[DOC] Encryptionless mode

[govpn.git] / doc / handshake.texi

diff --git a/doc/handshake.texi b/doc/handshake.texi
index 0fb850a3ee423af976ce3d32de80374d4fdd8767..29f59f8b44f989e3c2c23d2bd1a64d3cec32dd58 100644 (file)
--- a/doc/handshake.texi
+++ b/doc/handshake.texi
@@ -6,9 +6,10 @@
 Each handshake message ends with so called @code{IDtag}: it is an XTEA
 encrypted first 64 bits of each message with client's @ref{Identity} as
 a key. It is used to transmit identity and to mark packet as handshake
-message. Server can determine used identity by trying all possible known
-to him keys. It consumes resources, but XTEA is rather fast algorithm
-and handshake messages checking is seldom enough event.
+message.
+
+If @ref{Noise} is enabled, then junk data is inserted before
+@code{IDtag} to fill up packet to MTU's size.
 
 @strong{Preparation stage}:
 
@@ -33,7 +34,7 @@ symmetric encryption. @code{El()} is Elligator point encoding algorithm.
 @verb{|R + enc(H(DSAPub), R, El(CDHPub)) + IDtag -> Server|} [48 bytes]
 
 @item
-@itemize @bullet
+@itemize
 @item Server remembers client address.
 @item Decrypts @code{El(CDHPub)}.
 @item Inverts @code{El()} encoding and gets @code{CDHPub}.
@@ -47,7 +48,7 @@ symmetric encryption. @code{El()} is Elligator point encoding algorithm.
 @verb{|enc(H(DSAPub), R+1, El(SDHPub)) + enc(K, R, RS + SS) + IDtag -> Client|} [80 bytes]
 
 @item
-@itemize @bullet
+@itemize
 @item Client decrypts @code{El(SDHPub)}.
 @item Inverts @code{El()} encoding and gets @code{SDHPub}.
 @item Computes @code{K}.
@@ -62,7 +63,7 @@ symmetric encryption. @code{El()} is Elligator point encoding algorithm.
 @verb{|enc(K, R+1, RS + RC + SC + Sign(DSAPriv, K)) + IDtag -> Server|} [120 bytes]
 
 @item
-@itemize @bullet
+@itemize
     @item Server decrypts @code{RS}, @code{RC}, @code{SC},
     @code{Sign(DSAPriv, K)}.
 
@@ -80,7 +81,7 @@ symmetric encryption. @code{El()} is Elligator point encoding algorithm.
 @verb{|ENC(K, R+2, RC) + IDtag -> Client|} [16 bytes]
 
 @item
-@itemize @bullet
+@itemize
 @item Client decrypts @code{RC}
 @item Compares with its own one sent before.
 @item Computes final session encryption key as server did.
@@ -92,3 +93,6 @@ symmetric encryption. @code{El()} is Elligator point encoding algorithm.
 has 128-bit security margin and that is why are not in use except in
 handshake process. @code{R*} are required for handshake randomization
 and two-way authentication.
+
+In @ref{Encless, encryptionless mode} each @code{enc()} is replaced with
+AONT and chaffing function over the noised data.