1 files changed, 5 insertions, 0 deletions
diff --git a/src/modes/aead/aead.h b/src/modes/aead/aead.h
index 25958a36a..d03cb295d 100644
--- a/src/modes/aead/aead.h
+++ b/src/modes/aead/aead.h
@@ -49,6 +49,11 @@ class BOTAN_DLL AEAD_Mode : public Cipher_Mode
       * modes, and large enough that random collisions are unlikely).
       */
       size_t default_nonce_size() const override { return 12; }
+
+      /**
+      * Return the size of the authentication tag used (in bytes)
+      */
+      virtual size_t tag_size() const = 0;
    };
 
 /**