/* Return an MPI (or opaque MPI) described by NAME and the context EC. If COPY is true a copy is returned, if not a const MPI may be returned. In any case mpi_free must be used. */ gcry_mpi_t _gcry_ecc_get_mpi (const char *name, mpi_ec_t ec, int copy) { if (!*name) return NULL; if (!strcmp (name, "p") && ec->p) return mpi_is_const (ec->p) && !copy? ec->p : mpi_copy (ec->p); if (!strcmp (name, "a") && ec->a) return mpi_is_const (ec->a) && !copy? ec->a : mpi_copy (ec->a); if (!strcmp (name, "b") && ec->b) return mpi_is_const (ec->b) && !copy? ec->b : mpi_copy (ec->b); if (!strcmp (name, "n") && ec->n) return mpi_is_const (ec->n) && !copy? ec->n : mpi_copy (ec->n); if (!strcmp (name, "d") && ec->d) return mpi_is_const (ec->d) && !copy? ec->d : mpi_copy (ec->d); /* Return a requested point coordinate. */ if (!strcmp (name, "g.x") && ec->G && ec->G->x) return mpi_is_const (ec->G->x) && !copy? ec->G->x : mpi_copy (ec->G->x); if (!strcmp (name, "g.y") && ec->G && ec->G->y) return mpi_is_const (ec->G->y) && !copy? ec->G->y : mpi_copy (ec->G->y); if (!strcmp (name, "q.x") && ec->Q && ec->Q->x) return mpi_is_const (ec->Q->x) && !copy? ec->Q->x : mpi_copy (ec->Q->x); if (!strcmp (name, "q.y") && ec->Q && ec->Q->y) return mpi_is_const (ec->G->y) && !copy? ec->Q->y : mpi_copy (ec->Q->y); /* If the base point has been requested, return it in standard encoding. */ if (!strcmp (name, "g") && ec->G) return _gcry_mpi_ec_ec2os (ec->G, ec); /* If the public key has been requested, return it by default in standard uncompressed encoding or if requested in other encodings. */ if (*name == 'q' && (!name[1] || name[1] == '@')) { /* If only the private key is given, compute the public key. */ if (!ec->Q) ec->Q = _gcry_ecc_compute_public (NULL, ec, NULL, NULL); if (!ec->Q) return NULL; if (name[1] != '@') return _gcry_mpi_ec_ec2os (ec->Q, ec); if (!strcmp (name+2, "eddsa") && ec->model == MPI_EC_TWISTEDEDWARDS) { unsigned char *encpk; unsigned int encpklen; if (!_gcry_ecc_eddsa_encodepoint (ec->Q, ec, NULL, NULL, &encpk, &encpklen)) return mpi_set_opaque (NULL, encpk, encpklen*8); } } return NULL; }
gcry_mpi_t _gcry_mpi_ec_get_mpi (const char *name, gcry_ctx_t ctx, int copy) { mpi_ec_t ec = _gcry_ctx_get_pointer (ctx, CONTEXT_TYPE_EC); if (!strcmp (name, "p") && ec->p) return mpi_is_const (ec->p) && !copy? ec->p : mpi_copy (ec->p); if (!strcmp (name, "a") && ec->a) return mpi_is_const (ec->a) && !copy? ec->a : mpi_copy (ec->a); if (!strcmp (name, "b") && ec->b) return mpi_is_const (ec->b) && !copy? ec->b : mpi_copy (ec->b); if (!strcmp (name, "n") && ec->n) return mpi_is_const (ec->n) && !copy? ec->n : mpi_copy (ec->n); if (!strcmp (name, "d") && ec->d) return mpi_is_const (ec->d) && !copy? ec->d : mpi_copy (ec->d); /* Return a requested point coordinate. */ if (!strcmp (name, "g.x") && ec->G && ec->G->x) return mpi_is_const (ec->G->x) && !copy? ec->G->x : mpi_copy (ec->G->x); if (!strcmp (name, "g.y") && ec->G && ec->G->y) return mpi_is_const (ec->G->y) && !copy? ec->G->y : mpi_copy (ec->G->y); if (!strcmp (name, "q.x") && ec->Q && ec->Q->x) return mpi_is_const (ec->Q->x) && !copy? ec->Q->x : mpi_copy (ec->Q->x); if (!strcmp (name, "q.y") && ec->Q && ec->Q->y) return mpi_is_const (ec->G->y) && !copy? ec->Q->y : mpi_copy (ec->Q->y); /* If a point has been requested, return it in standard encoding. */ if (!strcmp (name, "g") && ec->G) return _gcry_mpi_ec_ec2os (ec->G, ec); if (!strcmp (name, "q")) { /* If only the private key is given, compute the public key. */ if (!ec->Q && ec->d && ec->G && ec->p && ec->a) { ec->Q = gcry_mpi_point_new (0); _gcry_mpi_ec_mul_point (ec->Q, ec->d, ec->G, ec); } if (ec->Q) return _gcry_mpi_ec_ec2os (ec->Q, ec); } return NULL; }