diff options
author | Moxie Marlinspike <moxie@thoughtcrime.org> | 2014-11-24 12:54:30 -0800 |
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committer | Moxie Marlinspike <moxie@thoughtcrime.org> | 2014-11-24 12:54:30 -0800 |
commit | 60800e155612bea797eed93c67046a23d26054cc (patch) | |
tree | d88368c1c26162e27e790195133ca2b526597afe /jni/ed25519/fe_isnonzero.c |
Break out into separate repo.
Diffstat (limited to 'jni/ed25519/fe_isnonzero.c')
-rw-r--r-- | jni/ed25519/fe_isnonzero.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/jni/ed25519/fe_isnonzero.c b/jni/ed25519/fe_isnonzero.c new file mode 100644 index 00000000..47568001 --- /dev/null +++ b/jni/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); +} |