ecjpake_zkp_write() function
Syntax
static int ecjpake_zkp_write(const mbedtls_md_type_t md_type,
const mbedtls_ecp_group *grp,
const int pf,
const mbedtls_ecp_point *G,
const mbedtls_mpi *x,
const mbedtls_ecp_point *X,
const char *id,
unsigned char **p,
const unsigned char *end,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng);