VB.NET

SFTP Authenticate with a SecureString Password and Private Key

Demonstrates the Chilkat SFtp.AuthenticateSecPwPk method, which authenticates using SecureString login and password objects together with a private key. The third argument is the SshKey private key.

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

Background: This is the SecureString form of two-factor SFTP authentication: the password is held encrypted in memory and combined with a private key for servers that require both. It is the most protective option when a deployment mandates two-factor SSH and you also want to minimize plaintext credential exposure in the process.

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Dim success As Boolean = False

'  Demonstrates the SFtp.AuthenticateSecPwPk method, which authenticates using SecureString login
'  and password objects together with a private key.  The 1st argument is the username, the 2nd
'  is the password, and the 3rd is an SshKey private key.

Dim sftp As New Chilkat.SFtp

'  Step 1: Connect the SSH transport.  Port 22 is the usual port.
Dim port As Integer = 22
success = sftp.Connect("sftp.example.com",port)
If (success = False) Then
    Debug.WriteLine(sftp.LastErrorText)
    Exit Sub
End If


'  Normally you would not hard-code the password in source.  You should instead obtain it
'  from an interactive prompt, environment variable, or a secrets vault.
Dim password As String = "mySshPassword"

'  Load the SSH private key.  LoadText reads the file's text, which is then imported.
Dim privKey As New Chilkat.SshKey
Dim keyText As String = privKey.LoadText("qa_data/id_rsa")
If (privKey.LastMethodSuccess = False) Then
    Debug.WriteLine(privKey.LastErrorText)
    Exit Sub
End If

success = privKey.FromOpenSshPrivateKey(keyText)
If (success = False) Then
    Debug.WriteLine(privKey.LastErrorText)
    Exit Sub
End If


'  Place the login and password into SecureString objects.
Dim secureLogin As New Chilkat.SecureString
secureLogin.Append("mySshLogin")
Dim securePassword As New Chilkat.SecureString
securePassword.Append(password)

success = sftp.AuthenticateSecPwPk(secureLogin,securePassword,privKey)
If (success = False) Then
    Debug.WriteLine(sftp.LastErrorText)
    Exit Sub
End If


'  Step 3: Open the SFTP subsystem.  This must be done after authentication and before any
'  file or directory operations.
success = sftp.InitializeSftp()
If (success = False) Then
    Debug.WriteLine(sftp.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("Authenticated.")

sftp.Disconnect()