-algorithms. Data is divided on 128 KiB blocks. Each block is encrypted with
-increasing nonce counter.
-
-Authenticated and encrypted size come after the header:
-
-@multitable @columnfractions 0.2 0.3 0.5
-@headitem @tab XDR type @tab Value
-@item Size @tab
- unsigned hyper integer @tab
- Payload size.
-@end multitable
+algorithms. Authenticated data is BLAKE3-256 hash of the unsigned
+portion of the header (the same data used in the signature). Size is
+XDR-encoded unsigned hyper integer, carrying the payload size, encrypted
+as a single AEAD-block (with the tag) independently from the following
+blocks. It is encoded with the zero nonce.