89 lines
2.7 KiB
C
89 lines
2.7 KiB
C
/*
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* ECDH params to be used with kpp API
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*
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* Copyright (c) 2016, Intel Corporation
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* Authors: Salvatore Benedetto <salvatore.benedetto@intel.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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*/
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#ifndef _CRYPTO_ECDH_
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#define _CRYPTO_ECDH_
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/**
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* DOC: ECDH Helper Functions
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*
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* To use ECDH with the KPP cipher API, the following data structure and
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* functions should be used.
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*
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* The ECC curves known to the ECDH implementation are specified in this
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* header file.
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*
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* To use ECDH with KPP, the following functions should be used to operate on
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* an ECDH private key. The packet private key that can be set with
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* the KPP API function call of crypto_kpp_set_secret.
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*/
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/* Curves IDs */
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#define ECC_CURVE_NIST_P192 0x0001
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#define ECC_CURVE_NIST_P256 0x0002
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/**
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* struct ecdh - define an ECDH private key
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*
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* @curve_id: ECC curve the key is based on.
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* @key: Private ECDH key
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* @key_size: Size of the private ECDH key
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*/
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struct ecdh {
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unsigned short curve_id;
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char *key;
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unsigned short key_size;
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};
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/**
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* crypto_ecdh_key_len() - Obtain the size of the private ECDH key
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* @params: private ECDH key
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*
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* This function returns the packet ECDH key size. A caller can use that
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* with the provided ECDH private key reference to obtain the required
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* memory size to hold a packet key.
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*
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* Return: size of the key in bytes
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*/
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unsigned int crypto_ecdh_key_len(const struct ecdh *params);
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/**
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* crypto_ecdh_encode_key() - encode the private key
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* @buf: Buffer allocated by the caller to hold the packet ECDH
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* private key. The buffer should be at least crypto_ecdh_key_len
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* bytes in size.
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* @len: Length of the packet private key buffer
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* @p: Buffer with the caller-specified private key
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*
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* The ECDH implementations operate on a packet representation of the private
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* key.
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*
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* Return: -EINVAL if buffer has insufficient size, 0 on success
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*/
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int crypto_ecdh_encode_key(char *buf, unsigned int len, const struct ecdh *p);
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/**
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* crypto_ecdh_decode_key() - decode a private key
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* @buf: Buffer holding a packet key that should be decoded
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* @len: Length of the packet private key buffer
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* @p: Buffer allocated by the caller that is filled with the
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* unpacked ECDH private key.
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*
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* The unpacking obtains the private key by pointing @p to the correct location
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* in @buf. Thus, both pointers refer to the same memory.
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*
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* Return: -EINVAL if buffer has insufficient size, 0 on success
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*/
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int crypto_ecdh_decode_key(const char *buf, unsigned int len, struct ecdh *p);
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#endif
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