f53c4db874
The encryption functions should document the expect byte order of inputs and the byte order of the outputs. The sef and sdf functions were also using an older, and incorrect, description of the input, as it only takes the LTK as per CSIP 1.0.0 Signed-off-by: Emil Gydesen <emil.gydesen@nordicsemi.no>
81 lines
2.9 KiB
C
81 lines
2.9 KiB
C
/*
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* Copyright (c) 2019 Bose Corporation
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* Copyright (c) 2021-2022 Nordic Semiconductor ASA
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <stdint.h>
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#include <zephyr/bluetooth/audio/csip.h>
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#include <zephyr/types.h>
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#define BT_CSIP_CRYPTO_KEY_SIZE 16
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#define BT_CSIP_CRYPTO_SALT_SIZE 16
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#define BT_CSIP_CRYPTO_PRAND_SIZE 3
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#define BT_CSIP_CRYPTO_HASH_SIZE 3
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/**
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* @brief Private Set Unique identifier hash function sih.
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*
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* The RSI hash function sih is used to generate a hash value that is
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* used in RSIs - Used by the Coordinated Set Identification service and
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* profile.
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*
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* @param sirk 16-byte SIRK in little-endian byte order.
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* @param r 3-byte random value in little-endian byte order.
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* @param out 3-byte output buffer in little-endian byte order.
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*
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* @return int 0 on success, any other value indicates a failure.
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*/
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int bt_csip_sih(const uint8_t sirk[BT_CSIP_SIRK_SIZE], uint8_t r[BT_CSIP_CRYPTO_PRAND_SIZE],
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uint8_t out[BT_CSIP_CRYPTO_HASH_SIZE]);
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/**
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* @brief SIRK encryption function sef
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*
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* The SIRK encryption function sef is used by the server to encrypt the SIRK
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* with a key K. The value of K depends on the transport on which the pairing
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* between the client and the server was performed.
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*
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* If the pairing was performed on Basic Rate/Enhanced Data Rate (BR/EDR), K is equal to the
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* Link Key shared by the server and the client.
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* K = Link Key.
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*
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* If the pairing was performed on Bluetooth Low Energy (LE), K is equal to the LTK shared by the
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* server and client. That is,
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* K = LTK
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*
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* @param k 16-byte key in little-endian byte order.
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* @param sirk 16-byte unencrypted SIRK key in little-endian byte order.
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* @param out_sirk 16-byte encrypted SIRK key in little-endian byte order.
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*
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* @return int 0 on success, any other value indicates a failure.
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*/
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int bt_csip_sef(const uint8_t k[BT_CSIP_CRYPTO_KEY_SIZE], const uint8_t sirk[BT_CSIP_SIRK_SIZE],
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uint8_t out_sirk[BT_CSIP_SIRK_SIZE]);
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/**
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* @brief SIRK decryption function sdf
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*
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* The SIRK decryption function sdf is used by the client to decrypt the SIRK
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* with a key K. The value of K depends on the transport on which the pairing
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* between the client and the server was performed.
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*
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* If the pairing was performed on Basic Rate/Enhanced Data Rate (BR/EDR), K is equal to the
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* Link Key shared by the server and the client.
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* K = Link Key.
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*
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* If the pairing was performed on Bluetooth Low Energy (LE), K is equal to the LTK shared by the
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* server and client. That is,
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* K = LTK
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*
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* @param k 16-byte key in little-endian byte order.
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* @param sirk 16-byte encrypted SIRK in little-endian byte order.
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* @param out_sirk 16-byte decrypted SIRK in little-endian byte order.
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*
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* @return int 0 on success, any other value indicates a failure.
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*/
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int bt_csip_sdf(const uint8_t k[BT_CSIP_CRYPTO_KEY_SIZE], const uint8_t enc_sirk[BT_CSIP_SIRK_SIZE],
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uint8_t out_sirk[BT_CSIP_SIRK_SIZE]);
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