updates.

[silc.git] / doc / draft-riikonen-silc-pp-01.nroff

diff --git a/doc/draft-riikonen-silc-pp-01.nroff b/doc/draft-riikonen-silc-pp-01.nroff
index 0fa63ff2ed3928e013a014f874a6a8a874121b8e..a8d9194720751c97d39e538ef98a712c081e0d4e 100644 (file)
--- a/doc/draft-riikonen-silc-pp-01.nroff
+++ b/doc/draft-riikonen-silc-pp-01.nroff
@@ -1308,6 +1308,10 @@ represents the Channel Message Payload.
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
+~                              MAC                              ~
+|                                                               |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                                                               |
 ~                       Initial Vector *                        ~
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
@@ -1333,6 +1337,16 @@ o Padding (variable length) - The padding that must be
   applied because this payload is encrypted separately from
   other parts of the packet.
 
+o MAC (variable legnth) - The MAC computed from the
+  Message Length, Message Data, Padding Length and Padding
+  fields.  This protects the integrity of the plaintext
+  channel message.  The receiver can verify from the MAC
+  whether the message decrypted correctly.  Also, if more than
+  one private key has been set for the channel, the receiver
+  can verify which of the keys decrypted the message 
+  correctly.  Note that, this field is encrypted and must
+  be added to the padding calculation.
+
 o Initial Vector (variable length) - The initial vector
   that has been used in packet encryption.  It needs to be
   used in the packet decryption as well.  What this field
@@ -1543,6 +1557,12 @@ diagram represents the Private Message Key Payload.
 ~                      Private Message Key                      ~
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|      Cipher Name Length       |                               |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
+|                                                               |
+~                          Cipher Name                          ~
+|                                                               |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 .in 3
 
 .ce
@@ -1557,8 +1577,16 @@ o Private Message Key Length (2 bytes) - Indicates the length
   any other field.
 
 o Private Message Key (variable length) - The actual private
-  message key material.  This key is used as such as key material 
-  for encryption function.
+  message key material.
+
+o Cipher Name Length (2 bytes) - Indicates the length of the
+  Cipher Name field in the payload, not including any other
+  field.
+
+o Cipher Name (variable length) - Name of the cipher to use
+  in the private message encryption.  If this field does not
+  exist then the default cipher of the SILC protocol is used.
+  See the [SILC1] for defined ciphers.
 .in 3
 
 
@@ -1972,10 +2000,9 @@ After the key material has been received from the SKE protocol it is
 processed as the [SILC3] describes.  If the key material is used as
 channel private key then the Sending Encryption Key, as defined in
 [SILC3] is used as the channel private key.  Other key material must
-be discarded.  If the key material is used as private message key then
-the keys and the IV's are used as defined in the [SILC3].  The HMAC
-key, however, must be discarded.  Any other use for the key material
-is undefined.
+be discarded.  The [SILC1] defines the way to use the key material if
+it is intended to be used as private message keys.  Any other use for
+the key material is undefined.
 
 
 .ti 0
@@ -2067,7 +2094,7 @@ As the receiver founds the packet to be channel message, rest of the
 packet processing is special.  Rest of the SILC Packet header is
 decrypted with the same session key along with the padding of the
 packet.  After that the packet is protected with the channel specific
-key and hence can be decrypted only if the receiver is the client on
+key and thus can be decrypted only if the receiver is the client on
 the channel.  See section 2.7 Packet Padding Generation for more
 information about padding on special packets.