diff options
Diffstat (limited to 'moon-abe/pbc-0.5.14/include/pbc_curve.h')
-rw-r--r-- | moon-abe/pbc-0.5.14/include/pbc_curve.h | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/moon-abe/pbc-0.5.14/include/pbc_curve.h b/moon-abe/pbc-0.5.14/include/pbc_curve.h new file mode 100644 index 00000000..9a86903d --- /dev/null +++ b/moon-abe/pbc-0.5.14/include/pbc_curve.h @@ -0,0 +1,79 @@ +// A subgroup of the group of points on an elliptic curve. +// Also used to represent quotient groups. +// +// We use the field_t structure even though E(K) is a group. Addition and +// multiplication both refer to the group operation. + +// Requires: +// * stdio.h +// * gmp.h +// * field.h +#ifndef __PBC_CURVE_H__ +#define __PBC_CURVE_H__ + +// Some initialization functions take an order parameter. This is meant to +// be the order of the subgroup, but might actually be the order of the twist. +// Certain routines initialize a curve, test a random point to see if it has +// the correct order, and if not, immediately twist the curve so that it does. +// TODO: Move such code into curve.c, so 'order' is always accurate. + +// If cofac != NULL, then the field_t represents the subgroup of +// order = #E(K) / cofac. +// +// If not, and order = #E(K) then the field_t represents the entire E(K). +// +// Otherwise, if order is a factor of #E(K), then the field_t represents +// the quotient group of that order, namely E(K)/(#E(K)/order). No attempt is +// made to standardize the coset representative. This mode is useful for the +// Tate pairing (see thesis), where any coset representative of G2 suffices +// during the pairing computation. + +// Initialize a subgroup of points on the curve Y^2 = X^3 + b. +void field_init_curve_b(field_ptr f, element_ptr b, mpz_t order, mpz_t cofac); + +// Initialize a subgroup of points on the curve with the given j-invariant. +void field_init_curve_j(field_t f, element_ptr j, mpz_t order, mpz_t cofac); + +// Initialize a subgroup of points on the curve Y^2 = X^3 + a X + b. +void field_init_curve_ab(field_ptr f, element_ptr a, element_ptr b, mpz_t order, mpz_t cofac); + +// Reinitialize as the subgroup of points on the twist curve. +// Requires j-invariant of the original curve != 0, 1728. +// Mangles f, thus existing points of f become invalid. +// TODO: Refactor so we can remove this from the interface. +void field_reinit_curve_twist(field_t f); + +// Compute trace of Frobenius at q^n given trace at q. +void pbc_mpz_trace_n(mpz_t res, mpz_t q, mpz_t trace, int n); + +// Given q, t such that #E(F_q) = q - t + 1, compute #E(F_q^k). +void pbc_mpz_curve_order_extn(mpz_t res, mpz_t q, mpz_t t, int k); + +void field_init_curve_with_map(field_ptr cnew, field_ptr c, + field_ptr dstfield, fieldmap map); + +void field_init_curve_ab_map(field_t cnew, field_t c, + fieldmap map, field_ptr mapdest, + mpz_t ordernew, mpz_t cofacnew); + +void field_curve_use_random_solvefory(field_ptr f); + +void field_curve_set_quotient_cmp(field_ptr c, mpz_t quotient_cmp); + +#pragma GCC visibility push(hidden) +// Internal: + +element_ptr curve_x_coord(element_t e); +element_ptr curve_y_coord(element_t e); +element_ptr curve_a_coeff(element_t e); +element_ptr curve_b_coeff(element_t e); +element_ptr curve_field_a_coeff(field_t f); +element_ptr curve_field_b_coeff(field_t f); + +void curve_from_x(element_ptr e, element_t x); +void curve_set_si(element_t R, long int x, long int y); +void curve_set_gen_no_cofac(element_ptr a); + +#pragma GCC visibility pop + +#endif //__PBC_CURVE_H__ |