VB.NET

SSH HSM Public Key Authentication

Demonstrates SSH public-key authentication using a private key stored on an HSM — a USB token or smart card — accessed through PKCS#11. A session is opened with the vendor's driver, the key handles are located, and an SshKey object is bound to them with UsePkcs11.

Background: The point of an HSM is that the private key is generated on the device and cannot be exported: the signing operation happens on the hardware, so the key material never reaches your application's memory or disk. Even a fully compromised host cannot yield a copy of the key. PKCS#11 is the vendor-neutral interface to such devices, which is why the driver path and the object-finding template are the only vendor-specific parts of this example.

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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 SSH public-key authentication using a private key stored on an HSM (a USB token
'  or smart card) accessed through PKCS#11.
'  
'  Note: Chilkat's PKCS#11 implementation runs on Windows, Linux, macOS, and other supported
'  operating systems.

Dim pkcs11 As New Chilkat.Pkcs11

'  The PKCS#11 driver supplied by your HSM vendor: a .dll on Windows, a .so on Linux, or a
'  .dylib on macOS.
pkcs11.SharedLibPath = "C:/Program Files (x86)/Gemalto/IDGo 800 PKCS#11/IDPrimePKCS1164.dll"

'  The PIN should come from a secure source rather than being hard-coded.
Dim pin As String = "0000"

'  Normal user = 1
Dim userType As Integer = 1

success = pkcs11.QuickSession(userType,pin)
If (success = False) Then
    Debug.WriteLine(pkcs11.LastErrorText)
    Exit Sub
End If


'  Describe the private key object to be located on the HSM.
Dim json As New Chilkat.JsonObject
json.UpdateString("class","private_key")
json.UpdateString("label","MySshKey")

Dim priv_handle As UInt32 = pkcs11.FindObject(json)
If (priv_handle = 0) Then
    Debug.WriteLine(pkcs11.LastErrorText)
    Exit Sub
End If


'  Find the corresponding public key by changing the class in the same template.
json.UpdateString("class","public_key")

Dim pub_handle As UInt32 = pkcs11.FindObject(json)
If (pub_handle = 0) Then
    Debug.WriteLine(pkcs11.LastErrorText)
    Exit Sub
End If


'  Create an SSH key object that uses the HSM handles.  The key type may be "rsa" or "ec".
Dim key As New Chilkat.SshKey
Dim keyType As String = "rsa"
success = key.UsePkcs11(pkcs11,priv_handle,pub_handle,keyType)
If (success = False) Then
    Debug.WriteLine(key.LastErrorText)
    Exit Sub
End If


Dim ssh As New Chilkat.Ssh

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


'  The corresponding public key must already be installed on the SSH server for the account.
'  The signing operation happens on the HSM -- the private key never leaves the device.
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()

pkcs11.Logout()
pkcs11.CloseSession()