diff --git a/README.md b/README.md
index 9563ecf..6f67a4a 100644
--- a/README.md
+++ b/README.md
@@ -72,7 +72,7 @@ File ext: `*.tinyenc`
 File format:
 
 ```text
-[TAG; 2 bytes; short; BE]
+[TAG; 2 bytes; short; BE; Always 1]
 [LENGTH; 4 bytes; int; BE]
 [META; LENGTH bytes]
 [ENCRYPTED_DATA; n bytes; AES/GCM]