Rsa Encryption, probably bugged

internal/common/securepacket.go

@@ -0,0 +1,87 @@
+package common
+
+import (
+	"crypto/rand"
+	"encoding/binary"
+	"errors"
+
+	"golang.org/x/crypto/chacha20poly1305"
+)
+
+type SecurePacket struct {
+	Nonce         [24]byte
+	Sid           SessionID
+	DataLength    uint32
+	EncryptedData []byte
+}
+
+func NewSymmetricSecurePacket(key [32]byte, pck *Packet) *SecurePacket {
+	sid := pck.Sid
+	data := pck.ToBytes()
+	aead, err := chacha20poly1305.NewX(key[:])
+	if err != nil {
+		panic(err)
+	}
+
+	nonce := make([]byte, 24)
+	if _, err = rand.Read(nonce); err != nil {
+		panic(err)
+	}
+
+	encrypted := make([]byte, len(data)+aead.Overhead())
+	encrypted = aead.Seal(nil, nonce, data, nil)
+
+	return &SecurePacket{
+		Nonce:         [24]byte(nonce),
+		Sid:           sid,
+		DataLength:    uint32(len(encrypted)),
+		EncryptedData: encrypted,
+	}
+}
+
+func SecurePacketFromBytes(bytes []byte) (*SecurePacket, error) {
+	nonce := bytes[:24]
+	sid := SessionID(bytes[24:32])
+	length := binary.LittleEndian.Uint32(bytes[32:36])
+	if SecureHeaderSize+int(length) > PacketSize {
+		return nil, errors.New("Packet too large")
+	}
+	enc := bytes[36 : SecureHeaderSize+int(length)]
+
+	return &SecurePacket{
+		Nonce:         [24]byte(nonce),
+		Sid:           sid,
+		DataLength:    length,
+		EncryptedData: enc,
+	}, nil
+}
+
+func (secPck *SecurePacket) ToBytes() []byte {
+	encSize := int(secPck.DataLength)
+
+	arr := make([]byte, SecureHeaderSize+encSize)
+	copy(arr[0:24], secPck.Nonce[:])
+	copy(arr[24:32], secPck.Sid[:])
+	binary.LittleEndian.PutUint32(arr[32:36], secPck.DataLength)
+	copy(arr[36:SecureHeaderSize+encSize], secPck.EncryptedData)
+
+	return arr
+}
+
+func (secPck *SecurePacket) ExtractPacket(key [32]byte) (Packet, error) {
+	aead, err := chacha20poly1305.NewX(key[:])
+	if err != nil {
+		panic(err)
+	}
+	data, err := aead.Open(nil, secPck.Nonce[:], secPck.EncryptedData, nil)
+	if err != nil {
+		return Packet{}, err
+	}
+	// fmt.Println(data)
+	packet := PacketFromBytes(
+		data,
+		secPck.DataLength-uint32(HeaderSize)-uint32(aead.Overhead()),
+		secPck.Sid,
+	)
+	return packet, nil
+}