in src/crypto/openssl.rs [41:46]
fn to_pkey(&self) -> Result<PKey<Public>> {
let mut bn_ctx = BigNumContext::new()?;
let point = EcPoint::from_bytes(&GROUP_P256, &self.raw_pub_key, &mut bn_ctx)?;
let ec = EcKey::from_public_key(&GROUP_P256, &point)?;
PKey::from_ec_key(ec).map_err(std::convert::Into::into)
}