feat: implement TLS support

codec/encrypt.go

@@ -0,0 +1,51 @@
+package codec
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/hmac"
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/hex"
+	"io"
+)
+
+func EncryptPayload(key []byte, plaintext []byte) ([]byte, []byte, error) {
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, nil, err
+	}
+	aesGCM, err := cipher.NewGCM(block)
+	if err != nil {
+		return nil, nil, err
+	}
+	nonce := make([]byte, aesGCM.NonceSize())
+	if _, err = io.ReadFull(rand.Reader, nonce); err != nil {
+		return nil, nil, err
+	}
+	ciphertext := aesGCM.Seal(nil, nonce, plaintext, nil)
+	return ciphertext, nonce, nil
+}
+
+func DecryptPayload(key []byte, ciphertext []byte, nonce []byte) ([]byte, error) {
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+	aesGCM, err := cipher.NewGCM(block)
+	if err != nil {
+		return nil, err
+	}
+	return aesGCM.Open(nil, nonce, ciphertext, nil)
+}
+
+func CalculateHMAC(key []byte, data []byte) string {
+	h := hmac.New(sha256.New, key)
+	h.Write(data)
+	return hex.EncodeToString(h.Sum(nil))
+}
+
+func VerifyHMAC(key []byte, data []byte, receivedHMAC string) bool {
+	expectedHMAC := CalculateHMAC(key, data)
+	return hmac.Equal([]byte(expectedHMAC), []byte(receivedHMAC))
+}