text: /* Copyright (c) 2001 Matej Pfajfar.
   * Copyright (c) 2001-2004, Roger Dingledine.
   * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
   * Copyright (c) 2007-2013, The Tor Project, Inc. */
  /* See LICENSE for licensing information */
  
  /**
   * \file onion_tap.h
   * \brief Header file for onion_tap.c.
   **/
  
  #ifndef TOR_ONION_TAP_H
  #define TOR_ONION_TAP_H
  
  #define TAP_ONIONSKIN_CHALLENGE_LEN (PKCS1_OAEP_PADDING_OVERHEAD+\
                                   CIPHER_KEY_LEN+\
                                   DH_KEY_LEN)
  #define TAP_ONIONSKIN_REPLY_LEN (DH_KEY_LEN+DIGEST_LEN)
  
  int onion_skin_TAP_create(crypto_pk_t *router_key,
                        crypto_dh_t **handshake_state_out,
                        char *onion_skin_out);
  
  int onion_skin_TAP_server_handshake(const char *onion_skin,
                                  crypto_pk_t *private_key,
                                  crypto_pk_t *prev_private_key,
                                  char *handshake_reply_out,
                                  char *key_out,
                                  size_t key_out_len);
  
  int onion_skin_TAP_client_handshake(crypto_dh_t *handshake_state,
                                  const char *handshake_reply,
                                  char *key_out,
                                  size_t key_out_len);
  
  #endif
  
  