BN_mod_sqr_reciprocal
if (!BN_mod_sqr_reciprocal(aa, val[0], recp, ctx))
if (!BN_mod_sqr_reciprocal(r, r, recp, ctx))
if (!BN_mod_sqr_reciprocal(r, r, recp, ctx))
int BN_mod_sqr_reciprocal(BIGNUM *r, const BIGNUM *x, BN_RECP_CTX *recp,