[tor-commits] [torspec/master] Update our MAC definition to include the key len.

asn at torproject.org asn at torproject.org
Mon Mar 13 14:48:08 UTC 2017

commit 33bcbe24d6d526a347b74c3678f700da5f1a6e54
Author: George Kadianakis <desnacked at riseup.net>
Date:   Thu Mar 9 16:56:33 2017 +0200

    Update our MAC definition to include the key len.
    It was recently changed to include the key len as first argument, but
    the spec was never updated. See the following gitlab review comment for
    more info:
 proposals/224-rend-spec-ng.txt | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/proposals/224-rend-spec-ng.txt b/proposals/224-rend-spec-ng.txt
index ae990d4..8bff173 100644
--- a/proposals/224-rend-spec-ng.txt
+++ b/proposals/224-rend-spec-ng.txt
@@ -209,10 +209,11 @@ Table of contents:
       * Instantiate H with SHA3-256.
-      * Instantiate MAC(key=k, message=m) with H(k || m).
       * Instantiate KDF with SHAKE-256.
+      * Instantiate MAC(key=k, message=m) with H(k_len || k || m),
+        where k_len is htonll(len(k)).
    For legacy purposes, we specify compatibility with older versions of
    the Tor introduction point and rendezvous point protocols. These used
    RSA1024, DH1024, AES128, and SHA1, as discussed in

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