diff --git a/Blockchain.go b/Blockchain.go
index e03d165..a2ea0cc 100644
--- a/Blockchain.go
+++ b/Blockchain.go
@@ -10,6 +10,7 @@ import (
 	"os"
 
 	"github.com/PeernetOfficial/core/blockchain"
+	"github.com/PeernetOfficial/core/protocol"
 )
 
 // UserBlockchain is the user's blockchain and exports functions to directly read and write it
@@ -21,7 +22,7 @@ const filenameUserBlockchain = "self.blockchain"
 // initUserBlockchain initializes the users blockchain. It creates the blockchain file if it does not exist already.
 // If it is corrupted, it will log the error and exit the process.
 func initUserBlockchain() {
-	blockchain.HashFunction = hashData
+	blockchain.HashFunction = protocol.HashData
 	blockchain.PublicKey2NodeID = PublicKey2NodeID
 
 	var err error
diff --git a/Bootstrap.go b/Bootstrap.go
index bd42979..db79321 100644
--- a/Bootstrap.go
+++ b/Bootstrap.go
@@ -20,6 +20,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/PeernetOfficial/core/protocol"
 	"github.com/btcsuite/btcd/btcec"
 )
 
@@ -210,7 +211,7 @@ func contactArbitraryPeer(publicKey *btcec.PublicKey, address *net.UDPAddr, rece
 	if len(packets) == 0 || packets[0].err != nil {
 		return false
 	}
-	raw := &PacketRaw{Command: CommandAnnouncement, Payload: packets[0].raw}
+	raw := &protocol.PacketRaw{Command: protocol.CommandAnnouncement, Payload: packets[0].raw}
 
 	Filters.MessageOutAnnouncement(publicKey, nil, raw, findSelf, nil, nil, nil)
 
diff --git a/Command Traverse.go b/Command Traverse.go
index 727b638..dc31c9f 100644
--- a/Command Traverse.go	
+++ b/Command Traverse.go	
@@ -9,6 +9,8 @@ package core
 import (
 	"math/rand"
 	"time"
+
+	"github.com/PeernetOfficial/core/protocol"
 )
 
 // cmdTraverseForward handles an incoming traverse message that should be forwarded to another peer
@@ -45,7 +47,7 @@ func (peer *PeerInfo) cmdTraverseForward(msg *MessageTraverse) {
 		return
 	}
 
-	peerTarget.send(&PacketRaw{Command: CommandTraverse, Payload: msg.Payload})
+	peerTarget.send(&protocol.PacketRaw{Command: protocol.CommandTraverse, Payload: msg.Payload})
 }
 
 func (peer *PeerInfo) cmdTraverseReceive(msg *MessageTraverse) {
@@ -82,7 +84,7 @@ func (peer *PeerInfo) cmdTraverseReceive(msg *MessageTraverse) {
 
 	// ---- fork packetWorker to decode and validate embedded packet ---
 	// Due to missing connection and other embedded details in the message (such as ports), the packet is not just simply queued to rawPacketsIncoming.
-	decoded, senderPublicKey, err := PacketDecrypt(msg.EmbeddedPacketRaw, peerPublicKey)
+	decoded, senderPublicKey, err := protocol.PacketDecrypt(msg.EmbeddedPacketRaw, peerPublicKey)
 	if err != nil {
 		return
 	}
@@ -92,7 +94,7 @@ func (peer *PeerInfo) cmdTraverseReceive(msg *MessageTraverse) {
 		return
 	} else if decoded.Protocol != 0 {
 		return
-	} else if decoded.Command != CommandAnnouncement {
+	} else if decoded.Command != protocol.CommandAnnouncement {
 		return
 	}
 
@@ -102,7 +104,7 @@ func (peer *PeerInfo) cmdTraverseReceive(msg *MessageTraverse) {
 
 	// process it!
 	switch decoded.Command {
-	case CommandAnnouncement: // Announce
+	case protocol.CommandAnnouncement: // Announce
 		if announce, _ := msgDecodeAnnouncement(raw); announce != nil {
 			if len(announce.UserAgent) > 0 {
 				peerV.UserAgent = announce.UserAgent
diff --git a/Commands.go b/Commands.go
index 54a0566..061937d 100644
--- a/Commands.go
+++ b/Commands.go
@@ -11,6 +11,7 @@ import (
 	"fmt"
 
 	"github.com/PeernetOfficial/core/dht"
+	"github.com/PeernetOfficial/core/protocol"
 )
 
 // respondClosesContactsCount is the number of closest contact to respond.
@@ -198,7 +199,7 @@ func (peer *PeerInfo) cmdPing(msg *MessageRaw) {
 		return
 	}
 
-	raw := &PacketRaw{Command: CommandPong, Sequence: msg.Sequence}
+	raw := &protocol.PacketRaw{Command: protocol.CommandPong, Sequence: msg.Sequence}
 
 	Filters.MessageOutPong(peer, raw)
 
diff --git a/Connection.go b/Connection.go
index 1c451f2..f3bc3a4 100644
--- a/Connection.go
+++ b/Connection.go
@@ -12,6 +12,7 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/PeernetOfficial/core/protocol"
 	"github.com/btcsuite/btcd/btcec"
 )
 
@@ -319,17 +320,17 @@ func (peer *PeerInfo) IsPortForward() (result bool) {
 // ---- sending code ----
 
 // send sends the packet to the peer on the connection
-func (c *Connection) send(packet *PacketRaw, receiverPublicKey *btcec.PublicKey, isFirstPacket bool) (err error) {
+func (c *Connection) send(packet *protocol.PacketRaw, receiverPublicKey *btcec.PublicKey, isFirstPacket bool) (err error) {
 	if c == nil {
 		return errors.New("invalid connection")
 	}
 
 	packet.Protocol = ProtocolVersion
-	packet.setSelfReportedPorts(c.Network)
+	packet.SetSelfReportedPorts(c.Network.SelfReportedPorts())
 
 	Filters.PacketOut(packet, receiverPublicKey, c)
 
-	raw, err := PacketEncrypt(peerPrivateKey, receiverPublicKey, packet)
+	raw, err := protocol.PacketEncrypt(peerPrivateKey, receiverPublicKey, packet)
 	if err != nil {
 		return err
 	}
@@ -339,7 +340,7 @@ func (c *Connection) send(packet *PacketRaw, receiverPublicKey *btcec.PublicKey,
 	err = c.Network.send(c.Address.IP, c.Address.Port, raw)
 
 	// Send Traverse message if the peer is behind a NAT and this is the first message. Only for Announcement.
-	if err == nil && isFirstPacket && c.IsBehindNAT() && c.traversePeer != nil && packet.Command == CommandAnnouncement {
+	if err == nil && isFirstPacket && c.IsBehindNAT() && c.traversePeer != nil && packet.Command == protocol.CommandAnnouncement {
 		c.traversePeer.sendTraverse(packet, receiverPublicKey)
 	}
 
@@ -347,7 +348,7 @@ func (c *Connection) send(packet *PacketRaw, receiverPublicKey *btcec.PublicKey,
 }
 
 // send sends a raw packet to the peer. Only uses active connections.
-func (peer *PeerInfo) send(packet *PacketRaw) (err error) {
+func (peer *PeerInfo) send(packet *protocol.PacketRaw) (err error) {
 	if peer.isVirtual { // special case for peers that were not contacted before
 		for _, address := range peer.targetAddresses {
 			sendAllNetworks(peer.PublicKey, packet, &net.UDPAddr{IP: address.IP, Port: int(address.Port)}, address.PortInternal, peer.traversePeer, nil)
@@ -397,7 +398,7 @@ func (peer *PeerInfo) send(packet *PacketRaw) (err error) {
 }
 
 // sendConnection sends a packet to the peer using the specific connection
-func (peer *PeerInfo) sendConnection(packet *PacketRaw, connection *Connection) (err error) {
+func (peer *PeerInfo) sendConnection(packet *protocol.PacketRaw, connection *Connection) (err error) {
 	isFirstPacketOut := atomic.LoadUint64(&peer.StatsPacketSent) == 0 && atomic.LoadUint64(&peer.StatsPacketReceived) == 0
 	atomic.AddUint64(&peer.StatsPacketSent, 1)
 
@@ -406,7 +407,7 @@ func (peer *PeerInfo) sendConnection(packet *PacketRaw, connection *Connection)
 
 // sendAllNetworks sends a raw packet via all networks. It assigns a new sequence for each sent packet.
 // receiverPortInternal is important for NAT detection and sending the traverse message.
-func sendAllNetworks(receiverPublicKey *btcec.PublicKey, packet *PacketRaw, remote *net.UDPAddr, receiverPortInternal uint16, traversePeer *PeerInfo, sequenceData interface{}) (err error) {
+func sendAllNetworks(receiverPublicKey *btcec.PublicKey, packet *protocol.PacketRaw, remote *net.UDPAddr, receiverPortInternal uint16, traversePeer *PeerInfo, sequenceData interface{}) (err error) {
 	networksMutex.RLock()
 	defer networksMutex.RUnlock()
 
diff --git a/Filter.go b/Filter.go
index e9aec53..90b1659 100644
--- a/Filter.go
+++ b/Filter.go
@@ -12,6 +12,7 @@ import (
 	"log"
 
 	"github.com/PeernetOfficial/core/dht"
+	"github.com/PeernetOfficial/core/protocol"
 	"github.com/btcsuite/btcd/btcec"
 )
 
@@ -37,30 +38,30 @@ var Filters struct {
 
 	// PacketIn is a low-level filter for incoming packets after they are decrypted.
 	// Traverse messages are not covered.
-	PacketIn func(packet *PacketRaw, senderPublicKey *btcec.PublicKey, connection *Connection)
+	PacketIn func(packet *protocol.PacketRaw, senderPublicKey *btcec.PublicKey, connection *Connection)
 
 	// PacketOut is a low-level filter for outgoing packets before they are encrypted.
 	// IPv4 broadcast, IPv6 multicast, and Traverse messages are not covered.
-	PacketOut func(packet *PacketRaw, receiverPublicKey *btcec.PublicKey, connection *Connection)
+	PacketOut func(packet *protocol.PacketRaw, receiverPublicKey *btcec.PublicKey, connection *Connection)
 
 	// MessageIn is a high-level filter for decoded incoming messages. message is of type nil, MessageAnnouncement, MessageResponse, or MessageTraverse
 	MessageIn func(peer *PeerInfo, raw *MessageRaw, message interface{})
 
 	// MessageOutAnnouncement is a high-level filter for outgoing announcements. Peer is nil on first contact.
 	// Broadcast and Multicast messages are not covered.
-	MessageOutAnnouncement func(receiverPublicKey *btcec.PublicKey, peer *PeerInfo, packet *PacketRaw, findSelf bool, findPeer []KeyHash, findValue []KeyHash, files []InfoStore)
+	MessageOutAnnouncement func(receiverPublicKey *btcec.PublicKey, peer *PeerInfo, packet *protocol.PacketRaw, findSelf bool, findPeer []KeyHash, findValue []KeyHash, files []InfoStore)
 
 	// MessageOutResponse is a high-level filter for outgoing responses.
-	MessageOutResponse func(peer *PeerInfo, packet *PacketRaw, hash2Peers []Hash2Peer, filesEmbed []EmbeddedFileData, hashesNotFound [][]byte)
+	MessageOutResponse func(peer *PeerInfo, packet *protocol.PacketRaw, hash2Peers []Hash2Peer, filesEmbed []EmbeddedFileData, hashesNotFound [][]byte)
 
 	// MessageOutTraverse is a high-level filter for outgoing traverse messages.
-	MessageOutTraverse func(peer *PeerInfo, packet *PacketRaw, embeddedPacket *PacketRaw, receiverEnd *btcec.PublicKey)
+	MessageOutTraverse func(peer *PeerInfo, packet *protocol.PacketRaw, embeddedPacket *protocol.PacketRaw, receiverEnd *btcec.PublicKey)
 
 	// MessageOutPing is a high-level filter for outgoing pings.
-	MessageOutPing func(peer *PeerInfo, packet *PacketRaw, connection *Connection)
+	MessageOutPing func(peer *PeerInfo, packet *protocol.PacketRaw, connection *Connection)
 
 	// MessageOutPong is a high-level filter for outgoing pongs.
-	MessageOutPong func(peer *PeerInfo, packet *PacketRaw)
+	MessageOutPong func(peer *PeerInfo, packet *protocol.PacketRaw)
 }
 
 func initFilters() {
@@ -83,30 +84,31 @@ func initFilters() {
 		Filters.IncomingRequest = func(peer *PeerInfo, Action int, Key []byte, Info interface{}) {}
 	}
 	if Filters.PacketIn == nil {
-		Filters.PacketIn = func(packet *PacketRaw, senderPublicKey *btcec.PublicKey, c *Connection) {}
+		Filters.PacketIn = func(packet *protocol.PacketRaw, senderPublicKey *btcec.PublicKey, c *Connection) {}
 	}
 	if Filters.PacketOut == nil {
-		Filters.PacketOut = func(packet *PacketRaw, receiverPublicKey *btcec.PublicKey, c *Connection) {}
+		Filters.PacketOut = func(packet *protocol.PacketRaw, receiverPublicKey *btcec.PublicKey, c *Connection) {}
 	}
 	if Filters.MessageIn == nil {
 		Filters.MessageIn = func(peer *PeerInfo, raw *MessageRaw, message interface{}) {}
 	}
 	if Filters.MessageOutAnnouncement == nil {
-		Filters.MessageOutAnnouncement = func(receiverPublicKey *btcec.PublicKey, peer *PeerInfo, packet *PacketRaw, findSelf bool, findPeer []KeyHash, findValue []KeyHash, files []InfoStore) {
+		Filters.MessageOutAnnouncement = func(receiverPublicKey *btcec.PublicKey, peer *PeerInfo, packet *protocol.PacketRaw, findSelf bool, findPeer []KeyHash, findValue []KeyHash, files []InfoStore) {
 		}
 	}
 	if Filters.MessageOutResponse == nil {
-		Filters.MessageOutResponse = func(peer *PeerInfo, packet *PacketRaw, hash2Peers []Hash2Peer, filesEmbed []EmbeddedFileData, hashesNotFound [][]byte) {
+		Filters.MessageOutResponse = func(peer *PeerInfo, packet *protocol.PacketRaw, hash2Peers []Hash2Peer, filesEmbed []EmbeddedFileData, hashesNotFound [][]byte) {
 		}
 	}
 	if Filters.MessageOutTraverse == nil {
-		Filters.MessageOutTraverse = func(peer *PeerInfo, packet *PacketRaw, embeddedPacket *PacketRaw, receiverEnd *btcec.PublicKey) {}
+		Filters.MessageOutTraverse = func(peer *PeerInfo, packet *protocol.PacketRaw, embeddedPacket *protocol.PacketRaw, receiverEnd *btcec.PublicKey) {
+		}
 	}
 	if Filters.MessageOutPing == nil {
-		Filters.MessageOutPing = func(peer *PeerInfo, packet *PacketRaw, connection *Connection) {}
+		Filters.MessageOutPing = func(peer *PeerInfo, packet *protocol.PacketRaw, connection *Connection) {}
 	}
 	if Filters.MessageOutPong == nil {
-		Filters.MessageOutPong = func(peer *PeerInfo, packet *PacketRaw) {}
+		Filters.MessageOutPong = func(peer *PeerInfo, packet *protocol.PacketRaw) {}
 	}
 }
 
diff --git a/Kademlia.go b/Kademlia.go
index a987ea2..e50638b 100644
--- a/Kademlia.go
+++ b/Kademlia.go
@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"github.com/PeernetOfficial/core/dht"
+	"github.com/PeernetOfficial/core/protocol"
 )
 
 const alpha = 5       // Count of nodes to be contacted in parallel for finding a key
@@ -127,7 +128,7 @@ func (peer *PeerInfo) sendAnnouncementStore(fileHash []byte, fileSize uint64) {
 
 // Data2Hash returns the hash for the data
 func Data2Hash(data []byte) (hash []byte) {
-	return hashData(data)
+	return protocol.HashData(data)
 }
 
 // GetData returns the requested data. It checks first the local store and then tries via DHT.
@@ -152,14 +153,14 @@ func GetDataDHT(hash []byte) (data []byte, senderNodeID []byte, found bool) {
 
 // StoreDataLocal stores data into the local warehouse.
 func StoreDataLocal(data []byte) error {
-	key := hashData(data)
+	key := protocol.HashData(data)
 	return Warehouse.Set(key, data)
 }
 
 // StoreDataDHT stores data locally and informs closestCount peers in the DHT about it.
 // Remote peers may choose to keep a record (in case another peers asks) or mirror the full data.
 func StoreDataDHT(data []byte, closestCount int) error {
-	key := hashData(data)
+	key := protocol.HashData(data)
 	if err := Warehouse.Set(key, data); err != nil {
 		return err
 	}
diff --git a/Message Encoding.go b/Message Encoding.go
index b6aa6da..db727c8 100644
--- a/Message Encoding.go	
+++ b/Message Encoding.go	
@@ -16,6 +16,7 @@ import (
 	"time"
 	"unicode/utf8"
 
+	"github.com/PeernetOfficial/core/protocol"
 	"github.com/btcsuite/btcd/btcec"
 )
 
@@ -25,25 +26,6 @@ const ProtocolVersion = 0
 // UserAgent should be set by the caller
 var UserAgent = "Peernet Core/0.1"
 
-// Commands between peers
-const (
-	// Peer List Management
-	CommandAnnouncement   = 0 // Announcement
-	CommandResponse       = 1 // Response
-	CommandPing           = 2 // Keep-alive message (no payload).
-	CommandPong           = 3 // Response to ping (no payload).
-	CommandLocalDiscovery = 4 // Local discovery
-	CommandTraverse       = 5 // Help establish a connection between 2 remote peers
-
-	// Blockchain
-	CommandGet = 6 // Request blocks for specified peer.
-
-	// File Discovery
-
-	// Debug
-	CommandChat = 10 // Chat message [debug]
-)
-
 // Actions between peers, sent via Announcement message. They correspond to the bit array index.
 const (
 	ActionFindSelf  = 0 // FIND_SELF Request closest neighbors to self
@@ -65,7 +47,7 @@ const (
 
 // MessageRaw is a high-level message between peers that has not been decoded
 type MessageRaw struct {
-	PacketRaw
+	protocol.PacketRaw
 	SenderPublicKey *btcec.PublicKey // Sender Public Key, ECDSA (secp256k1) 257-bit
 	connection      *Connection      // Connection that received the packet
 	sequence        *sequenceExpiry  // Sequence
@@ -478,7 +460,7 @@ func decodeEmbeddedFile(data []byte, count int) (filesEmbed []EmbeddedFileData,
 		index += sizeField
 
 		// validate the hash
-		if !bytes.Equal(hash, hashData(fileData)) {
+		if !bytes.Equal(hash, protocol.HashData(fileData)) {
 			return nil, read, false
 		}
 
@@ -494,7 +476,7 @@ const udpMaxPacketSize = 65507
 
 // isPacketSizeExceed checks if the max packet size would be exceeded with the payload
 func isPacketSizeExceed(currentSize int, testSize int) bool {
-	return currentSize+testSize > udpMaxPacketSize-packetLengthMin
+	return currentSize+testSize > udpMaxPacketSize-protocol.PacketLengthMin
 }
 
 func FeatureSupport() (feature byte) {
@@ -656,7 +638,7 @@ createPacketLoop:
 }
 
 // EmbeddedFileSizeMax is the maximum size of embedded files in response messages. Any file exceeding that must be shared via regular file transfer.
-const EmbeddedFileSizeMax = udpMaxPacketSize - packetLengthMin - announcementPayloadHeaderSize - 2 - 35
+const EmbeddedFileSizeMax = udpMaxPacketSize - protocol.PacketLengthMin - announcementPayloadHeaderSize - 2 - 35
 
 // msgEncodeResponse encodes a response message
 // hash2Peers will be modified.
@@ -826,19 +808,6 @@ func encodePeerRecord(raw []byte, peer *PeerRecord, reason uint8) {
 	binary.LittleEndian.PutUint16(raw[63:63+2], peer.IPv6PortReportedExternal)
 }
 
-// setSelfReportedPorts sets the fields Internal Port and External Port according to the connection details.
-// This is important for the remote peer to make smart decisions whether this peer is behind a NAT/firewall and supports port forwarding/UPnP.
-func (packet *PacketRaw) setSelfReportedPorts(n *Network) {
-	if packet.Command != CommandAnnouncement && packet.Command != CommandResponse { // only for Announcement and Response messages
-		return
-	}
-
-	portI, portE := n.SelfReportedPorts()
-
-	binary.LittleEndian.PutUint16(packet.Payload[15:17], portI)
-	binary.LittleEndian.PutUint16(packet.Payload[17:19], portE)
-}
-
 // ---- Traverse ----
 
 const traversePayloadHeaderSize = 76 + 65 + 28
@@ -882,7 +851,7 @@ func msgDecodeTraverse(msg *MessageRaw) (result *MessageTraverse, err error) {
 
 	signature := msg.Payload[76+sizePacketEmbed : 76+sizePacketEmbed+65]
 
-	result.SignerPublicKey, _, err = btcec.RecoverCompact(btcec.S256(), signature, hashData(msg.Payload[:76+sizePacketEmbed]))
+	result.SignerPublicKey, _, err = btcec.RecoverCompact(btcec.S256(), signature, protocol.HashData(msg.Payload[:76+sizePacketEmbed]))
 	if err != nil {
 		return nil, err
 	}
@@ -932,7 +901,7 @@ func msgEncodeTraverse(senderPrivateKey *btcec.PrivateKey, embeddedPacketRaw []b
 	copy(raw[76:76+sizePacketEmbed], embeddedPacketRaw)
 
 	// add signature
-	signature, err := btcec.SignCompact(btcec.S256(), senderPrivateKey, hashData(raw[:76+sizePacketEmbed]), true)
+	signature, err := btcec.SignCompact(btcec.S256(), senderPrivateKey, protocol.HashData(raw[:76+sizePacketEmbed]), true)
 	if err != nil {
 		return nil, err
 	}
@@ -978,7 +947,7 @@ func msgEncodeTraverseSetAddress(raw []byte, connectionIPv4, connectionIPv6 *Con
 
 // pingConnection sends a ping to the target peer via the specified connection
 func (peer *PeerInfo) pingConnection(connection *Connection) {
-	raw := &PacketRaw{Command: CommandPing, Sequence: peer.msgNewSequence(nil).sequence}
+	raw := &protocol.PacketRaw{Command: protocol.CommandPing, Sequence: peer.msgNewSequence(nil).sequence}
 	Filters.MessageOutPing(peer, raw, connection)
 
 	err := peer.sendConnection(raw, connection)
@@ -991,7 +960,7 @@ func (peer *PeerInfo) pingConnection(connection *Connection) {
 
 // Chat sends a text message
 func (peer *PeerInfo) Chat(text string) {
-	peer.send(&PacketRaw{Command: CommandChat, Payload: []byte(text)})
+	peer.send(&protocol.PacketRaw{Command: protocol.CommandChat, Payload: []byte(text)})
 }
 
 // sendAnnouncement sends the announcement message. It acquires a new sequence for each message.
@@ -1000,7 +969,7 @@ func (peer *PeerInfo) sendAnnouncement(sendUA, findSelf bool, findPeer []KeyHash
 
 	for _, packet := range packets {
 		packet.sequence = peer.msgNewSequence(sequenceData)
-		raw := &PacketRaw{Command: CommandAnnouncement, Payload: packet.raw, Sequence: packet.sequence.sequence}
+		raw := &protocol.PacketRaw{Command: protocol.CommandAnnouncement, Payload: packet.raw, Sequence: packet.sequence.sequence}
 		Filters.MessageOutAnnouncement(peer.PublicKey, peer, raw, findSelf, findPeer, findValue, files)
 		packet.err = peer.send(raw)
 	}
@@ -1013,7 +982,7 @@ func (peer *PeerInfo) sendResponse(sequence uint32, sendUA bool, hash2Peers []Ha
 	packets, err := msgEncodeResponse(sendUA, hash2Peers, filesEmbed, hashesNotFound)
 
 	for _, packet := range packets {
-		raw := &PacketRaw{Command: CommandResponse, Payload: packet, Sequence: sequence}
+		raw := &protocol.PacketRaw{Command: protocol.CommandResponse, Payload: packet, Sequence: sequence}
 		Filters.MessageOutResponse(peer, raw, hash2Peers, filesEmbed, hashesNotFound)
 		peer.send(raw)
 	}
@@ -1022,12 +991,12 @@ func (peer *PeerInfo) sendResponse(sequence uint32, sendUA bool, hash2Peers []Ha
 }
 
 // sendTraverse sends a traverse message
-func (peer *PeerInfo) sendTraverse(packet *PacketRaw, receiverEnd *btcec.PublicKey) (err error) {
+func (peer *PeerInfo) sendTraverse(packet *protocol.PacketRaw, receiverEnd *btcec.PublicKey) (err error) {
 	packet.Protocol = ProtocolVersion
 	// self-reported ports are not set, as this isn't sent via a specific network but a relay
-	//packet.setSelfReportedPorts(c.Network)
+	//packet.SetSelfReportedPorts(c.Network.SelfReportedPorts())
 
-	embeddedPacketRaw, err := PacketEncrypt(peerPrivateKey, receiverEnd, packet)
+	embeddedPacketRaw, err := protocol.PacketEncrypt(peerPrivateKey, receiverEnd, packet)
 	if err != nil {
 		return err
 	}
@@ -1037,7 +1006,7 @@ func (peer *PeerInfo) sendTraverse(packet *PacketRaw, receiverEnd *btcec.PublicK
 		return err
 	}
 
-	raw := &PacketRaw{Command: CommandTraverse, Payload: packetRaw}
+	raw := &protocol.PacketRaw{Command: protocol.CommandTraverse, Payload: packetRaw}
 
 	Filters.MessageOutTraverse(peer, raw, packet, receiverEnd)
 
diff --git a/Message Sequence.go b/Message Sequence.go
index d48c7f1..c33532e 100644
--- a/Message Sequence.go	
+++ b/Message Sequence.go	
@@ -21,6 +21,7 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/PeernetOfficial/core/protocol"
 	"github.com/btcsuite/btcd/btcec"
 )
 
@@ -97,7 +98,7 @@ func msgArbitrarySequence(publicKey *btcec.PublicKey, data interface{}) (info *s
 // msgValidateSequence validates the sequence number of an incoming message. It will set raw.sequence if valid.
 func msgValidateSequence(raw *MessageRaw, invalidate bool) (valid bool, rtt time.Duration) {
 	// Only Response and Pong
-	if raw.Command != CommandResponse && raw.Command != CommandPong {
+	if raw.Command != protocol.CommandResponse && raw.Command != protocol.CommandPong {
 		return true, rtt
 	}
 
@@ -123,7 +124,7 @@ func msgValidateSequence(raw *MessageRaw, invalidate bool) (valid bool, rtt time
 	// invalidate the sequence immediately?
 	if invalidate {
 		delete(sequences, key)
-	} else if raw.Command == CommandResponse {
+	} else if raw.Command == protocol.CommandResponse {
 		// Special case CommandResponse: Extend validity in case there are follow-up responses by half of the round-trip time since they will be sent one-way.
 		sequence.expires = time.Now().Add(time.Duration(ReplyTimeout) * time.Second / 2)
 	}
@@ -136,7 +137,7 @@ func msgValidateSequence(raw *MessageRaw, invalidate bool) (valid bool, rtt time
 // msgInvalidateSequence invalidates the sequence number.
 func msgInvalidateSequence(raw *MessageRaw) {
 	// Only Response
-	if raw.Command != CommandResponse {
+	if raw.Command != protocol.CommandResponse {
 		return
 	}
 
diff --git a/Network IPv4 Broadcast.go b/Network IPv4 Broadcast.go
index 1f3c773..4f5787f 100644
--- a/Network IPv4 Broadcast.go	
+++ b/Network IPv4 Broadcast.go	
@@ -14,6 +14,7 @@ import (
 	"strconv"
 	"time"
 
+	"github.com/PeernetOfficial/core/protocol"
 	"github.com/PeernetOfficial/core/reuseport"
 	"github.com/btcsuite/btcd/btcec"
 )
@@ -77,7 +78,7 @@ func (network *Network) BroadcastIPv4Listen() {
 
 		//fmt.Printf("BroadcastIPv4Listen from %s at network %s\n", sender.String(), network.address.String())
 
-		if length < packetLengthMin {
+		if length < protocol.PacketLengthMin {
 			// Discard packets that do not meet the minimum length.
 			continue
 		}
@@ -94,7 +95,7 @@ func (network *Network) BroadcastIPv4Send() (err error) {
 		return packets[0].err
 	}
 
-	raw, err := PacketEncrypt(peerPrivateKey, ipv4BroadcastPublicKey, &PacketRaw{Protocol: ProtocolVersion, Command: CommandLocalDiscovery, Payload: packets[0].raw})
+	raw, err := protocol.PacketEncrypt(peerPrivateKey, ipv4BroadcastPublicKey, &protocol.PacketRaw{Protocol: ProtocolVersion, Command: protocol.CommandLocalDiscovery, Payload: packets[0].raw})
 	if err != nil {
 		return err
 	}
diff --git a/Network IPv6 Multicast.go b/Network IPv6 Multicast.go
index 75d8b93..beba9d3 100644
--- a/Network IPv6 Multicast.go	
+++ b/Network IPv6 Multicast.go	
@@ -22,6 +22,7 @@ import (
 	"strconv"
 	"time"
 
+	"github.com/PeernetOfficial/core/protocol"
 	"github.com/PeernetOfficial/core/reuseport"
 	"github.com/btcsuite/btcd/btcec"
 	"golang.org/x/net/ipv6"
@@ -123,7 +124,7 @@ func (network *Network) MulticastIPv6Listen() {
 
 		//fmt.Printf("MulticastIPv6Listen from %s at network %s\n", sender.String(), network.address.String())
 
-		if length < packetLengthMin {
+		if length < protocol.PacketLengthMin {
 			// Discard packets that do not meet the minimum length.
 			continue
 		}
@@ -140,7 +141,7 @@ func (network *Network) MulticastIPv6Send() (err error) {
 		return packets[0].err
 	}
 
-	raw, err := PacketEncrypt(peerPrivateKey, ipv6MulticastPublicKey, &PacketRaw{Protocol: ProtocolVersion, Command: CommandLocalDiscovery, Payload: packets[0].raw})
+	raw, err := protocol.PacketEncrypt(peerPrivateKey, ipv6MulticastPublicKey, &protocol.PacketRaw{Protocol: ProtocolVersion, Command: protocol.CommandLocalDiscovery, Payload: packets[0].raw})
 	if err != nil {
 		return err
 	}
diff --git a/Network.go b/Network.go
index 54347d9..4056ce9 100644
--- a/Network.go
+++ b/Network.go
@@ -13,6 +13,7 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/PeernetOfficial/core/protocol"
 	"github.com/PeernetOfficial/core/upnp"
 )
 
@@ -131,7 +132,7 @@ func (network *Network) Listen() {
 			continue
 		}
 
-		if length < packetLengthMin {
+		if length < protocol.PacketLengthMin {
 			// Discard packets that do not meet the minimum length.
 			continue
 		}
@@ -144,7 +145,7 @@ func (network *Network) Listen() {
 // packetWorker handles incoming packets.
 func packetWorker(packets <-chan networkWire) {
 	for packet := range packets {
-		decoded, senderPublicKey, err := PacketDecrypt(packet.raw, packet.receiverPublicKey)
+		decoded, senderPublicKey, err := protocol.PacketDecrypt(packet.raw, packet.receiverPublicKey)
 		if err != nil {
 			//Filters.LogError("packetWorker", "decrypting packet from '%s': %s\n", packet.sender.String(), err.Error())  // Only log for debug purposes.
 			continue
@@ -177,7 +178,7 @@ func packetWorker(packets <-chan networkWire) {
 		raw := &MessageRaw{SenderPublicKey: senderPublicKey, PacketRaw: *decoded, connection: connection}
 
 		switch decoded.Command {
-		case CommandAnnouncement: // Announce
+		case protocol.CommandAnnouncement: // Announce
 			if announce, _ := msgDecodeAnnouncement(raw); announce != nil {
 				// Update known internal/external port and User Agent
 				connection.PortInternal = announce.PortInternal
@@ -194,7 +195,7 @@ func packetWorker(packets <-chan networkWire) {
 				peer.cmdAnouncement(announce)
 			}
 
-		case CommandResponse: // Response
+		case protocol.CommandResponse: // Response
 			if response, _ := msgDecodeResponse(raw); response != nil {
 				// Validate sequence number which prevents unsolicited responses.
 				if valid, rtt := msgValidateSequence(raw, response.Actions&(1<<ActionSequenceLast) > 0); !valid {
@@ -219,7 +220,7 @@ func packetWorker(packets <-chan networkWire) {
 				peer.cmdResponse(response)
 			}
 
-		case CommandLocalDiscovery: // Local discovery, sent via IPv4 broadcast and IPv6 multicast
+		case protocol.CommandLocalDiscovery: // Local discovery, sent via IPv4 broadcast and IPv6 multicast
 			if announce, _ := msgDecodeAnnouncement(raw); announce != nil {
 				if len(announce.UserAgent) > 0 {
 					peer.UserAgent = announce.UserAgent
@@ -233,11 +234,11 @@ func packetWorker(packets <-chan networkWire) {
 				peer.cmdLocalDiscovery(announce)
 			}
 
-		case CommandPing: // Ping
+		case protocol.CommandPing: // Ping
 			Filters.MessageIn(peer, raw, nil)
 			peer.cmdPing(raw)
 
-		case CommandPong: // Ping
+		case protocol.CommandPong: // Ping
 			// Validate sequence number which prevents unsolicited responses.
 			if valid, rtt := msgValidateSequence(raw, true); !valid {
 				//Filters.LogError("packetWorker", "message with invalid sequence %d command %d from %s\n", raw.Sequence, raw.Command, raw.connection.Address.String()) // Only log for debug purposes.
@@ -250,11 +251,11 @@ func packetWorker(packets <-chan networkWire) {
 
 			peer.cmdPong(raw)
 
-		case CommandChat: // Chat [debug]
+		case protocol.CommandChat: // Chat [debug]
 			Filters.MessageIn(peer, raw, nil)
 			peer.cmdChat(raw)
 
-		case CommandTraverse:
+		case protocol.CommandTraverse:
 			if traverse, _ := msgDecodeTraverse(raw); traverse != nil {
 				Filters.MessageIn(peer, raw, traverse)
 				if traverse.TargetPeer.IsEqual(peerPublicKey) && traverse.AuthorizedRelayPeer.IsEqual(peer.PublicKey) {
diff --git a/Peer ID.go b/Peer ID.go
index 6a0eabb..7333fb7 100644
--- a/Peer ID.go	
+++ b/Peer ID.go	
@@ -14,6 +14,7 @@ import (
 	"sync"
 
 	"github.com/PeernetOfficial/core/dht"
+	"github.com/PeernetOfficial/core/protocol"
 	"github.com/btcsuite/btcd/btcec"
 )
 
@@ -198,7 +199,7 @@ func publicKey2Compressed(publicKey *btcec.PublicKey) [btcec.PubKeyBytesLenCompr
 
 // PublicKey2NodeID translates the Public Key into the node ID used in the Kademlia network.
 func PublicKey2NodeID(publicKey *btcec.PublicKey) (nodeID []byte) {
-	return hashData(publicKey.SerializeCompressed())
+	return protocol.HashData(publicKey.SerializeCompressed())
 }
 
 // records2Nodes translates infoPeer structures to nodes. If the reported nodes are not in the peer table, it will create temporary PeerInfo structures.
diff --git a/Test_test.go b/Test_test.go
index 37730ef..63c36f0 100644
--- a/Test_test.go
+++ b/Test_test.go
@@ -4,6 +4,8 @@ package core
 import (
 	"fmt"
 	"testing"
+
+	"github.com/PeernetOfficial/core/protocol"
 )
 
 func TestMessageEncodingAnnouncement(t *testing.T) {
@@ -14,14 +16,14 @@ func TestMessageEncodingAnnouncement(t *testing.T) {
 	}
 
 	// encode and decode announcement
-	packetR := PacketRaw{Protocol: 0, Command: CommandAnnouncement, Sequence: 123}
+	packetR := protocol.PacketRaw{Protocol: 0, Command: protocol.CommandAnnouncement, Sequence: 123}
 
 	var findPeer []KeyHash
 	var findValue []KeyHash
 	var files []InfoStore
 
-	hash1 := hashData([]byte("test"))
-	hash2 := hashData([]byte("test3"))
+	hash1 := protocol.HashData([]byte("test"))
+	hash2 := protocol.HashData([]byte("test3"))
 	findPeer = append(findPeer, KeyHash{Hash: hash1})
 	findValue = append(findValue, KeyHash{Hash: hash2})
 
@@ -47,7 +49,7 @@ func TestMessageEncodingResponse(t *testing.T) {
 	}
 
 	// encode and decode response
-	packetR := PacketRaw{Protocol: 0, Command: CommandResponse}
+	packetR := protocol.PacketRaw{Protocol: 0, Command: protocol.CommandResponse}
 
 	var hash2Peers []Hash2Peer
 	var filesEmbed []EmbeddedFileData
@@ -55,12 +57,12 @@ func TestMessageEncodingResponse(t *testing.T) {
 
 	file1Data := []byte("test")
 	file2Data := []byte("test3")
-	file1 := EmbeddedFileData{ID: KeyHash{hashData(file1Data)}, Data: file1Data}
-	file2 := EmbeddedFileData{ID: KeyHash{hashData(file2Data)}, Data: file2Data}
+	file1 := EmbeddedFileData{ID: KeyHash{protocol.HashData(file1Data)}, Data: file1Data}
+	file2 := EmbeddedFileData{ID: KeyHash{protocol.HashData(file2Data)}, Data: file2Data}
 	filesEmbed = append(filesEmbed, file1)
 	filesEmbed = append(filesEmbed, file2)
 
-	hashesNotFound = append(hashesNotFound, hashData([]byte("NA")))
+	hashesNotFound = append(hashesNotFound, protocol.HashData([]byte("NA")))
 
 	packetsRaw, err := msgEncodeResponse(true, hash2Peers, filesEmbed, hashesNotFound)
 	if err != nil {
diff --git a/protocol/Command.go b/protocol/Command.go
new file mode 100644
index 0000000..91b3234
--- /dev/null
+++ b/protocol/Command.go
@@ -0,0 +1,27 @@
+/*
+File Name:  Command.go
+Copyright:  2021 Peernet s.r.o.
+Author:     Peter Kleissner
+*/
+
+package protocol
+
+// Commands between peers
+const (
+	// Peer List Management
+	CommandAnnouncement   = 0 // Announcement
+	CommandResponse       = 1 // Response
+	CommandPing           = 2 // Keep-alive message (no payload).
+	CommandPong           = 3 // Response to ping (no payload).
+	CommandLocalDiscovery = 4 // Local discovery
+	CommandTraverse       = 5 // Help establish a connection between 2 remote peers
+
+	// Blockchain
+	CommandGetBlock = 6 // Request blocks for specified peer.
+
+	// File Discovery
+	CommandTransfer = 8 // File transfer.
+
+	// Debug
+	CommandChat = 10 // Chat message [debug]
+)
diff --git a/protocol/Hash.go b/protocol/Hash.go
new file mode 100644
index 0000000..83eb9dc
--- /dev/null
+++ b/protocol/Hash.go
@@ -0,0 +1,18 @@
+/*
+File Name:  Hash.go
+Copyright:  2021 Peernet s.r.o.
+Author:     Peter Kleissner
+*/
+
+package protocol
+
+import "lukechampine.com/blake3"
+
+// HashData abstracts the hash function.
+func HashData(data []byte) (hash []byte) {
+	hash32 := blake3.Sum256(data)
+	return hash32[:]
+}
+
+// HashSize is blake3 hash digest size = 256 bits
+const HashSize = 32
diff --git a/Packet Encoding.go b/protocol/Packet Encoding.go
similarity index 83%
rename from Packet Encoding.go
rename to protocol/Packet Encoding.go
index 9e3b3bb..3044cfc 100644
--- a/Packet Encoding.go	
+++ b/protocol/Packet Encoding.go	
@@ -19,7 +19,7 @@ The signature is applied on the entire packet, which guarantees that the signatu
 Because the signature could be a possible fingerpint, it is encrypted itself.
 */
 
-package core
+package protocol
 
 import (
 	"encoding/binary"
@@ -28,7 +28,6 @@ import (
 
 	"github.com/btcsuite/btcd/btcec"
 	"golang.org/x/crypto/salsa20"
-	"lukechampine.com/blake3"
 )
 
 // PacketRaw is a decrypted P2P message
@@ -40,7 +39,7 @@ type PacketRaw struct {
 }
 
 // The minimum packet size is 12 bytes (minimum header size) + 65 bytes (signature)
-const packetLengthMin = 12 + signatureSize
+const PacketLengthMin = 12 + signatureSize
 const signatureSize = 65
 const maxRandomGarbage = 20
 
@@ -60,7 +59,7 @@ func PacketDecrypt(raw []byte, receiverPublicKey *btcec.PublicKey) (packet *Pack
 	keySalsa := publicKeyToSalsa20Key(receiverPublicKey)
 	salsa20.XORKeyStream(signature[:], signature[:], nonce, keySalsa)
 
-	senderPublicKey, _, err = btcec.RecoverCompact(btcec.S256(), signature[:], hashData(raw[:len(raw)-signatureSize]))
+	senderPublicKey, _, err = btcec.RecoverCompact(btcec.S256(), signature[:], HashData(raw[:len(raw)-signatureSize]))
 	if err != nil {
 		return nil, nil, err
 	}
@@ -87,8 +86,8 @@ func PacketDecrypt(raw []byte, receiverPublicKey *btcec.PublicKey) (packet *Pack
 
 // PacketEncrypt encrypts a packet using the provided senders private key and receivers compressed public key.
 func PacketEncrypt(senderPrivateKey *btcec.PrivateKey, receiverPublicKey *btcec.PublicKey, packet *PacketRaw) (raw []byte, err error) {
-	garbage := packetGarbage(packetLengthMin + len(packet.Payload))
-	raw = make([]byte, packetLengthMin+len(packet.Payload)+len(garbage))
+	garbage := packetGarbage(PacketLengthMin + len(packet.Payload))
+	raw = make([]byte, PacketLengthMin+len(packet.Payload)+len(garbage))
 
 	nonceC := rand.Uint32()
 	nonce := make([]byte, 8)
@@ -109,7 +108,7 @@ func PacketEncrypt(senderPrivateKey *btcec.PrivateKey, receiverPublicKey *btcec.
 	salsa20.XORKeyStream(raw[4:12+len(packet.Payload)+len(garbage)], raw[4:12+len(packet.Payload)+len(garbage)], nonce, keySalsa)
 
 	// add signature
-	signature, err := btcec.SignCompact(btcec.S256(), senderPrivateKey, hashData(raw[:len(raw)-signatureSize]), true)
+	signature, err := btcec.SignCompact(btcec.S256(), senderPrivateKey, HashData(raw[:len(raw)-signatureSize]), true)
 	if err != nil {
 		return nil, err
 	}
@@ -146,11 +145,13 @@ func publicKeyToSalsa20Key(publicKey *btcec.PublicKey) (key *[32]byte) {
 	return key
 }
 
-// hashData abstracts the hash function.
-func hashData(data []byte) (hash []byte) {
-	hash32 := blake3.Sum256(data)
-	return hash32[:]
-}
+// SetSelfReportedPorts sets the fields Internal Port and External Port according to the connection details.
+// This is important for the remote peer to make smart decisions whether this peer is behind a NAT/firewall and supports port forwarding/UPnP.
+func (packet *PacketRaw) SetSelfReportedPorts(portI, portE uint16) {
+	if packet.Command != CommandAnnouncement && packet.Command != CommandResponse { // only for Announcement and Response messages
+		return
+	}
 
-// HashSize is blake3 hash digest size = 256 bits
-const HashSize = 32
+	binary.LittleEndian.PutUint16(packet.Payload[15:17], portI)
+	binary.LittleEndian.PutUint16(packet.Payload[17:19], portE)
+}
diff --git a/protocol/readme.md b/protocol/readme.md
new file mode 100644
index 0000000..cf3707d
--- /dev/null
+++ b/protocol/readme.md
@@ -0,0 +1,3 @@
+# Protocol
+
+The Peernet Protocol is defined in the Whitepaper and implemented here accordingly.