1/*
2 * Copyright (c) 2006-2011 Christian Plattner. All rights reserved.
3 * Please refer to the LICENSE.txt for licensing details.
4 */
5package ch.ethz.ssh2;
6
7/**
8 * An <code>InteractiveCallback</code> is used to respond to challenges sent
9 * by the server if authentication mode "keyboard-interactive" is selected.
10 *
11 * @see Connection#authenticateWithKeyboardInteractive(String,
12 *      String[], InteractiveCallback)
13 *
14 * @author Christian Plattner
15 * @version 2.50, 03/15/10
16 */
17
18public interface InteractiveCallback
19{
20	/**
21	 * This callback interface is used during a "keyboard-interactive"
22	 * authentication. Every time the server sends a set of challenges (however,
23	 * most often just one challenge at a time), this callback function will be
24	 * called to give your application a chance to talk to the user and to
25	 * determine the response(s).
26	 * <p>
27	 * Some copy-paste information from the standard: a command line interface
28	 * (CLI) client SHOULD print the name and instruction (if non-empty), adding
29	 * newlines. Then for each prompt in turn, the client SHOULD display the
30	 * prompt and read the user input. The name and instruction fields MAY be
31	 * empty strings, the client MUST be prepared to handle this correctly. The
32	 * prompt field(s) MUST NOT be empty strings.
33	 * <p>
34	 * Please refer to draft-ietf-secsh-auth-kbdinteract-XX.txt for the details.
35	 * <p>
36	 * Note: clients SHOULD use control character filtering as discussed in
37	 * RFC4251 to avoid attacks by including
38	 * terminal control characters in the fields to be displayed.
39	 *
40	 * @param name
41	 *            the name String sent by the server.
42	 * @param instruction
43	 *            the instruction String sent by the server.
44	 * @param numPrompts
45	 *            number of prompts - may be zero (in this case, you should just
46	 *            return a String array of length zero).
47	 * @param prompt
48	 *            an array (length <code>numPrompts</code>) of Strings
49	 * @param echo
50	 *            an array (length <code>numPrompts</code>) of booleans. For
51	 *            each prompt, the corresponding echo field indicates whether or
52	 *            not the user input should be echoed as characters are typed.
53	 * @return an array of reponses - the array size must match the parameter
54	 *         <code>numPrompts</code>.
55	 */
56	public String[] replyToChallenge(String name, String instruction, int numPrompts, String[] prompt, boolean[] echo)
57			throws Exception;
58}
59