B4X

Authenticate an IMAP SSH Tunnel with a Private Key

Demonstrates the Chilkat Imap.SshAuthenticatePk method, which authenticates the SSH tunnel using a username and an SshKey private key. The first argument is the SSH login name and the second is the private key. Call SshOpenTunnel first; the matching public key must already be authorized for the login on the SSH server.

Note: The private-key path is relative to the application's current working directory. Supply the path to your own key file.

Background: Public-key authentication is the usual choice for unattended/automated SSH access: the private key stays on the client and the server is configured to trust the corresponding public key, so no reusable password travels over the wire. The SshKey object can import keys in several formats — this example uses an OpenSSH private key.

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Dim success As Boolean = False

'  Demonstrates the Imap.SshAuthenticatePk method, which authenticates the SSH tunnel using a
'  username and a private key.  The 1st argument is the SSH login name and the 2nd is an SshKey
'  private key.  Call SshOpenTunnel first.

Dim imap As ChilkatImap
imap.Initialize("imap")

Dim sshPort As Int = 22
success = imap.SshOpenTunnel("ssh.example.com", sshPort)
If success = False Then
    Log(imap.LastErrorText)
    Return
End If


'  Load the SSH private key.  LoadText returns the file's text, which is then imported.
Dim privKey As ChilkatSshKey
privKey.Initialize
Dim keyStr As String = privKey.LoadText("qa_data/id_rsa")
If privKey.LastMethodSuccess = False Then
    Log(privKey.LastErrorText)
    Return
End If

success = privKey.FromOpenSshPrivateKey(keyStr)
If success = False Then
    Log(privKey.LastErrorText)
    Return
End If


'  Authenticate the SSH tunnel with the private key.  The matching public key must already be
'  authorized for the login on the SSH server.
success = imap.SshAuthenticatePk("sshUser", privKey)
If success = False Then
    Log(imap.LastErrorText)
    Return
End If


'  With the SSH tunnel in place, connect and log in to the IMAP server as usual.  The IMAP
'  traffic flows through the tunnel automatically.
imap.Ssl = True
imap.Port = 993
success = imap.Connect("imap.example.com")
If success = False Then
    Log(imap.LastErrorText)
    Return
End If

success = imap.Login("user@example.com", "myPassword")
If success = False Then
    Log(imap.LastErrorText)
    Return
End If


success = imap.Disconnect
If success = False Then
    Log(imap.LastErrorText)
    Return
End If


success = imap.SshCloseTunnel
If success = False Then
    Log(imap.LastErrorText)
    Return
End If