from ecp_curves.c:584
static int ecp_group_load( mbedtls_ecp_group *grp,
const mbedtls_mpi_uint *p,
size_t plen,
const mbedtls_mpi_uint *a,
size_t alen,
const mbedtls_mpi_uint *b,
size_t blen,
const mbedtls_mpi_uint *gx,
size_t gxlen,
const mbedtls_mpi_uint *gy,
size_t gylen,
const mbedtls_mpi_uint *n,
size_t nlen);