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