SSH Authenticate using a Smart Card Private Key

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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.

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.SshKey,
  Chilkat.Pkcs11,
  Chilkat.Ssh,
  Chilkat.JsonObject;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  pkcs11: TPkcs11;
  pin: string;
  userType: Integer;
  jsonTemplate: TJsonObject;
  privKeyHandle: LongWord;
  pubKeyHandle: LongWord;
  sshKey: TSshKey;
  ssh: TSsh;
  port: Integer;

begin
  success := 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.

  pkcs11 := TPkcs11.Create;

  //  Use the PKCS#11 driver (.dll, .so, or .dylib) for your particular HSM.
  pkcs11.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.
  pin := '0000';

  //  Normal user = 1
  userType := 1;

  success := pkcs11.QuickSession(userType,pin);
  if (success = False) then
    begin
      WriteLn(pkcs11.LastErrorText);
      Exit;
    end;

  //  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
  jsonTemplate := TJsonObject.Create;
  jsonTemplate.UpdateString('class','private_key');
  jsonTemplate.UpdateString('key_type','rsa');
  jsonTemplate.UpdateString('label','MySshKey');

  privKeyHandle := pkcs11.FindObject(jsonTemplate);
  if (privKeyHandle = 0) then
    begin
      WriteLn(pkcs11.LastErrorText);
      Exit;
    end;

  //  The handle is only valid for the duration of this PKCS#11 session.  To use the key in a
  //  later session, find it again.
  WriteLn('private key handle: ' + privKeyHandle);

  //  Find the corresponding public key by changing the class in the same template.
  jsonTemplate.UpdateString('class','public_key');

  pubKeyHandle := pkcs11.FindObject(jsonTemplate);
  if (pubKeyHandle = 0) then
    begin
      WriteLn(pkcs11.LastErrorText);
      Exit;
    end;

  WriteLn('public key handle: ' + pubKeyHandle);

  //  Create an empty SSH key object and tell it to use the PKCS#11 handles, indicating the key type.
  sshKey := TSshKey.Create;
  success := sshKey.UsePkcs11(pkcs11,privKeyHandle,pubKeyHandle,'rsa');
  if (success = False) then
    begin
      WriteLn(sshKey.LastErrorText);
      Exit;
    end;

  ssh := TSsh.Create;

  port := 22;
  success := ssh.Connect('ssh.example.com',port);
  if (success = False) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;

  //  Authentication uses the existing PKCS#11 session.  The signing happens on the smart card --
  //  the private key never leaves the device.
  success := ssh.AuthenticatePk('mySshLogin',sshKey);
  if (success = False) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;

  WriteLn('Public-key authentication successful.');

  //  ... use the authenticated SSH session ...

  ssh.Disconnect();

  pkcs11.Logout();
  pkcs11.CloseSession();


  pkcs11.Free;
  jsonTemplate.Free;
  sshKey.Free;
  ssh.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.