diff --git a/src/KeyKeeper/PasswordStore/FileFormatConstants.cs b/src/KeyKeeper/PasswordStore/FileFormatConstants.cs
index e76ebe2..6f755f7 100644
--- a/src/KeyKeeper/PasswordStore/FileFormatConstants.cs
+++ b/src/KeyKeeper/PasswordStore/FileFormatConstants.cs
@@ -1,3 +1,5 @@
+using System.Security.Cryptography;
+
 namespace KeyKeeper.PasswordStore;
 
 static class FileFormatConstants
@@ -8,4 +10,5 @@ static class FileFormatConstants
     public const int MAX_AESKDF_ROUNDS = 65536;
     public const byte ENCRYPT_ALGO_AES = 14;
     public const byte KDF_TYPE_AESKDF = 195;
+    public const int HMAC_SIZE = HMACSHA3_512.HashSizeInBytes;
 }
\ No newline at end of file