Function bigNumToBase64Url

fdbrpc/JsonWebKeySet.cpp:169–174

#define RSA_DECLARE_DECODED_OPTIONAL_BN_MEMBER(member) DECL_DECODED_BN_MEMBER_OPTIONAL(member, "RSA")

StringRef bigNumToBase64Url(Arena& arena, const BIGNUM* bn) {
	auto len = BN_num_bytes(bn);
	auto buf = new (arena) uint8_t[len];
	::BN_bn2bin(bn, buf);
	return base64url::encode(arena, StringRef(buf, len));
}

Optional<PublicOrPrivateKey> parseEcP256Key(StringRef b64x, StringRef b64y, Optional<StringRef> b64d, int keyIndex) {
	auto arena = Arena();