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/*
* Copyright (C) 2010 Tobias Brunner
* Copyright (C) 2005-2007 Martin Willi
* Copyright (C) 2005 Jan Hutter
* Hochschule fuer Technik Rapperswil
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*/
/**
* @defgroup diffie_hellman diffie_hellman
* @{ @ingroup crypto
*/
#ifndef DIFFIE_HELLMAN_H_
#define DIFFIE_HELLMAN_H_
typedef enum diffie_hellman_group_t diffie_hellman_group_t;
typedef struct diffie_hellman_t diffie_hellman_t;
typedef struct diffie_hellman_params_t diffie_hellman_params_t;
#include <library.h>
/**
* Diffie-Hellman group.
*
* The modulus (or group) to use for a Diffie-Hellman calculation.
* See IKEv2 RFC 3.3.2 and RFC 3526.
*
* ECP groups are defined in RFC 4753 and RFC 5114.
* ECC Brainpool groups are defined in RFC 6954.
*/
enum diffie_hellman_group_t {
MODP_NONE = 0,
MODP_768_BIT = 1,
MODP_1024_BIT = 2,
MODP_1536_BIT = 5,
MODP_2048_BIT = 14,
MODP_3072_BIT = 15,
MODP_4096_BIT = 16,
MODP_6144_BIT = 17,
MODP_8192_BIT = 18,
ECP_256_BIT = 19,
ECP_384_BIT = 20,
ECP_521_BIT = 21,
MODP_1024_160 = 22,
MODP_2048_224 = 23,
MODP_2048_256 = 24,
ECP_192_BIT = 25,
ECP_224_BIT = 26,
ECP_224_BP = 27,
ECP_256_BP = 28,
ECP_384_BP = 29,
ECP_512_BP = 30,
/** insecure NULL diffie hellman group for testing, in PRIVATE USE */
MODP_NULL = 1024,
/** MODP group with custom generator/prime */
/** Parameters defined by IEEE 1363.1, in PRIVATE USE */
NTRU_112_BIT = 1030,
NTRU_128_BIT = 1031,
NTRU_192_BIT = 1032,
NTRU_256_BIT = 1033,
/** internally used DH group with additional parameters g and p, outside
* of PRIVATE USE (i.e. IKEv2 DH group range) so it can't be negotiated */
MODP_CUSTOM = 65536,
};
/**
* enum name for diffie_hellman_group_t.
*/
extern enum_name_t *diffie_hellman_group_names;
/**
* Implementation of the Diffie-Hellman algorithm, as in RFC2631.
*/
struct diffie_hellman_t {
/**
* Returns the shared secret of this diffie hellman exchange.
*
* Space for returned secret is allocated and must be freed by the caller.
*
* @param secret shared secret will be written into this chunk
* @return TRUE if shared secret computed successfully
*/
bool (*get_shared_secret)(diffie_hellman_t *this, chunk_t *secret)
__attribute__((warn_unused_result));
/**
* Sets the public value of partner.
*
* Chunk gets cloned and can be destroyed afterwards.
*
* @param value public value of partner
* @return TRUE if other public value verified and set
*/
bool (*set_other_public_value)(diffie_hellman_t *this, chunk_t value)
__attribute__((warn_unused_result));
/**
* Gets the own public value to transmit.
*
* Space for returned chunk is allocated and must be freed by the caller.
*
* @param value public value of caller is stored at this location
* @return TRUE if public value retrieved
*/
bool (*get_my_public_value) (diffie_hellman_t *this, chunk_t *value)
__attribute__((warn_unused_result));
/**
* Set an explicit own private value to use.
*
* Calling this method is usually not required, as the DH backend generates
* an appropriate private value itself. It is optional to implement, and
* used mostly for testing purposes.
*
* @param value private value to set
*/
bool (*set_private_value)(diffie_hellman_t *this, chunk_t value)
__attribute__((warn_unused_result));
/**
* Get the DH group used.
*
* @return DH group set in construction
*/
diffie_hellman_group_t (*get_dh_group) (diffie_hellman_t *this);
/**
* Destroys a diffie_hellman_t object.
*/
void (*destroy) (diffie_hellman_t *this);
};
/**
* Parameters for a specific diffie hellman group.
*/
struct diffie_hellman_params_t {
/**
* The prime of the group
*/
const chunk_t prime;
/**
* Generator of the group
*/
const chunk_t generator;
/**
* Exponent length to use
*/
size_t exp_len;
/**
* Prime order subgroup; for MODP Groups 22-24
*/
const chunk_t subgroup;
};
/**
* Initialize diffie hellman parameters during startup.
*/
void diffie_hellman_init();
/**
* Get the parameters associated with the specified diffie hellman group.
*
* Before calling this method, use diffie_hellman_init() to initialize the
* DH group table. This is usually done by library_init().
*
* @param group DH group
* @return The parameters or NULL, if the group is not supported
*/
diffie_hellman_params_t *diffie_hellman_get_params(diffie_hellman_group_t group);
/**
* Check if a given DH group is an ECDH group
*
* @param group group to check
* @return TRUE if group is an ECP group
*/
bool diffie_hellman_group_is_ec(diffie_hellman_group_t group);
/**
* Check if a diffie hellman public value is valid for given group.
*
* @param group group the value is used in
* @param value public DH value to check
* @return TRUE if value looks valid for group
*/
bool diffie_hellman_verify_value(diffie_hellman_group_t group, chunk_t value);
#endif /** DIFFIE_HELLMAN_H_ @}*/
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