From 73097b61d310ec224f8e917a0193d9a4200ec102 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niels=20M=C3=B6ller?= <nisse@lysator.liu.se>
Date: Wed, 7 Sep 2016 22:06:43 +0200
Subject: [PATCH] Document memeql_sec.
---
ChangeLog | 1 +
nettle.texinfo | 13 +++++++++++--
2 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index a4548bc9..96ed1f0f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,6 +1,7 @@
2016-09-07 Niels Möller <nisse@lysator.liu.se>
* nettle.texinfo (Elliptic curves): Split into sub-nodes.
+ (Miscellaneous functions): Document memeql_sec.
2016-09-06 Niels Möller <nisse@lysator.liu.se>
diff --git a/nettle.texinfo b/nettle.texinfo
index 291ebcec..3ea0600a 100644
--- a/nettle.texinfo
+++ b/nettle.texinfo
@@ -4207,7 +4207,8 @@ it. If you have a process operating on the secret data, and this process
does memory accesses depending on the data, e.g, an internal lookup
table in some cryptographic algorithm, an attacker running a separate
process on the same system may use behavior of internal CPU caches to
-get information about your secrets.
+get information about your secrets. This type of attack can even cross
+virtual machine boundaries.
@end itemize
Nettle's ECC implementation is designed to be @dfn{side-channel silent},
@@ -4937,8 +4938,16 @@ Like @code{memxor}, but takes two source areas and separate
destination area.
@end deftypefun
+@deftypefun int memeql_sec (const void *@var{a}, const void *@var{b}, size_t @var{n})
+Side-channel silent comparison of the @var{n} bytes at @var{a} and
+@var{b}. I.e., instructions executed and memory accesses are identical
+no matter where the areas differ, @pxref{Side-channel silence}. Return
+non-zero if the areas are equal, and zero if they differ.
+@end deftypefun
-@code{memxor} is declared in @file{<nettle/memxor.h>}.
+These functions are declared in @file{<nettle/memops.h>}. For
+compatibility with earlier versions of Nettle, @code{memxor} and
+@code{memxor3} are also declared in @file{<nettle/memxor.h>}.
@node Compatibility functions, , Miscellaneous functions, Reference
@comment node-name, next, previous, up
--
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