Server and Client daemons functional

crypto.go

@@ -12,55 +12,6 @@ import (
 	"golang.org/x/crypto/chacha20poly1305"
 )
 
-//var cert *x509.Certificate
-//var key *rsa.PrivateKey
-//
-//func encryptBytes(data []byte) []byte {
-//	if cert == nil || key == nil {
-//		loadCerts()
-//	}
-//
-//	encrypted, err := rsa.EncryptPKCS1v15(rand.Reader, cert.PublicKey.(*rsa.PublicKey), data)
-//	if err != nil {
-//		fmt.Println("Error encrypting data,", err)
-//		os.Exit(1)
-//	}
-//	return encrypted
-//}
-//
-//func decryptBytes(data []byte) []byte {
-//	if cert == nil || key == nil {
-//		loadCerts()
-//	}
-//
-//	decrypted, err := rsa.DecryptPKCS1v15(rand.Reader, key, data)
-//	if err != nil {
-//		fmt.Println("Error decrypting data,", err)
-//		os.Exit(1)
-//	}
-//	return decrypted
-//}
-//
-//func loadCerts() {
-//	var err error
-//	certBytes, err := os.ReadFile(config.GetAsString("Crypto.cert_path"))
-//	keyBytes, err := os.ReadFile(config.GetAsString("Crypto.key_path"))
-//	if err != nil {
-//		fmt.Println("Error reading cert or key,", err)
-//		os.Exit(1)
-//	}
-//
-//	cert, err = x509.ParseCertificate(certBytes)
-//	if err != nil {
-//		fmt.Println("Error parsing certificate,", err)
-//		os.Exit(1)
-//	}
-//	key, err = x509.ParsePKCS1PrivateKey(keyBytes)
-//	if err != nil {
-//		fmt.Println("Error parsing private key,", err)
-//	}
-//}
-
 // GenerateKey returns a base64-encoded 32-byte random key suitable to use as the
 // symmetric passphrase for age scrypt mode. Store this securely (never in Git).
 func GenerateKey() (string, error) {
@@ -150,3 +101,32 @@ func DecryptFileXChaCha(keyB64, inPath, outPath string, aad []byte) error {
 	}
 	return nil
 }
+
+func DecryptFileFromBytes(keyB64 string, inBytes []byte, outPath string, aad []byte) error {
+	key, err := decodeKey(keyB64)
+	if err != nil {
+		return err
+	}
+
+	aead, err := chacha20poly1305.NewX(key)
+	if err != nil {
+		return fmt.Errorf("new aead: %w", err)
+	}
+
+	if len(inBytes) < chacha20poly1305.NonceSizeX {
+		return errors.New("ciphertext too short")
+	}
+
+	nonce := inBytes[:chacha20poly1305.NonceSizeX]
+	ciphertext := inBytes[chacha20poly1305.NonceSizeX:]
+
+	plaintext, err := aead.Open(nil, nonce, ciphertext, aad)
+	if err != nil {
+		return fmt.Errorf("decrypt/auth failed: %w", err)
+	}
+
+	if err := os.WriteFile(outPath, plaintext, 0640); err != nil {
+		return fmt.Errorf("write output: %w", err)
+	}
+	return nil
+}