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/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
* All rights reserved.
*
* This package is an SSL implementation written
* by Eric Young (eay@cryptsoft.com).
* The implementation was written so as to conform with Netscapes SSL.
*
* This library is free for commercial and non-commercial use as long as
* the following conditions are aheared to. The following conditions
* apply to all code found in this distribution, be it the RC4, RSA,
* lhash, DES, etc., code; not just the SSL code. The SSL documentation
* included with this distribution is covered by the same copyright terms
* except that the holder is Tim Hudson (tjh@cryptsoft.com).
*
* Copyright remains Eric Young's, and as such any Copyright notices in
* the code are not to be removed.
* If this package is used in a product, Eric Young should be given attribution
* as the author of the parts of the library used.
* This can be in the form of a textual message at program startup or
* in documentation (online or textual) provided with the package.
*
* 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 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* "This product includes cryptographic software written by
* Eric Young (eay@cryptsoft.com)"
* The word 'cryptographic' can be left out if the rouines from the library
* being used are not cryptographic related :-).
* 4. If you include any Windows specific code (or a derivative thereof) from
* the apps directory (application code) you must include an acknowledgement:
* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
*
* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* The licence and distribution terms for any publically available version or
* derivative of this code cannot be changed. i.e. this code cannot simply be
* copied and put under another distribution licence
* [including the GNU Public Licence.] */
#ifndef OPENSSL_HEADER_DH_H
#define OPENSSL_HEADER_DH_H
#include <openssl/base.h>
#include <openssl/engine.h>
#include <openssl/ex_data.h>
#if defined(__cplusplus)
extern "C" {
#endif
/* DH contains functions for performing Diffie-Hellman key agreement in
* multiplicative groups. */
/* Allocation and destruction. */
/* DH_new returns a new, empty DH object or NULL on error. */
DH *DH_new(void);
/* DH_new_method acts the same as |DH_new| but takes an explicit |ENGINE|. */
DH *DH_new_method(const ENGINE *engine);
/* DH_free decrements the reference count of |dh| and frees it if the reference
* count drops to zero. */
void DH_free(DH *dh);
/* DH_up_ref increments the reference count of |dh|. */
int DH_up_ref(DH *dh);
/* Standard parameters.
*
* These functions return new DH objects with standard parameters configured
* that use the given ENGINE, which may be NULL. They return NULL on allocation
* failure. */
/* These parameters are taken from RFC 5114. */
DH *DH_get_1024_160(const ENGINE *engine);
DH *DH_get_2048_224(const ENGINE *engine);
DH *DH_get_2048_256(const ENGINE *engine);
/* Parameter generation. */
#define DH_GENERATOR_2 2
#define DH_GENERATOR_5 5
/* DH_generate_parameters_ex generates a suitable Diffie-Hellman group with a
* prime that is |prime_bits| long and stores it in |dh|. The generator of the
* group will be |generator|, which should be |DH_GENERATOR_2| unless there's a
* good reason to use a different value. The |cb| argument contains a callback
* function that will be called during the generation. See the documentation in
* |bn.h| about this. In addition to the callback invocations from |BN|, |cb|
* will also be called with |event| equal to three when the generation is
* complete. */
int DH_generate_parameters_ex(DH *dh, int prime_bits, int generator,
BN_GENCB *cb);
/* Diffie-Hellman operations. */
/* DH_generate_key generates a new, random, private key and stores it in
* |dh|. It returns one on success and zero on error. */
int DH_generate_key(DH *dh);
/* DH_compute_key calculates the shared key between |dh| and |peers_key| and
* writes it as a big-endian integer into |out|, which must have |DH_size|
* bytes of space. It returns the number of bytes written, or a negative number
* on error. */
ssize_t DH_compute_key(uint8_t *out, const BIGNUM *peers_key, DH *dh);
/* Utility functions. */
/* DH_size returns the number of bytes in the DH group's prime. */
int DH_size(const DH *dh);
#define DH_CHECK_P_NOT_PRIME 0x01
#define DH_CHECK_P_NOT_SAFE_PRIME 0x02
#define DH_CHECK_UNABLE_TO_CHECK_GENERATOR 0x04
#define DH_CHECK_NOT_SUITABLE_GENERATOR 0x08
#define DH_CHECK_Q_NOT_PRIME 0x10
#define DH_CHECK_INVALID_Q_VALUE 0x20
#define DH_CHECK_INVALID_J_VALUE 0x40
/* DH_check checks the suitability of |dh| as a Diffie-Hellman group. and sets
* |DH_CHECK_*| flags in |*out_flags| if it finds any errors. It returns one if
* |*out_flags| was successfully set and zero on error.
*
* Note: these checks may be quite computationally expensive. */
int DH_check(const DH *dh, int *out_flags);
#define DH_CHECK_PUBKEY_TOO_SMALL 1
#define DH_CHECK_PUBKEY_TOO_LARGE 2
/* DH_check_pub_key checks the suitability of |pub_key| as a public key for the
* DH group in |dh| and sets |DH_CHECK_PUBKEY_*| flags in |*out_flags| if it
* finds any errors. It returns one if |*out_flags| was successfully set and
* zero on error. */
int DH_check_pub_key(const DH *dh, const BIGNUM *pub_key, int *out_flags);
/* DHparams_dup allocates a fresh |DH| and copies the parameters from |dh| into
* it. It returns the new |DH| or NULL on error. */
DH *DHparams_dup(const DH *dh);
/* ASN.1 functions. */
/* d2i_DHparams parses an ASN.1, DER encoded Diffie-Hellman parameters
* structure from |len| bytes at |*inp|. If |ret| is not NULL then, on exit, a
* pointer to the result is in |*ret|. If |*ret| is already non-NULL on entry
* then the result is written directly into |*ret|, otherwise a fresh |DH| is
* allocated. On successful exit, |*inp| is advanced past the DER structure. It
* returns the result or NULL on error. */
DH *d2i_DHparams(DH **ret, const unsigned char **inp, long len);
/* i2d_DHparams marshals |in| to an ASN.1, DER structure. If |outp| is not NULL
* then the result is written to |*outp| and |*outp| is advanced just past the
* output. It returns the number of bytes in the result, whether written or
* not, or a negative value on error. */
int i2d_DHparams(const DH *in, unsigned char **outp);
/* ex_data functions.
*
* These functions are wrappers. See |ex_data.h| for details. */
int DH_get_ex_new_index(long argl, void *argp, CRYPTO_EX_new *new_func,
CRYPTO_EX_dup *dup_func, CRYPTO_EX_free *free_func);
int DH_set_ex_data(DH *d, int idx, void *arg);
void *DH_get_ex_data(DH *d, int idx);
/* dh_method contains function pointers to override the implementation of DH.
* See |engine.h| for details. */
struct dh_method {
struct openssl_method_common_st common;
/* app_data is an opaque pointer for the method to use. */
void *app_data;
/* init is called just before the return of |DH_new_method|. It returns one
* on success or zero on error. */
int (*init)(DH *dh);
/* finish is called before |dh| is destructed. */
void (*finish)(DH *dh);
/* generate_parameters is called by |DH_generate_parameters_ex|. */
int (*generate_parameters)(DH *dh, int prime_bits, int generator,
BN_GENCB *cb);
/* generate_parameters is called by |DH_generate_key|. */
int (*generate_key)(DH *dh);
/* generate_parameters is called by |DH_compute_key|. */
ssize_t (*compute_key)(DH *dh, uint8_t *out, const BIGNUM *pub_key);
};
struct dh_st {
DH_METHOD *meth;
BIGNUM *p;
BIGNUM *g;
BIGNUM *pub_key; /* g^x */
BIGNUM *priv_key; /* x */
/* priv_length contains the length, in bits, of the private value. If zero,
* the private value will be the same length as |p|. */
unsigned priv_length;
BN_MONT_CTX *method_mont_p;
/* Place holders if we want to do X9.42 DH */
BIGNUM *q;
BIGNUM *j;
unsigned char *seed;
int seedlen;
BIGNUM *counter;
int flags;
int references;
CRYPTO_EX_DATA ex_data;
};
#if defined(__cplusplus)
} /* extern C */
#endif
#define DH_F_generate_parameters 100
#define DH_F_generate_key 101
#define DH_F_compute_key 102
#define DH_F_DH_new_method 103
#define DH_R_INVALID_PUBKEY 100
#define DH_R_BAD_GENERATOR 101
#define DH_R_MODULUS_TOO_LARGE 102
#define DH_R_NO_PRIVATE_VALUE 103
#endif /* OPENSSL_HEADER_DH_H */