diff --git a/src/Cryptography/AES.h b/src/Cryptography/AES.h
index c245e9d..2a00d06 100644
--- a/src/Cryptography/AES.h
+++ b/src/Cryptography/AES.h
@@ -11,7 +11,7 @@ namespace RNS { namespace Cryptography {
 	class AES_128_CBC {
 
 	public:
-		static inline Bytes encrypt(const Bytes &plaintext, const Bytes &key, const Bytes &iv) {
+		static inline const Bytes encrypt(const Bytes &plaintext, const Bytes &key, const Bytes &iv) {
 			CBC<AES128> cbc;
 			cbc.setKey(key.data(), key.size());
 			cbc.setIV(iv.data(), iv.size());
@@ -20,7 +20,7 @@ namespace RNS { namespace Cryptography {
 			return ciphertext;
 		}
 
-		static inline Bytes decrypt(const Bytes &ciphertext, const Bytes &key, const Bytes &iv) {
+		static inline const Bytes decrypt(const Bytes &ciphertext, const Bytes &key, const Bytes &iv) {
 			CBC<AES128> cbc;
 			cbc.setKey(key.data(), key.size());
 			cbc.setIV(iv.data(), iv.size());
diff --git a/src/Cryptography/Ed25519.h b/src/Cryptography/Ed25519.h
index 0c46665..aca68f2 100644
--- a/src/Cryptography/Ed25519.h
+++ b/src/Cryptography/Ed25519.h
@@ -30,7 +30,7 @@ namespace RNS { namespace Cryptography {
 			return Ptr(new Ed25519PublicKey(publicKey));
 		}
 
-		inline Bytes public_bytes() {
+		inline const Bytes &public_bytes() {
 			return _publicKey;
 		}
 
@@ -75,7 +75,7 @@ namespace RNS { namespace Cryptography {
 			return Ptr(new Ed25519PrivateKey(privateKey));
 		}
 
-		inline Bytes private_bytes() {
+		inline const Bytes &private_bytes() {
 			return _privateKey;
 		}
 
@@ -84,7 +84,7 @@ namespace RNS { namespace Cryptography {
 			return Ed25519PublicKey::from_public_bytes(_publicKey);
 		}
 
-		inline Bytes sign(const Bytes &message) {
+		inline const Bytes sign(const Bytes &message) {
 			//zreturn _sk.sign(message);
 			Bytes signature;
 			Ed25519::sign(signature.writable(64), _privateKey.data(), _publicKey.data(), message.data(), message.size());
diff --git a/src/Cryptography/Fernet.cpp b/src/Cryptography/Fernet.cpp
index 13e755c..306d381 100644
--- a/src/Cryptography/Fernet.cpp
+++ b/src/Cryptography/Fernet.cpp
@@ -49,7 +49,7 @@ bool Fernet::verify_hmac(const Bytes &token) {
 	return (received_hmac == expected_hmac);
 }
 
-Bytes Fernet::encrypt(const Bytes &data) {
+const Bytes Fernet::encrypt(const Bytes &data) {
 
 	debug("Fernet::encrypt: plaintext length: " + std::to_string(data.size()));
 	Bytes iv = random(16);
@@ -76,7 +76,7 @@ Bytes Fernet::encrypt(const Bytes &data) {
 }
 
 
-Bytes Fernet::decrypt(const Bytes &token) {
+const Bytes Fernet::decrypt(const Bytes &token) {
 
 	debug("Fernet::decrypt: token length: " + std::to_string(token.size()));
 	if (token.size() < 48) {
diff --git a/src/Cryptography/Fernet.h b/src/Cryptography/Fernet.h
index a8a8a1d..5869c25 100644
--- a/src/Cryptography/Fernet.h
+++ b/src/Cryptography/Fernet.h
@@ -22,7 +22,7 @@ namespace RNS { namespace Cryptography {
 		static const uint8_t FERNET_OVERHEAD  = 48; // Bytes
 
 	public:
-		static inline Bytes generate_key() { return random(32); }
+		static inline const Bytes generate_key() { return random(32); }
 
 	public:
 		Fernet(const Bytes &key);
@@ -30,8 +30,8 @@ namespace RNS { namespace Cryptography {
 
 	public:
 		bool verify_hmac(const Bytes &token);
-		Bytes encrypt(const Bytes &data);
-		Bytes decrypt(const Bytes &token);
+		const Bytes encrypt(const Bytes &data);
+		const Bytes decrypt(const Bytes &token);
 
 	private:
 		Bytes _signing_key;
diff --git a/src/Cryptography/HKDF.cpp b/src/Cryptography/HKDF.cpp
index f614131..2299749 100644
--- a/src/Cryptography/HKDF.cpp
+++ b/src/Cryptography/HKDF.cpp
@@ -5,7 +5,7 @@
 
 using namespace RNS;
 
-Bytes RNS::Cryptography::hkdf(size_t length, const Bytes &derive_from, const Bytes &salt /*= {Bytes::NONE}*/, const Bytes &context /*= {Bytes::NONE}*/) {
+const Bytes RNS::Cryptography::hkdf(size_t length, const Bytes &derive_from, const Bytes &salt /*= {Bytes::NONE}*/, const Bytes &context /*= {Bytes::NONE}*/) {
 
 	if (length <= 0) {
 		throw std::invalid_argument("Invalid output key length");
diff --git a/src/Cryptography/HKDF.h b/src/Cryptography/HKDF.h
index f3f9039..e8a7ca5 100644
--- a/src/Cryptography/HKDF.h
+++ b/src/Cryptography/HKDF.h
@@ -4,6 +4,6 @@
 
 namespace RNS { namespace Cryptography {
 
-	Bytes hkdf(size_t length, const Bytes &derive_from, const Bytes &salt = {Bytes::NONE}, const Bytes &context = {Bytes::NONE});
+	const Bytes hkdf(size_t length, const Bytes &derive_from, const Bytes &salt = {Bytes::NONE}, const Bytes &context = {Bytes::NONE});
 
 } }
diff --git a/src/Cryptography/HMAC.h b/src/Cryptography/HMAC.h
index 980fc11..cc09811 100644
--- a/src/Cryptography/HMAC.h
+++ b/src/Cryptography/HMAC.h
@@ -99,7 +99,7 @@ namespace RNS { namespace Cryptography {
 	msg: bytes or buffer, Input message.
 	digest: The underlying hash algorithm to use.
 	*/
-	inline Bytes digest(const Bytes &key, const Bytes &msg, HMAC::Digest digest = HMAC::DIGEST_SHA256) {
+	inline const Bytes digest(const Bytes &key, const Bytes &msg, HMAC::Digest digest = HMAC::DIGEST_SHA256) {
 		HMAC hmac(key, msg, digest);
 		hmac.update(msg);
 		return hmac.digest();
diff --git a/src/Cryptography/Hashes.cpp b/src/Cryptography/Hashes.cpp
index e656fb6..7f9521e 100644
--- a/src/Cryptography/Hashes.cpp
+++ b/src/Cryptography/Hashes.cpp
@@ -14,7 +14,7 @@ uses Python's internal SHA-256 implementation. All SHA-256
 calls in RNS end up here.
 */
 
-Bytes RNS::Cryptography::sha256(const Bytes &data) {
+const Bytes RNS::Cryptography::sha256(const Bytes &data) {
 	//extreme("Cryptography::sha256: data: " + data.toHex() );
 	SHA256 digest;
 	digest.reset();
@@ -25,7 +25,7 @@ Bytes RNS::Cryptography::sha256(const Bytes &data) {
 	return hash;
 }
 
-Bytes RNS::Cryptography::sha512(const Bytes &data) {
+const Bytes RNS::Cryptography::sha512(const Bytes &data) {
 	SHA512 digest;
 	digest.reset();
 	digest.update(data.data(), data.size());
diff --git a/src/Cryptography/Hashes.h b/src/Cryptography/Hashes.h
index 8c0b913..e12d1c6 100644
--- a/src/Cryptography/Hashes.h
+++ b/src/Cryptography/Hashes.h
@@ -6,7 +6,7 @@
 
 namespace RNS { namespace Cryptography {
 
-	Bytes sha256(const Bytes &data);
-	Bytes sha512(const Bytes &data);
+	const Bytes sha256(const Bytes &data);
+	const Bytes sha512(const Bytes &data);
 
 } }
diff --git a/src/Cryptography/PKCS7.h b/src/Cryptography/PKCS7.h
index c508406..aad906d 100644
--- a/src/Cryptography/PKCS7.h
+++ b/src/Cryptography/PKCS7.h
@@ -13,13 +13,13 @@ namespace RNS { namespace Cryptography {
 
 		static const size_t BLOCKSIZE = 16;
 
-		static inline Bytes pad(const Bytes &data, size_t bs = BLOCKSIZE) {
+		static inline const Bytes pad(const Bytes &data, size_t bs = BLOCKSIZE) {
 			Bytes padded(data);
 			inplace_pad(padded, bs);
 			return padded;
 		}
 
-		static inline Bytes unpad(const Bytes &data, size_t bs = BLOCKSIZE) {
+		static inline const Bytes unpad(const Bytes &data, size_t bs = BLOCKSIZE) {
 			Bytes unpadded(data);
 			inplace_unpad(unpadded, bs);
 			return unpadded;
diff --git a/src/Cryptography/Random.h b/src/Cryptography/Random.h
index 3a4b955..5454fc7 100644
--- a/src/Cryptography/Random.h
+++ b/src/Cryptography/Random.h
@@ -8,7 +8,7 @@
 namespace RNS { namespace Cryptography {
 
     // return vector specified length of random bytes
-	inline Bytes random(size_t length) {
+	inline const Bytes random(size_t length) {
         Bytes rand;
         RNG.rand(rand.writable(length), length);
         return rand;
diff --git a/src/Cryptography/X25519.h b/src/Cryptography/X25519.h
index bf1832d..27cb745 100644
--- a/src/Cryptography/X25519.h
+++ b/src/Cryptography/X25519.h
@@ -111,11 +111,11 @@ namespace RNS { namespace Cryptography {
 		}
 
 /*
-		inline Bytes private_bytes() {
+		inline const Bytes private_bytes() {
 			return _pack_number(_a);
 		}
 */
-		inline Bytes private_bytes() {
+		inline const Bytes &private_bytes() {
 			return _privateKey;
 		}
 
@@ -130,7 +130,7 @@ namespace RNS { namespace Cryptography {
 		}
 
 /*
-		inline Bytes exchange(const Bytes &peer_public_key) {
+		inline const Bytes exchange(const Bytes &peer_public_key) {
 			if isinstance(peer_public_key, bytes):
 				peer_public_key = X25519PublicKey.from_public_bytes(peer_public_key)
 
@@ -168,7 +168,7 @@ namespace RNS { namespace Cryptography {
 			return shared
 		}
 */
-		inline Bytes exchange(const Bytes &peer_public_key) {
+		inline const Bytes exchange(const Bytes &peer_public_key) {
 			debug("X25519PublicKey::exchange: public key:       " + _publicKey.toHex());
 			debug("X25519PublicKey::exchange: peer public key:  " + peer_public_key.toHex());
 			debug("X25519PublicKey::exchange: pre private key:  " + _privateKey.toHex());
diff --git a/src/Destination.cpp b/src/Destination.cpp
index f755e28..25ba5df 100644
--- a/src/Destination.cpp
+++ b/src/Destination.cpp
@@ -314,7 +314,7 @@ Encrypts information for ``RNS.Destination.SINGLE`` or ``RNS.Destination.GROUP``
 :param plaintext: A *bytes-like* containing the plaintext to be encrypted.
 :raises: ``ValueError`` if destination does not hold a necessary key for encryption.
 */
-Bytes Destination::encrypt(const Bytes &data) {
+const Bytes Destination::encrypt(const Bytes &data) {
 	assert(_object);
 	debug("Destination::encrypt: encrypting data...");
 
@@ -348,7 +348,7 @@ Decrypts information for ``RNS.Destination.SINGLE`` or ``RNS.Destination.GROUP``
 :param ciphertext: *Bytes* containing the ciphertext to be decrypted.
 :raises: ``ValueError`` if destination does not hold a necessary key for decryption.
 */
-Bytes Destination::decrypt(const Bytes &data) {
+const Bytes Destination::decrypt(const Bytes &data) {
 	assert(_object);
 	debug("Destination::decrypt: decrypting data...");
 
@@ -382,7 +382,7 @@ Signs information for ``RNS.Destination.SINGLE`` type destination.
 :param message: *Bytes* containing the message to be signed.
 :returns: A *bytes-like* containing the message signature, or *None* if the destination could not sign the message.
 */
-Bytes Destination::sign(const Bytes &message) {
+const Bytes Destination::sign(const Bytes &message) {
 	assert(_object);
 	if (_object->_type == SINGLE && _object->_identity) {
 		return _object->_identity.sign(message);
diff --git a/src/Destination.h b/src/Destination.h
index 12635bc..5aee89f 100644
--- a/src/Destination.h
+++ b/src/Destination.h
@@ -144,16 +144,16 @@ namespace RNS {
 		void receive(const Packet &packet);
 		void incoming_link_request(const Bytes &data, const Packet &packet);
 
-		Bytes encrypt(const Bytes &data);
-		Bytes decrypt(const Bytes &data);
-		Bytes sign(const Bytes &message);
+		const Bytes encrypt(const Bytes &data);
+		const Bytes decrypt(const Bytes &data);
+		const Bytes sign(const Bytes &message);
 
 		// getters/setters
 		inline Type::Destination::types type() const { assert(_object); return _object->_type; }
 		inline Type::Destination::directions direction() const { assert(_object); return _object->_direction; }
 		inline Type::Destination::proof_strategies proof_strategy() const { assert(_object); return _object->_proof_strategy; }
-		inline Bytes hash() const { assert(_object); return _object->_hash; }
-		inline Bytes link_id() const { assert(_object); return _object->_link_id; }
+		inline const Bytes &hash() const { assert(_object); return _object->_hash; }
+		inline const Bytes &link_id() const { assert(_object); return _object->_link_id; }
 		inline uint16_t mtu() const { assert(_object); return _object->_mtu; }
 		inline void mtu(uint16_t mtu) { assert(_object); _object->_mtu = mtu; }
 		inline Type::Link::status status() const { assert(_object); return _object->_status; }
diff --git a/src/Identity.cpp b/src/Identity.cpp
index c80ba3e..6414bd2 100644
--- a/src/Identity.cpp
+++ b/src/Identity.cpp
@@ -132,7 +132,7 @@ Encrypts information for the identity.
 :returns: Ciphertext token as *bytes*.
 :raises: *KeyError* if the instance does not hold a public key.
 */
-Bytes Identity::encrypt(const Bytes &plaintext) {
+const Bytes Identity::encrypt(const Bytes &plaintext) {
 	assert(_object);
 	debug("Identity::encrypt: encrypting data...");
 	if (!_object->_pub) {
@@ -172,7 +172,7 @@ Decrypts information for the identity.
 :returns: Plaintext as *bytes*, or *None* if decryption fails.
 :raises: *KeyError* if the instance does not hold a private key.
 */
-Bytes Identity::decrypt(const Bytes &ciphertext_token) {
+const Bytes Identity::decrypt(const Bytes &ciphertext_token) {
 	assert(_object);
 	debug("Identity::decrypt: decrypting data...");
 	if (!_object->_prv) {
@@ -226,7 +226,7 @@ Signs information by the identity.
 :returns: Signature as *bytes*.
 :raises: *KeyError* if the instance does not hold a private key.
 */
-Bytes Identity::sign(const Bytes &message) {
+const Bytes Identity::sign(const Bytes &message) {
 	assert(_object);
 	if (!_object->_sig_prv) {
 		throw std::runtime_error("Signing failed because identity does not hold a private key");
diff --git a/src/Identity.h b/src/Identity.h
index 87c7bd4..d7867ca 100644
--- a/src/Identity.h
+++ b/src/Identity.h
@@ -48,7 +48,7 @@ namespace RNS {
 		/*
 		:returns: The public key as *bytes*
 		*/
-		inline Bytes get_public_key() {
+		inline const Bytes get_public_key() {
 			assert(_object);
 			return _object->_pub_bytes + _object->_sig_pub_bytes;
 		}
@@ -65,7 +65,7 @@ namespace RNS {
 		:param data: Data to be hashed as *bytes*.
 		:returns: SHA-256 hash as *bytes*
 		*/
-		static inline Bytes full_hash(const Bytes &data) {
+		static inline const Bytes full_hash(const Bytes &data) {
 			return Cryptography::sha256(data);
 		}
 		/*
@@ -74,7 +74,7 @@ namespace RNS {
 		:param data: Data to be hashed as *bytes*.
 		:returns: Truncated SHA-256 hash as *bytes*
 		*/
-		static inline Bytes truncated_hash(const Bytes &data) {
+		static inline const Bytes truncated_hash(const Bytes &data) {
 			//return Identity.full_hash(data)[:(Identity.TRUNCATED_HASHLENGTH//8)]
 			return full_hash(data).left(Type::Identity::TRUNCATED_HASHLENGTH/8);
 		}
@@ -84,18 +84,18 @@ namespace RNS {
 		:param data: Data to be hashed as *bytes*.
 		:returns: Truncated SHA-256 hash of random data as *bytes*
 		*/
-		static inline Bytes get_random_hash() {
+		static inline const Bytes get_random_hash() {
 			return truncated_hash(Cryptography::random(Type::Identity::TRUNCATED_HASHLENGTH/8));
 		}
 
 		static bool validate_announce(const Packet &packet);
 
-		inline Bytes get_salt() { assert(_object); return _object->_hash; }
-		inline Bytes get_context() { return {Bytes::NONE}; }
+		inline const Bytes get_salt() { assert(_object); return _object->_hash; }
+		inline const Bytes get_context() { return {Bytes::NONE}; }
 
-		Bytes encrypt(const Bytes &plaintext);
-		Bytes decrypt(const Bytes &ciphertext_token);
-		Bytes sign(const Bytes &message);
+		const Bytes encrypt(const Bytes &plaintext);
+		const Bytes decrypt(const Bytes &ciphertext_token);
+		const Bytes sign(const Bytes &message);
 		bool validate(const Bytes &signature, const Bytes &message);
 		// CBA following default for reference value requires inclusiion of header
 		//void prove(const Packet &packet, const Destination &destination = {Type::NONE});
@@ -103,11 +103,11 @@ namespace RNS {
 		void prove(const Packet &packet);
 
 		// getters/setters
-		inline Bytes encryptionPrivateKey() const { assert(_object); return _object->_prv_bytes; }
-		inline Bytes signingPrivateKey() const { assert(_object); return _object->_sig_prv_bytes; }
-		inline Bytes encryptionPublicKey() const { assert(_object); return _object->_prv_bytes; }
-		inline Bytes signingPublicKey() const { assert(_object); return _object->_sig_prv_bytes; }
-		inline Bytes hash() const { assert(_object); return _object->_hash; }
+		inline const Bytes &encryptionPrivateKey() const { assert(_object); return _object->_prv_bytes; }
+		inline const Bytes &signingPrivateKey() const { assert(_object); return _object->_sig_prv_bytes; }
+		inline const Bytes &encryptionPublicKey() const { assert(_object); return _object->_prv_bytes; }
+		inline const Bytes &signingPublicKey() const { assert(_object); return _object->_sig_prv_bytes; }
+		inline const Bytes &hash() const { assert(_object); return _object->_hash; }
 		inline std::string hexhash() const { assert(_object); return _object->_hexhash; }
 
 		inline std::string toString() const { assert(_object); return "{Identity:" + _object->_hash.toHex() + "}"; }
diff --git a/src/Interface.cpp b/src/Interface.cpp
index f1e85b7..a0f34b5 100644
--- a/src/Interface.cpp
+++ b/src/Interface.cpp
@@ -1,5 +1,6 @@
 #include "Interface.h"
 
+#include "Identity.h"
 #include "Transport.h"
 
 using namespace RNS;
@@ -20,6 +21,10 @@ using namespace RNS::Type::Interface;
 	_object->_txb += data.size();
 }
 
+const Bytes Interface::get_hash() const {
+	return Identity::full_hash({toString()});
+}
+
 void Interface::process_announce_queue() {
 /*
 	if not hasattr(self, "announce_cap"):
diff --git a/src/Interface.h b/src/Interface.h
index 4355a0f..621f858 100644
--- a/src/Interface.h
+++ b/src/Interface.h
@@ -65,7 +65,7 @@ namespace RNS {
 		}
 
 	public:
-		inline Bytes get_hash() const { /*return Identity::full_hash();*/ return {}; }
+		const Bytes get_hash() const;
 		void process_announce_queue();
 		inline void detach() {}
 
@@ -87,13 +87,13 @@ namespace RNS {
 		inline bool FWD() const { assert(_object); return _object->_FWD; }
 		inline bool RPT() const { assert(_object); return _object->_RPT; }
 		inline std::string name() const { assert(_object); return _object->_name; }
-		inline Bytes ifac_identity() const { assert(_object); return _object->_ifac_identity; }
+		inline const Bytes &ifac_identity() const { assert(_object); return _object->_ifac_identity; }
 		inline Type::Interface::modes mode() const { assert(_object); return _object->_mode; }
 		inline uint32_t bitrate() const { assert(_object); return _object->_bitrate; }
 		inline uint64_t announce_allowed_at() const { assert(_object); return _object->_announce_allowed_at; }
 		inline void announce_allowed_at(uint64_t announce_allowed_at) { assert(_object); _object->_announce_allowed_at = announce_allowed_at; }
 		inline float announce_cap() const { assert(_object); return _object->_announce_cap; }
-		inline std::list<AnnounceEntry> announce_queue() const { assert(_object); return _object->_announce_queue; }
+		inline std::list<AnnounceEntry> &announce_queue() const { assert(_object); return _object->_announce_queue; }
 
 		virtual inline std::string toString() const { assert(_object); return "Interface[" + _object->_name + "]"; }
 
diff --git a/src/Packet.cpp b/src/Packet.cpp
index 9f2d1b8..8b9aeb7 100644
--- a/src/Packet.cpp
+++ b/src/Packet.cpp
@@ -15,10 +15,10 @@ Packet::Packet(const Destination &destination, const Interface &attached_interfa
 
 	if (_object->_destination) {
 		extreme("Creating packet with destination...");
-		// CBA TODO handle NONE
-		if (transport_type == -1) {
-			transport_type = Type::Transport::BROADCAST;
-		}
+		// CBA Should never see empty transport_type
+		//if (transport_type == NONE) {
+		//	transport_type = Type::Transport::BROADCAST;
+		//}
 		// following moved to object constructor to avoid extra NONE object
 		//_destination = destination;
 		_object->_header_type = header_type;
diff --git a/src/Packet.h b/src/Packet.h
index e55b10e..ca87730 100644
--- a/src/Packet.h
+++ b/src/Packet.h
@@ -190,9 +190,9 @@ namespace RNS {
 		inline uint8_t flags() const { assert(_object); return _object->_flags; }
 		inline uint8_t hops() const { assert(_object); return _object->_hops; }
 		inline void hops(uint8_t hops) { assert(_object); _object->_hops = hops; }
-		inline Bytes packet_hash() const { assert(_object); return _object->_packet_hash; }
-		inline Bytes destination_hash() const { assert(_object); return _object->_destination_hash; }
-		inline Bytes transport_id() const { assert(_object); return _object->_transport_id; }
+		inline const Bytes &packet_hash() const { assert(_object); return _object->_packet_hash; }
+		inline const Bytes &destination_hash() const { assert(_object); return _object->_destination_hash; }
+		inline const Bytes &transport_id() const { assert(_object); return _object->_transport_id; }
 		inline void transport_id(const Bytes &transport_id) { assert(_object); _object->_transport_id = transport_id; }
 		inline const Bytes &raw() const { assert(_object); return _object->_raw; }
 		inline const Bytes &data() const { assert(_object); return _object->_data; }
diff --git a/src/Test/TestBytes.cpp b/src/Test/TestBytes.cpp
index 693f552..2f26108 100644
--- a/src/Test/TestBytes.cpp
+++ b/src/Test/TestBytes.cpp
@@ -6,6 +6,21 @@
 #include <map>
 #include <assert.h>
 
+//void testBytesDefault(const RNS::Bytes &bytes = {RNS::Bytes::NONE}) {
+void testBytesDefault(const RNS::Bytes &bytes = {}) {
+	assert(!bytes);
+	assert(bytes.size() == 0);
+	assert(bytes.data() == nullptr);
+}
+
+RNS::Bytes ref("Test");
+const RNS::Bytes &testBytesReference() {
+	// NOTE: Can NOT return local instance as reference!!!
+	//RNS::Bytes ref("Test");
+	RNS::extreme("returning...");
+	return ref;
+}
+
 void testBytes() {
 
 	RNS::Bytes bytes;
@@ -50,14 +65,23 @@ void testBytes() {
 	RNS::extreme("assign prebuf: " + prebuf.toString());
 	RNS::extreme("assign postbuf: " + postbuf.toString());
 
+	// test string assignment
 	bytes = "Foo";
 	assert(bytes.size() == 3);
 	assert(memcmp(bytes.data(), "Foo", bytes.size()) == 0);
 
+	// test string addition
 	bytes = prebuf + postbuf;
 	assert(bytes.size() == 11);
 	assert(memcmp(bytes.data(), "Hello World", bytes.size()) == 0);
 
+	// test string constructor
+	{
+		RNS::Bytes str("Foo");
+		assert(str.size() == 3);
+		assert(memcmp(str.data(), "Foo", str.size()) == 0);
+	}
+
 	// test left in range
 	{
 		RNS::Bytes left(bytes.left(5));
@@ -205,6 +229,20 @@ void testBytes() {
 		assert(bytes.data() == nullptr);
 	}
 
+	// function default argument
+	RNS::head("TestBytes: function default argument", RNS::LOG_EXTREME);
+	testBytesDefault();
+
+	// function reference return
+	RNS::head("TestBytes: function reference return", RNS::LOG_EXTREME);
+	{
+		RNS::Bytes test = testBytesReference();
+		RNS::extreme("returned");
+		assert(test);
+		assert(test.size() == 4);
+		assert(memcmp(test.data(), "Test", test.size()) == 0);
+	}
+
 	// TODO test comparison
 
 }
diff --git a/src/Transport.h b/src/Transport.h
index 4c1b0bf..d7697d3 100644
--- a/src/Transport.h
+++ b/src/Transport.h
@@ -224,6 +224,7 @@ namespace RNS {
 		static void exit_handler();
 
 	private:
+		// CBA MUST use references to interfaces here in order for virtul overrides for send/receive to work
 		//static std::set<std::reference_wrapper<const Interface>, std::less<const Interface>> _interfaces;           // All active interfaces
 		static std::list<std::reference_wrapper<Interface>> _interfaces;           // All active interfaces
 		static std::set<Destination> _destinations;           // All active destinations
diff --git a/src/main.cpp b/src/main.cpp
index 72d60ff..d8bbc71 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -144,6 +144,7 @@ void setup() {
 		//testReference();
 		//testCrypto();
 		RNS::extreme("Finished running tests");
+		//return;
 #endif
 
 		//std::stringstream test;