How do I get WinSCP to connect to an SSH server with a private key that I specify?

Question

How do I get WinSCP to connect to an SSH server with a private key that I specify.

I don't see the option.

• For example, I have a private key I created with SSH in cygwin. (id_rsa)

  $ ls ~/.ssh -l
  
    -rw------- 1 user None 2602 Dec 24 17:26 id_rsa
    -rw-r--r-- 1 user None  570 Dec 24 17:28 id_rsa.pub
    -rw-r--r-- 1 user None 4562 Apr 27 08:03 known_hosts
  
  $ cat .ssh/id_rsa
  
    -----BEGIN OPENSSH PRIVATE KEY-----
    b3Blb...........wcm9ib29rMQECAw==
    -----END OPENSSH PRIVATE KEY-----
  

  And I have already added the Public key (id_rsa.pub), to authorized_keys on the server.

Answer 1

On the WinSCP Login dialog, click the Advanced button, go to SSH > Authentication, and in the Private key file box, browse for your private key file:

See also https://winscp.net/eng/docs/ui_login_authentication

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If you do not have your key in the PuTTY .ppk format, you will need to change the file filter to All private key files; once you select the SSH key, WinSCP will offer to convert the key for you, saving a copy of the key in .ppk format.

Answer 2

(Martin's answer is quicker than this answer)

The easiest way is to ensure you can connect in PuTTY first since it's very similar to WinSCP:

PuTTY requires the key to be a .ppk [Putty Private Key]

• How to convert an RSA key (like OpenSSH uses) to a .ppk with PuTTYgen:
  1. File → Load private key → Change to show all files
  2. Choose id_rsa to load the RSA key → File → Save private key
• In PuTTY:
  1. Connection → SSH → Auth → Private key file for authentication → Choose the .ppk
  2. PuTTY asks you to specify the username, which is the same username as with OpenSSH [SSH used in cygwin when executing ssh user@ip]
  3. Now put PuTTY aside, as it helps to know how to connect with PuTTY
     
     

At the WinSCP login screen, go to New Site

1. File protocol → SCP [file transfer over SSH]
2. Advanced → SSH → Authentication → Load private key → Choose .ppk created above
   
   PuTTYgen is used to convert an RSA key to a .ppk, which is done in the same way I described above