Authentication, but I am lost.

they must be confusing public and private keys. The public key is on the server, the private key is something you have. Either they sent you the wrong key, or they sent you a private key but told you it was a public key.

Maybe they sent you a server's public key, so that you can verify it on the first connect?
https://winscp.net/eng/docs/ssh_verifying_the_host_key

Let me start out by saying I can work my way through WinSCP as I have done in the past, but I don't fully understand it. Several years ago I started using WinSCP with a vendor of ours where we dropped documents onto their server. I created a public/private key pair and everything was very easy from what I remember.

Now the vender is using a different company to receive the FTP files so I have to update all of the information. I can do most of it, but I can't figure out what to do about the public key. Like I said, I thought that last time I generated a public/private key and sent them the public key. This time they sent me the public key and I can't find any documentation on what I am supposed to do with it. I see the Private key file location in the SSH >> Authentication, but I am lost.

Can anyone direct me to the proper terminology or spot for me to figure this out?

Many thanks!