From f529efe21a486def8b65f5b9b5354560e5e513b9 Mon Sep 17 00:00:00 2001 From: Othmar Gsenger Date: Fri, 27 Apr 2007 15:45:39 +0000 Subject: encryption --- internet-draft-satp.html | 32 ++++++++++++++++++++++++++++++-- 1 file changed, 30 insertions(+), 2 deletions(-) (limited to 'internet-draft-satp.html') diff --git a/internet-draft-satp.html b/internet-draft-satp.html index ba9e4db..f0b1b8a 100644 --- a/internet-draft-satp.html +++ b/internet-draft-satp.html @@ -430,8 +430,36 @@ HEX

4.8.  Encryption

-

Encryption is done in the same way as for SRTP (Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. Norrman, “The Secure Real-time Transport Protocol (SRTP),” March 2004.) [1]. This section will only discuss some small changes that HAVE TO be made. Please read SRTP RFC3711 section 3-9 (Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. Norrman, “The Secure Real-time Transport Protocol (SRTP),” March 2004.) [1] for details. SSRC is replaced by the sender ID +

Encryption is done in the same way as for SRTP (Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. Norrman, “The Secure Real-time Transport Protocol (SRTP),” March 2004.) [1]. This section will only discuss some small changes that HAVE TO be made. Please read SRTP RFC3711 section 3-9 (Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. Norrman, “The Secure Real-time Transport Protocol (SRTP),” March 2004.) [1] for details.

+

The least significant bits of SSRC are replaced by the sender ID and the rest is filled with zeros. For the SRTP SEQ the 16 least significant bits of the SATP sequence number are used and the 16 most significant bits of the sequence number replace the 16 least significant bits of the SRTP ROC. +


+ + +

Difference between SRTP and SATP +

+        0                   1                   2                   3
+      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+     |                     SATP    sequence number                   |
+     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+                                    =
+     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+     | SRTP ROC least significant   |         SRTP SEQ               |
+     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+        0                   1                   2                   3
+      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+     |0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0|       SATP sender ID          |
+     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+                                    =
+     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+     |                           SRTP SSRC                           |
+     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
 Figure 7 
+

5.  Security Considerations

@@ -476,7 +504,7 @@ References   Othmar Gsenger   -Puerstingerstr 32/7 +Puerstingerstr 32   Saalfelden 5760   -- cgit v1.2.3