X-Git-Url: http://www.git.cypherpunks.ru/?a=blobdiff_plain;f=doc%2Feblob.texi;h=256e6d1e0dcc787677730f2a64c3bb91d80908ae;hb=0fad171c0d79ad583c0faf5427e22d1d62a0a52d;hp=ff637e4fd0f0854715be7ae12c7323a0447fc105;hpb=e3bc095b1863c3f5e105742ae30156d18e9c297a;p=nncp.git

diff --git a/doc/eblob.texi b/doc/eblob.texi
index ff637e4..256e6d1 100644
--- 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
@@ -50,15 +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
 
-Blob's encryption is done using @url{https://cr.yp.to/chacha.html,
-ChaCha20} algorithm. Data is splitted on 128 KiB blocks. Each block is
-encrypted with increasing nonce counter. @code{balloon(BLAKE2b-256, S,
-T, P, salt, password)} gives the main key, that is fed to
-@url{https://blake2.net/, BLAKE2Xb} XOF Actual encryption key for
-ChaCha20 and authentication key for MAC are derived from that XOF.
+@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 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 divided 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