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SSH Authenticate using a Smart Card Private Key

Demonstrates using a private key stored on an HSM (smart card or token) for SSH public-key authentication. A JSON template locates the private and public key objects by class, key type, and label, and the returned handles are bound to an SshKey object.

Background: PKCS#11 objects are found by attribute rather than by name alone, which is why a template describing the class, key type, and label is used. An important practical detail is that the returned handles are valid only for the lifetime of the PKCS#11 session — they cannot be cached and reused later, so a subsequent session must locate the objects again. Logging out and closing the session when finished releases the device for other applications.

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Local $bSuccess = False

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

;  Demonstrates using a private key stored on an HSM (smart card or token) for SSH public-key
;  authentication.  Public-key authentication means the client uses the private key, while the
;  corresponding public key is installed on the server under the SSH account.
;  
;  Note: Chilkat's PKCS#11 implementation runs on Windows, Linux, macOS, and other supported
;  operating systems.

$oPkcs11 = ObjCreate("Chilkat.Pkcs11")

;  Use the PKCS#11 driver (.dll, .so, or .dylib) for your particular HSM.
$oPkcs11.SharedLibPath = "C:/Program Files (x86)/Gemalto/IDGo 800 PKCS#11/IDPrimePKCS11.dll"

;  The HSM PIN should come from a secure source rather than being hard-coded.
Local $sPin = "0000"

;  Normal user = 1
Local $iUserType = 1

$bSuccess = $oPkcs11.QuickSession($iUserType,$sPin)
If ($bSuccess = False) Then
    ConsoleWrite($oPkcs11.LastErrorText & @CRLF)
    Exit
EndIf

;  Provide a template describing the PKCS#11 object to find: an RSA private key labeled
;  "MySshKey".  For how such a key is originally imported, see
;  PKCS11 Import SSH Key
$oJsonTemplate = ObjCreate("Chilkat.JsonObject")
$oJsonTemplate.UpdateString("class","private_key")
$oJsonTemplate.UpdateString("key_type","rsa")
$oJsonTemplate.UpdateString("label","MySshKey")

Local $iPrivKeyHandle = $oPkcs11.FindObject($oJsonTemplate)
If ($iPrivKeyHandle = 0) Then
    ConsoleWrite($oPkcs11.LastErrorText & @CRLF)
    Exit
EndIf

;  The handle is only valid for the duration of this PKCS#11 session.  To use the key in a
;  later session, find it again.
ConsoleWrite("private key handle: " & $iPrivKeyHandle & @CRLF)

;  Find the corresponding public key by changing the class in the same template.
$oJsonTemplate.UpdateString("class","public_key")

Local $iPubKeyHandle = $oPkcs11.FindObject($oJsonTemplate)
If ($iPubKeyHandle = 0) Then
    ConsoleWrite($oPkcs11.LastErrorText & @CRLF)
    Exit
EndIf

ConsoleWrite("public key handle: " & $iPubKeyHandle & @CRLF)

;  Create an empty SSH key object and tell it to use the PKCS#11 handles, indicating the key type.
$oSshKey = ObjCreate("Chilkat.SshKey")
$bSuccess = $oSshKey.UsePkcs11($oPkcs11,$iPrivKeyHandle,$iPubKeyHandle,"rsa")
If ($bSuccess = False) Then
    ConsoleWrite($oSshKey.LastErrorText & @CRLF)
    Exit
EndIf

$oSsh = ObjCreate("Chilkat.Ssh")

Local $iPort = 22
$bSuccess = $oSsh.Connect("ssh.example.com",$iPort)
If ($bSuccess = False) Then
    ConsoleWrite($oSsh.LastErrorText & @CRLF)
    Exit
EndIf

;  Authentication uses the existing PKCS#11 session.  The signing happens on the smart card --
;  the private key never leaves the device.
$bSuccess = $oSsh.AuthenticatePk("mySshLogin",$oSshKey)
If ($bSuccess = False) Then
    ConsoleWrite($oSsh.LastErrorText & @CRLF)
    Exit
EndIf

ConsoleWrite("Public-key authentication successful." & @CRLF)

;  ... use the authenticated SSH session ...

$oSsh.Disconnect 

$oPkcs11.Logout()
$oPkcs11.CloseSession()