B4X

SSH Tunnel Authenticate with a SecureString Password and Private Key

Demonstrates the Chilkat SshTunnel.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. Absolute paths may also be used. Supply the path to your own key file.

Background: This is the SecureString form of two-factor tunnel 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 a long-running process.

Chilkat B4X Downloads

Download Chilkat for B4X

B4X

Dim success As Boolean = False

'  Demonstrates the SshTunnel.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 tunnel As ChilkatSshTunnel
tunnel.Initialize("tunnel")

'  The tunnel forwards accepted local connections to this destination through the SSH server.
tunnel.DestHostname = "db.internal.example.com"
tunnel.DestPort = 5432

'  Connect to the SSH server.  This performs the TCP/proxy connection and SSH handshake, but
'  does not authenticate yet.
Dim sshPort As Int = 22
success = tunnel.Connect("ssh.example.com", sshPort)
If success = False Then
    Log(tunnel.LastErrorText)
    Return
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 ChilkatSshKey
privKey.Initialize
Dim keyText As String = privKey.LoadText("qa_data/id_rsa")
If privKey.LastMethodSuccess = False Then
    Log(privKey.LastErrorText)
    Return
End If

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


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

success = tunnel.AuthenticateSecPwPk(secureLogin, securePassword, privKey)
If success = False Then
    Log(tunnel.LastErrorText)
    Return
End If

Log("Authenticated.")

'  After authenticating, call BeginAccepting to start listening for local connections to forward.

Dim waitForThreadExit As Boolean = True
success = tunnel.CloseTunnel(waitForThreadExit)
If success = False Then
    Log(tunnel.LastErrorText)
    Return
End If