AEAD encryption mode and new encrypted packet format

[nncp.git] / doc / eblob.texi

diff --git a/doc/eblob.texi b/doc/eblob.texi
index 74e6661021ff879bbfa312684c6bde892f4d8d9f..45de886d3defe40b7a82905107f64a79293d02ca 100644 (file)
--- a/doc/eblob.texi
+++ b/doc/eblob.texi
@@ -32,16 +32,16 @@ winner).
 Eblob is an @url{https://tools.ietf.org/html/rfc4506, XDR}-encoded structure:
 
 @verbatim
-+-------+------------------+------------+
-| MAGIC | S | T | P | SALT | BLOB | MAC |
-+-------+------------------+------------+
++-------+------------------+------+
+| MAGIC | S | T | P | SALT | BLOB |
++-------+------------------+------+
 @end verbatim
 
 @multitable @columnfractions 0.2 0.3 0.5
 @headitem @tab XDR type @tab Value
 @item Magic number @tab
     8-byte, fixed length opaque data @tab
-    @verb{|N N C P B 0x00 0x00 0x02|}
+    @verb{|N N C P B 0x00 0x00 0x03|}
 @item S, T, P @tab
     unsigned integer @tab
     Space cost, time cost and parallel jobs number
@@ -50,22 +50,19 @@ Eblob is an @url{https://tools.ietf.org/html/rfc4506, XDR}-encoded structure:
     Randomly generated salt
 @item Blob @tab
     variable length opaque data @tab
-    Encrypted data itself
-@item MAC @tab
-    32 bytes, fixed length opaque data @tab
-    BLAKE2b-256 MAC of encrypted blob
+    Authenticated and Encrypted data itself
 @end multitable
 
 @enumerate
 @item generate the main key using @code{balloon(BLAKE2b-256, S, T, P,
 salt, password)}
 @item initialize @url{https://blake2.net/, BLAKE2Xb} XOF with generated
-main key and 96-byte output length
-@item feed @verb{|N N C P B 0x00 0x00 0x02|} magic number to XOF
-@item read 32-bytes of blob encryption key
-@item read 64-bytes of blob authentication key
-@item encrypt the blob using @url{https://cr.yp.to/chacha.html,
-ChaCha20}. Blob is splitted on 128 KiB blocks. Each block is encrypted
-with increasing nonce counter
-@item authenticate ciphertext with MAC
+main key and 32-byte output length
+@item feed @verb{|N N C P B 0x00 0x00 0x03|} magic number to XOF
+@item read 32-bytes of blob AEAD encryption key
+@item encrypt and authenticate blob using
+    @url{https://cr.yp.to/chacha.html, ChaCha20}-@url{https://en.wikipedia.org/wiki/Poly1305, Poly1305}.
+    Blob is splitted on 128 KiB blocks. Each block is encrypted with
+    increasing nonce counter. Eblob packet itself, with empty blob
+    field, is fed as an additional authenticated data
 @end enumerate