#include#include
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);
Initially, the default DH_METHOD is the OpenSSL internal implementation, as returned by _D_H___O_p_e_n_S_S_L_(_).
_D_H___s_e_t___d_e_f_a_u_l_t___m_e_t_h_o_d_(_) makes mmeetthh the default method for all DH structures created later. NNBB: This is true only whilst no ENGINE has been set as a default for DH, so this function is no longer recommended.
_D_H___g_e_t___d_e_f_a_u_l_t___m_e_t_h_o_d_(_) returns a pointer to the current default DH_METHOD. However, the meaningfulness of this result is dependent on whether the ENGINE API is being used, so this function is no longer recommended.
_D_H___s_e_t___m_e_t_h_o_d_(_) selects mmeetthh to perform all operations using the key ddhh. This will replace the DH_METHOD used by the DH key and if the previous method was supplied by an ENGINE, the handle to that ENGINE will be released during the change. It is possible to have DH keys that only work with certain DH_METHOD implementations (eg. from an ENGINE module that supports embedded hardware-protected keys), and in such cases attempting to change the DH_METHOD for the key can have unexpected results.
_D_H___n_e_w___m_e_t_h_o_d_(_) allocates and initializes a DH structure so that eennggiinnee will be used for the DH operations. If eennggiinnee is NULL, the default ENGINE for DH operations is used, and if no default ENGINE is set, the DH_METHOD controlled by _D_H___s_e_t___d_e_f_a_u_l_t___m_e_t_h_o_d_(_) is used.
typedef struct dh_meth_st { /* name of the implementation */ const char *name;
/* generate private and public DH values for key agreement */ int (*generate_key)(DH *dh);
/* compute shared secret */ int (*compute_key)(unsigned char *key, BIGNUM *pub_key, DH *dh);
/* compute r = a ^ p mod m (May be NULL for some implementations) */ int (*bn_mod_exp)(DH *dh, BIGNUM *r, BIGNUM *a, const BIGNUM *p, const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx);
/* called at DH_new */ int (*init)(DH *dh);
/* called at DH_free */ int (*finish)(DH *dh);
int flags;
char *app_data; /* ?? */
} DH_METHOD;
_D_H___s_e_t___d_e_f_a_u_l_t___m_e_t_h_o_d_(_) returns no value.
_D_H___s_e_t___m_e_t_h_o_d_(_) returns non-zero if the provided mmeetthh was successfully set as the method for ddhh (including unloading the ENGINE handle if the previous method was supplied by an ENGINE).
_D_H___n_e_w___m_e_t_h_o_d_(_) returns NULL and sets an error code that can be obtained by _E_R_R___g_e_t___e_r_r_o_r(3) if the allocation fails. Otherwise it returns a pointer to the newly allocated structure.
_D_H___s_e_t___d_e_f_a_u_l_t___o_p_e_n_s_s_l___m_e_t_h_o_d_(_) and _D_H___g_e_t___d_e_f_a_u_l_t___o_p_e_n_s_s_l___m_e_t_h_o_d_(_) replaced _D_H___s_e_t___d_e_f_a_u_l_t___m_e_t_h_o_d_(_) and _D_H___g_e_t___d_e_f_a_u_l_t___m_e_t_h_o_d_(_) respectively, and _D_H___s_e_t___m_e_t_h_o_d_(_) and _D_H___n_e_w___m_e_t_h_o_d_(_) were altered to use EENNGGIINNEEs rather than DDHH__MMEETTHHOODDs during development of the engine version of OpenSSL 0.9.6. For 0.9.7, the handling of defaults in the ENGINE API was restructured so that this change was reversed, and behaviour of the other functions resembled more closely the previous behaviour. The behaviour of defaults in the ENGINE API now transparently overrides the behaviour of defaults in the DH API without requiring changing these function prototypes.