package eu.siacs.conversations.crypto.sasl; import java.security.SecureRandom; import eu.siacs.conversations.entities.Account; import eu.siacs.conversations.xml.TagWriter; public abstract class SaslMechanism { final protected TagWriter tagWriter; final protected Account account; final protected SecureRandom rng; protected static enum State { INITIAL, AUTH_TEXT_SENT, RESPONSE_SENT, VALID_SERVER_RESPONSE, } public static class AuthenticationException extends Exception { public AuthenticationException(final String message) { super(message); } public AuthenticationException(final Exception inner) { super(inner); } } public static class InvalidStateException extends AuthenticationException { public InvalidStateException(final String message) { super(message); } public InvalidStateException(final State state) { this("Invalid state: " + state.toString()); } } public SaslMechanism(final TagWriter tagWriter, final Account account, final SecureRandom rng) { this.tagWriter = tagWriter; this.account = account; this.rng = rng; } /** * The priority is used to pin the authentication mechanism. If authentication fails, it MAY be retried with another * mechanism of the same priority, but MUST NOT be tried with a mechanism of lower priority (to prevent downgrade * attacks). * @return An arbitrary int representing the priority */ public abstract int getPriority(); public abstract String getMechanism(); public String getClientFirstMessage() { return ""; } public String getResponse(final String challenge) throws AuthenticationException { return ""; } }