Adding inner symetric encryption

client/identity.go

@@ -1,9 +1,11 @@
 package client
 
 import (
+	"crypto/rand"
+	"encoding/base64"
 	"encoding/json"
 	"errors"
-	"math/rand"
+	mrand "math/rand"
 	"os"
 	"path/filepath"
 	"strings"
@@ -20,7 +22,7 @@ const maxHiddenCount = 30
 // Package-level random number generator with mutex for thread-safe access
 var (
 	rngMu sync.Mutex
-	rng   = rand.New(rand.NewSource(time.Now().UnixNano()))
+	rng   = mrand.New(mrand.NewSource(time.Now().UnixNano()))
 )
 
 type Identity struct {
@@ -96,6 +98,11 @@ func (id *Identity) InvitePeer(MyName string, ContactName string, MessageServerU
 	}
 	peer.Name = ContactName
 	peer.InvitationId = uuid.New().String() // todo as param to identify then update url
+	symKeyBytes := make([]byte, 32)
+	if _, err = rand.Read(symKeyBytes); err != nil {
+		return nil, err
+	}
+	peer.MySymKey = base64.StdEncoding.EncodeToString(symKeyBytes)
 	/*	if id.MessageServers.Servers == nil {
 			return nil, errors.New("no message servers defined in your identity")
 		}
@@ -161,6 +168,7 @@ func (id *Identity) AnswerInvitation(MyName string, ContactName string, MessageS
 	peer.ContactEncryption = ReceivedContact.EncryptionPublicKey
 	peer.ContactLookupKey = ReceivedContact.LookupPublicKey
 	peer.ContactPublicKey = ReceivedContact.ContactPublicKey
+	peer.MySymKey = ReceivedContact.SymetricKey
 	peer.InvitationId = ReceivedContact.InvitationId
 	peer.InvitationMessage = ReceivedContact.InvitationMessage
 	for srv := range ReceivedContact.PullServers {

client/peer.go

@@ -73,6 +73,7 @@ func (p *Peer) GetMyContact() *meowlib.ContactCard {
 	c.InvitationId = p.InvitationId
 	c.InvitationMessage = p.InvitationMessage
 	c.Name = p.MyName
+	c.SymetricKey = p.MySymKey
 	return &c
 }
 
@@ -199,6 +200,24 @@ func (p *Peer) DeserializeUserMessage(data []byte) (*meowlib.UserMessage, error)
 	return &msg, nil
 }
 
+// SymEncryptPayload applies the shared symmetric key over already-encrypted data.
+// If MySymKey is empty, data is returned unchanged (peer has no symkey configured).
+func (p *Peer) SymEncryptPayload(data []byte) ([]byte, error) {
+	if p.MySymKey == "" {
+		return data, nil
+	}
+	return meowlib.SymEncrypt(p.MySymKey, data)
+}
+
+// SymDecryptPayload removes the outer symmetric encryption layer.
+// If MySymKey is empty, data is returned unchanged.
+func (p *Peer) SymDecryptPayload(data []byte) ([]byte, error) {
+	if p.MySymKey == "" {
+		return data, nil
+	}
+	return meowlib.SymDecrypt(p.MySymKey, data)
+}
+
 // AsymEncryptMessage prepares a message to send to a specific peer contact
 func (p *Peer) AsymEncryptMessage(Message []byte) (*meowlib.EncryptedMessage, error) {
 	var enc *meowlib.EncryptedMessage
@@ -259,19 +278,29 @@ func (p *Peer) ProcessOutboundUserMessage(usermessage *meowlib.UserMessage) (*me
 	if err != nil {
 		return nil, err
 	}
-	// Encrypting it
+	// Asymmetric encryption + signature (inner layer)
 	enc, err := p.AsymEncryptMessage(serializedMessage)
 	if err != nil {
 		return nil, err
 	}
+	// Symmetric encryption (outer layer, if symkey is configured)
+	symEncrypted, err := p.SymEncryptPayload(enc.Data)
+	if err != nil {
+		return nil, err
+	}
 	// Packing it
-	packedMsg := p.PackUserMessage(enc.Data, enc.Signature)
+	packedMsg := p.PackUserMessage(symEncrypted, enc.Signature)
 	return packedMsg, nil
 }
 
 // ProcessInboundUserMessage is a helper function that decrypts and deserializes a user message
 func (p *Peer) ProcessInboundUserMessage(message []byte, signature []byte) (*meowlib.UserMessage, error) {
-	dec, err := p.AsymDecryptMessage(message, signature)
+	// Symmetric decryption (outer layer, if symkey is configured)
+	symDecrypted, err := p.SymDecryptPayload(message)
+	if err != nil {
+		return nil, err
+	}
+	dec, err := p.AsymDecryptMessage(symDecrypted, signature)
 	if err != nil {
 		return nil, err
 	}

client/peerstorage.go

@@ -238,6 +238,9 @@ func (ps *PeerStorage) FinalizeInvitation(ReceivedContact *meowlib.ContactCard)
 			ps.cache[i].ContactEncryption = ReceivedContact.EncryptionPublicKey
 			ps.cache[i].ContactLookupKey = ReceivedContact.LookupPublicKey
 			ps.cache[i].ContactPublicKey = ReceivedContact.ContactPublicKey
+			if ps.cache[i].MySymKey == "" {
+				ps.cache[i].MySymKey = ReceivedContact.SymetricKey
+			}
 			srvs := []string{}
 			for srv := range ReceivedContact.PullServers {
 				srvs = append(srvs, ReceivedContact.PullServers[srv].GetUid())