dh_free(3ssl) [netbsd man page]

DH_new(3SSL)							      OpenSSL							      DH_new(3SSL)

NAME

       DH_new, DH_free - allocate and free DH objects

SYNOPSIS

	#include <openssl/dh.h>

	DH* DH_new(void);

	void DH_free(DH *dh);

DESCRIPTION

       DH_new() allocates and initializes a DH structure.

       DH_free() frees the DH structure and its components. The values are erased before the memory is returned to the system.

RETURN VALUES

       If the allocation fails, DH_new() returns NULL and sets an error code that can be obtained by ERR_get_error(3). Otherwise it returns a
       pointer to the newly allocated structure.

       DH_free() returns no value.

SEE ALSO

       dh(3), ERR_get_error(3), DH_generate_parameters(3), DH_generate_key(3)

HISTORY

       DH_new() and DH_free() are available in all versions of SSLeay and OpenSSL.

1.0.1e								    2013-02-11							      DH_new(3SSL)

dh(3)								      OpenSSL								     dh(3)

NAME

       dh - Diffie-Hellman key agreement

SYNOPSIS

	#include <openssl/dh.h>
	#include <openssl/engine.h>

	DH *   DH_new(void);
	void   DH_free(DH *dh);

	int    DH_size(const DH *dh);

	DH *   DH_generate_parameters(int prime_len, int generator,
		       void (*callback)(int, int, void *), void *cb_arg);
	int    DH_check(const DH *dh, int *codes);

	int    DH_generate_key(DH *dh);
	int    DH_compute_key(unsigned char *key, BIGNUM *pub_key, DH *dh);

	void DH_set_default_method(const DH_METHOD *meth);
	const DH_METHOD *DH_get_default_method(void);
	int DH_set_method(DH *dh, const DH_METHOD *meth);
	DH *DH_new_method(ENGINE *engine);
	const DH_METHOD *DH_OpenSSL(void);

	int DH_get_ex_new_index(long argl, char *argp, int (*new_func)(),
		    int (*dup_func)(), void (*free_func)());
	int DH_set_ex_data(DH *d, int idx, char *arg);
	char *DH_get_ex_data(DH *d, int idx);

	DH *   d2i_DHparams(DH **a, unsigned char **pp, long length);
	int    i2d_DHparams(const DH *a, unsigned char **pp);

	int    DHparams_print_fp(FILE *fp, const DH *x);
	int    DHparams_print(BIO *bp, const DH *x);

DESCRIPTION

       These functions implement the Diffie-Hellman key agreement protocol.  The generation of shared DH parameters is described in
       DH_generate_parameters(3); DH_generate_key(3) describes how to perform a key agreement.

       The DH structure consists of several BIGNUM components.

	struct
	       {
	       BIGNUM *p;	       // prime number (shared)
	       BIGNUM *g;	       // generator of Z_p (shared)
	       BIGNUM *priv_key;       // private DH value x
	       BIGNUM *pub_key;        // public DH value g^x
	       // ...
	       };
	DH

       Note that DH keys may use non-standard DH_METHOD implementations, either directly or by the use of ENGINE modules. In some cases (eg. an
       ENGINE providing support for hardware-embedded keys), these BIGNUM values will not be used by the implementation or may be used for
       alternative data storage. For this reason, applications should generally avoid using DH structure elements directly and instead use API
       functions to query or modify keys.

SEE ALSO

       dhparam(1), bn(3), dsa(3), err(3), rand(3), rsa(3), engine(3), DH_set_method(3), DH_new(3), DH_get_ex_new_index(3),
       DH_generate_parameters(3), DH_compute_key(3), d2i_DHparams(3), RSA_print(3)

50								    2013-03-05								     dh(3)