VB.NET

SSH Public Key Authentication

Demonstrates authenticating with an SSH server using public-key authentication. A private key is loaded into an SshKey object and passed to AuthenticatePk. The matching public key must already be installed on the server for the account.

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 standard for unattended and automated SSH: the private key never leaves the client, the server merely trusts the corresponding public key, and no reusable password crosses the wire. SshKey imports several formats — OpenSSH PEM keys via FromOpenSshPrivateKey and PuTTY .ppk files via FromPuttyPrivateKey — encrypted or not. For an encrypted key, set the Password property before importing. Note that LoadText is only a convenience for reading a text file into a string; it does not itself load the key.

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Dim success As Boolean = False

'  This example requires the Chilkat API to have been previously unlocked.
'  See Global Unlock Sample for sample code.

'  Demonstrates authenticating with an SSH server using public-key authentication.  The matching
'  public key must already be installed on the SSH server for the account.

Dim ssh As New Chilkat.Ssh

'  Timeouts, in milliseconds.
ssh.ConnectTimeoutMs = 5000
ssh.ReadTimeoutMs = 15000

Dim hostname As String = "ssh.example.com"
Dim port As Integer = 22
success = ssh.Connect(hostname,port)
If (success = False) Then
    Debug.WriteLine(ssh.LastErrorText)
    Exit Sub
End If


'  LoadText is a convenience method that reads any text file into a string.  It does not itself
'  load the key.
Dim key As New Chilkat.SshKey
Dim privKeyText As String = key.LoadText("qa_data/my_private_key.pem")
If (key.LastMethodSuccess = False) Then
    Debug.WriteLine(key.LastErrorText)
    Exit Sub
End If


'  Import the private key.  Both OpenSSH and PuTTY formats are supported, encrypted or not.
'  This example loads an unencrypted OpenSSH-format key; for a PuTTY .ppk file, call
'  FromPuttyPrivateKey instead.  For an encrypted key, set key.Password before importing.
success = key.FromOpenSshPrivateKey(privKeyText)
If (success = False) Then
    Debug.WriteLine(key.LastErrorText)
    Exit Sub
End If


success = ssh.AuthenticatePk("mySshLogin",key)
If (success = False) Then
    Debug.WriteLine(ssh.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("Public-key authentication successful.")

ssh.Disconnect()