oscore.h

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/* -*- Mode: C; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 
/*
 * Copyright (c) 2018, SICS, RISE AB
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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 */

 
#ifndef _OSCORE_H
#define _OSCORE_H
 
#include "oscore_cose.h"
#include "oscore_context.h"
 
#ifdef __cplusplus
extern "C" {
#endif

 
/* Estimate your header size, especially when using Proxy-Uri. */
#define COAP_MAX_HEADER_SIZE 70
 
/* OSCORE error messages  (to be moved elsewhere  */
#define OSCORE_DECRYPTION_ERROR    100
#define PACKET_SERIALIZATION_ERROR 102
 
/* oscore_cs_params
 * returns cbor array [[param_type], [paramtype, param]]
 */
uint8_t *oscore_cs_params(int8_t param, int8_t param_type, size_t *len);
 
/* oscore_cs_key_params
 * returns cbor array [paramtype, param]
 */
uint8_t *oscore_cs_key_params(cose_curve_t param, int8_t param_type, size_t *len);

ssize_t oscore_encode_option_value(uint8_t *option_buffer,
                                   size_t option_buf_len,
                                   cose_encrypt0_t *cose,
                                   uint8_t group_flag,
                                   uint8_t appendix_b_2);
 
/*
 * Decodes the OSCORE option value and places decoded values into the provided
 * cose structure */
int oscore_decode_option_value(const uint8_t *option_value,
                               size_t option_len,
                               cose_encrypt0_t *cose);
 
/* Creates AAD, creates External AAD and serializes it into the complete AAD
 * structure. Returns serialized size. */
size_t oscore_prepare_aad(const uint8_t *external_aad_buffer,
                          size_t external_aad_len,
                          uint8_t *aad_buffer,
                          size_t aad_size);
 
size_t oscore_prepare_e_aad(oscore_ctx_t *ctx,
                            cose_encrypt0_t *cose,
                            const uint8_t *oscore_option,
                            size_t oscore_option_len,
                            coap_bin_const_t *sender_public_key,
                            uint8_t *external_aad_ptr,
                            size_t external_aad_size);
 
/* Creates Nonce */
void oscore_generate_nonce(cose_encrypt0_t *ptr,
                           oscore_ctx_t *ctx,
                           uint8_t *buffer,
                           uint8_t size);
 
/*Return 1 if OK, Error code otherwise */
uint8_t oscore_validate_sender_seq(oscore_recipient_ctx_t *ctx,
                                   cose_encrypt0_t *cose);
 
/* Return 0 if SEQ MAX, return 1 if OK */
uint8_t oscore_increment_sender_seq(oscore_ctx_t *ctx);
 
/* Restore the sequence number and replay-window to the previous state. This is
 * to be used when decryption fail. */
void oscore_roll_back_seq(oscore_recipient_ctx_t *ctx);

 
#ifdef __cplusplus
}
#endif
 
#endif /* _OSCORE_H */