EC_GFp_simple_method(3) OpenSSL EC_GFp_simple_method(3) NNAAMMEE EC_GFp_simple_method, EC_GFp_mont_method, EC_GFp_nist_method, EC_GFp_nistp224_method, EC_GFp_nistp256_method, EC_GFp_nistp521_method, EC_GF2m_simple_method, EC_METHOD_get_field_type - Functions for obtain- ing EECC__MMEETTHHOODD objects. SSYYNNOOPPSSIISS #include const EC_METHOD *EC_GFp_simple_method(void); const EC_METHOD *EC_GFp_mont_method(void); const EC_METHOD *EC_GFp_nist_method(void); const EC_METHOD *EC_GFp_nistp224_method(void); const EC_METHOD *EC_GFp_nistp256_method(void); const EC_METHOD *EC_GFp_nistp521_method(void); const EC_METHOD *EC_GF2m_simple_method(void); int EC_METHOD_get_field_type(const EC_METHOD *meth); DDEESSCCRRIIPPTTIIOONN The Elliptic Curve library provides a number of different implementa- tions through a single common interface. When constructing a curve using EC_GROUP_new (see _E_C___G_R_O_U_P___n_e_w(3)) an implementation method must be provided. The functions described here all return a const pointer to an EECC__MMEETTHHOODD structure that can be passed to EC_GROUP_NEW. It is impor- tant that the correct implementation type for the form of curve selected is used. For F2^m curves there is only one implementation choice, i.e. EC_GF2_simple_method. For Fp curves the lowest common denominator implementation is the EC_GFp_simple_method implementation. All other implementations are based on this one. EC_GFp_mont_method builds on EC_GFp_simple_method but adds the use of montgomery multiplication (see _B_N___m_o_d___m_u_l___m_o_n_t_- _g_o_m_e_r_y(3)). EC_GFp_nist_method offers an implementation optimised for use with NIST recommended curves (NIST curves are available through EC_GROUP_new_by_curve_name as described in _E_C___G_R_O_U_P___n_e_w(3)). The functions EC_GFp_nistp224_method, EC_GFp_nistp256_method and EC_GFp_nistp521_method offer 64 bit optimised implementations for the NIST P224, P256 and P521 curves respectively. Note, however, that these implementations are not available on all platforms. EC_METHOD_get_field_type identifies what type of field the EC_METHOD structure supports, which will be either F2^m or Fp. If the field type is Fp then the value NNIIDD__XX99__6622__pprriimmee__ffiieelldd is returned. If the field type is F2^m then the value NNIIDD__XX99__6622__cchhaarraacctteerriissttiicc__ttwwoo__ffiieelldd is returned. These values are defined in the obj_mac.h header file. RREETTUURRNN VVAALLUUEESS All EC_GFp* functions and EC_GF2m_simple_method always return a const pointer to an EC_METHOD structure. EC_METHOD_get_field_type returns an integer that identifies the type of field the EC_METHOD structure supports. SSEEEE AALLSSOO _c_r_y_p_t_o(3), _e_c(3), _E_C___G_R_O_U_P___n_e_w(3), _E_C___G_R_O_U_P___c_o_p_y(3), _E_C___P_O_I_N_T___n_e_w(3), _E_C___P_O_I_N_T___a_d_d(3), _E_C___K_E_Y___n_e_w(3), _d_2_i___E_C_P_K_P_a_r_a_m_e_t_e_r_s(3), _B_N___m_o_d___m_u_l___m_o_n_t_- _g_o_m_e_r_y(3) 1.0.2u 2019-12-20 EC_GFp_simple_method(3)