update: switch to msgpack. I didn't know nlohmann already had that, it's way better for this case

bare_minimum_crypto/cpp/bmc_test.cpp

@@ -59,15 +59,15 @@ public:
 			{"payload_b64", payload_b64},
 		};
 		
-		const auto cert_s = j.dump ();
+		const auto cert = json::to_msgpack (j);
 		
 		vector <uint8_t> sig;
 		sig.resize (crypto_sign_BYTES);
 		
-		crypto_sign_detached (sig.data (), nullptr, (const uint8_t *)cert_s.data (), cert_s.size (), sk.data ());
+		crypto_sign_detached (sig.data (), nullptr, cert.data (), cert.size (), sk.data ());
 		
 		return ExpiringSignature {
-			cert_s,
+			cert,
 			sig,
 		};
 	}
@@ -129,12 +129,6 @@ int happy_path () {
 		}
 	}
 	
-	{
-		cerr << "Cert:" << endl;
-		cerr << cert.cert_s << endl;
-		cerr << base64_encode (cert.sig) << endl;
-	}
-	
 	// The receiver verifies the data by the root public key,
 	// even though the receiver has never seen the sub-key.
 	
@@ -142,16 +136,16 @@ int happy_path () {
 	
 	const json j {
 		{"cert", {
-			{"sig_b64", base64_encode (cert.sig)},
+			{"sig", json::binary (cert.sig)},
-			{"payload_s", cert.cert_s},
+			{"cert", json::binary (cert.cert)},
 		}},
 		{"data", {
-			{"sig_b64", base64_encode (signed_data.sig)},
+			{"sig", json::binary (signed_data.sig)},
-			{"payload_s", signed_data.cert_s},
+			{"cert", json::binary (signed_data.cert)},
 		}},
 	};
 	
-	auto verified_opt = Receiver::verify_cert_and_data (root_pubkey, j.dump ());
+	auto verified_opt = Receiver::verify_cert_and_data (root_pubkey, json::to_msgpack (j));
 	if (! verified_opt) {
 		cerr << "Receiver couldn't verify cert and data" << endl;
 		return 1;

bare_minimum_crypto/cpp/expiring_signature.cpp

@@ -4,7 +4,7 @@ namespace BareMinimumCrypto {
 	// C++ nonsense
 	bool ExpiringSignature::operator == (const ExpiringSignature & o) const {
 		return
-			cert_s == o.cert_s &&
+			cert == o.cert &&
 			sig == o.sig
 		;
 	}

bare_minimum_crypto/cpp/expiring_signature.h

@@ -10,7 +10,8 @@ namespace BareMinimumCrypto {
 	using namespace std;
 	
 	struct ExpiringSignature {
-		string cert_s;
+		// Payload is contained in here
+		vector <uint8_t> cert;
 		vector <uint8_t> sig;
 		
 		bool operator == (const ExpiringSignature & o) const;

bare_minimum_crypto/cpp/receiver.cpp

@@ -29,14 +29,14 @@ namespace BareMinimumCrypto::Receiver {
 		
 		if (crypto_sign_verify_detached (
 			sig.sig.data (),
-			(const uint8_t *)sig.cert_s.data (),
+			sig.cert.data (),
-			sig.cert_s.size (),
+			sig.cert.size (),
 			pubkey.data ()
 		) != 0) {
 			return nullopt;
 		}
 		
-		const json j = json::parse (sig.cert_s);
+		const json j = json::from_msgpack (sig.cert);
 		
 		const TimeRange tr {
 			j ["not_before"],
@@ -91,33 +91,33 @@ namespace BareMinimumCrypto::Receiver {
 	
 	optional <vector <uint8_t>> try_verify_cert_and_data (
 		const vector <uint8_t> & root_pubkey,
-		const string & json_string,
+		const vector <uint8_t> & msgpack,
 		Instant now
 	) {
-		const json j = json::parse (json_string);
+		const auto j = json::from_msgpack (msgpack);
 		
 		ExpiringSignature cert;
 		
-		cert.sig = *base64_decode (j ["cert"]["sig_b64"]);
+		cert.sig = j ["cert"]["sig"].get_binary ();
-		cert.cert_s = j ["cert"]["payload_s"];
+		cert.cert = j ["cert"]["cert"].get_binary ();
 		
 		auto subkey_opt = verify_signed_data (root_pubkey, cert, now);
 		const auto subkey = std::move (*subkey_opt);
 		
 		ExpiringSignature data;
 		
-		data.sig = *base64_decode (j ["data"]["sig_b64"]);
+		data.sig = j ["data"]["sig"].get_binary ();
-		data.cert_s = j ["data"]["payload_s"];
+		data.cert = j ["data"]["cert"].get_binary ();
 		
 		return verify_signed_data (subkey, data, now);
 	}
 	
 	optional <vector <uint8_t>> verify_cert_and_data (
 		const vector <uint8_t> & root_pubkey,
-		const string & json_string
+		const vector <uint8_t> & msgpack
 	) {
 		try {
-			return try_verify_cert_and_data (root_pubkey, json_string, Instant::now ());
+			return try_verify_cert_and_data (root_pubkey, msgpack, Instant::now ());
 		}
 		catch (json::exception &) {
 			return nullopt;

bare_minimum_crypto/cpp/receiver.h

@@ -32,6 +32,6 @@ namespace BareMinimumCrypto::Receiver {
 	
 	optional <vector <uint8_t>> verify_cert_and_data (
 		const vector <uint8_t> & root_pubkey,
-		const string & json_string
+		const vector <uint8_t> & msgpack
 	);
 }