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authorGeorge Hazan <george.hazan@gmail.com>2016-01-26 08:28:32 +0000
committerGeorge Hazan <george.hazan@gmail.com>2016-01-26 08:28:32 +0000
commit2a82a9154f9d6e0b5658c82cd346051017339a1e (patch)
tree8321c2d1897d4026e68064241014eef4a57ddc9d /libs/libaxolotl/src/curve25519/ed25519/fe_isnonzero.c
parent80148955f82c205cc94f0112e0fbfe8f91bc4330 (diff)
libaxolotl - initial commit
git-svn-id: http://svn.miranda-ng.org/main/trunk@16169 1316c22d-e87f-b044-9b9b-93d7a3e3ba9c
Diffstat (limited to 'libs/libaxolotl/src/curve25519/ed25519/fe_isnonzero.c')
-rw-r--r--libs/libaxolotl/src/curve25519/ed25519/fe_isnonzero.c19
1 files changed, 19 insertions, 0 deletions
diff --git a/libs/libaxolotl/src/curve25519/ed25519/fe_isnonzero.c b/libs/libaxolotl/src/curve25519/ed25519/fe_isnonzero.c
new file mode 100644
index 0000000000..47568001ce
--- /dev/null
+++ b/libs/libaxolotl/src/curve25519/ed25519/fe_isnonzero.c
@@ -0,0 +1,19 @@
+#include "fe.h"
+#include "crypto_verify_32.h"
+
+/*
+return 1 if f == 0
+return 0 if f != 0
+
+Preconditions:
+ |f| bounded by 1.1*2^26,1.1*2^25,1.1*2^26,1.1*2^25,etc.
+*/
+
+static const unsigned char zero[32];
+
+int fe_isnonzero(const fe f)
+{
+ unsigned char s[32];
+ fe_tobytes(s,f);
+ return crypto_verify_32(s,zero);
+}