code: /*
   * Copyright (c) 2019 the Eclipse Milo Authors
   *
   * This program and the accompanying materials are made
   * available under the terms of the Eclipse Public License 2.0
   * which is available at https://www.eclipse.org/legal/epl-2.0/
   *
   * SPDX-License-Identifier: EPL-2.0
   */
  
  package org.eclipse.milo.opcua.sdk.client.api.identity;
  
  import org.eclipse.milo.opcua.stack.core.types.builtin.ByteString;
  import org.eclipse.milo.opcua.stack.core.types.structured.EndpointDescription;
  import org.eclipse.milo.opcua.stack.core.types.structured.SignatureData;
  import org.eclipse.milo.opcua.stack.core.types.structured.UserIdentityToken;
  
  public interface IdentityProvider {
  
      /**
       * Return the {@link UserIdentityToken} and {@link SignatureData} (if applicable for the token) to use when
       * activating a session.
       *
       * @param endpoint the {@link EndpointDescription} being connected to.
       * @return a {@link SignedIdentityToken} containing the {@link UserIdentityToken} and {@link SignatureData}.
       */
      SignedIdentityToken getIdentityToken(EndpointDescription endpoint, ByteString serverNonce) throws Exception;
  
  }
  