public int authenticate(AuthenticationProtocolServer authentication,
    SshMsgUserAuthRequest msg) throws IOException 
{
        NativeAuthenticationProvider authImpl = NativeAuthenticationProvider.getInstance();
        if (authImpl == null) {
            log.error(
                "Cannot perfrom authentication witout native authentication provider");
            return AuthenticationProtocolState.FAILED;
        }
        ByteArrayReader bar = new ByteArrayReader(msg.getRequestData());
        boolean changepwd = ((bar.read() == 0) ? false : true);
        String password = bar.readString();
        String newpassword = null;
        if (changepwd) {
            newpassword = bar.readString();
            try {
                if (!authImpl.changePassword(msg.getUsername(), password,
                            newpassword)) {
                    return AuthenticationProtocolState.FAILED;
                }
                if (authImpl.logonUser(msg.getUsername(), newpassword)) {
                    return AuthenticationProtocolState.COMPLETE;
                } else {
                    return AuthenticationProtocolState.FAILED;
                }
            } catch (PasswordChangeException ex1) {
                return AuthenticationProtocolState.FAILED;
            }
        } else {
            try {
                if (authImpl.logonUser(msg.getUsername(), password)) {
                    log.info(msg.getUsername() +
                        " has passed password authentication");
                    return AuthenticationProtocolState.COMPLETE;
                } else {
                    log.info(msg.getUsername() +
                        " has failed password authentication");
                    return AuthenticationProtocolState.FAILED;
                }
            } catch (PasswordChangeException ex) {
                SshMsgUserAuthPwdChangeReq reply = new SshMsgUserAuthPwdChangeReq(msg.getUsername() +
                        " is required to change password", "");
                authentication.sendMessage(reply);
                return AuthenticationProtocolState.READY;
            }
        }
}

 public final String getMethodName() 
{
      
        return "password";
}

 public  void setAuthenticatedTokens(Map tokens) 
{

}