1 files changed, 47 insertions, 0 deletions
diff --git a/lib/liboqs/src/kem/kyber/pqcrystals-kyber_kyber1024_ref/verify.c b/lib/liboqs/src/kem/kyber/pqcrystals-kyber_kyber1024_ref/verify.c
new file mode 100644
index 000000000..ed4a6541f
--- /dev/null
+++ b/lib/liboqs/src/kem/kyber/pqcrystals-kyber_kyber1024_ref/verify.c
@@ -0,0 +1,47 @@
+#include <stddef.h>
+#include <stdint.h>
+#include "verify.h"
+
+/*************************************************
+* Name:        verify
+*
+* Description: Compare two arrays for equality in constant time.
+*
+* Arguments:   const uint8_t *a: pointer to first byte array
+*              const uint8_t *b: pointer to second byte array
+*              size_t len:       length of the byte arrays
+*
+* Returns 0 if the byte arrays are equal, 1 otherwise
+**************************************************/
+int verify(const uint8_t *a, const uint8_t *b, size_t len)
+{
+  size_t i;
+  uint8_t r = 0;
+
+  for(i=0;i<len;i++)
+    r |= a[i] ^ b[i];
+
+  return (-(uint64_t)r) >> 63;
+}
+
+/*************************************************
+* Name:        cmov
+*
+* Description: Copy len bytes from x to r if b is 1;
+*              don't modify x if b is 0. Requires b to be in {0,1};
+*              assumes two's complement representation of negative integers.
+*              Runs in constant time.
+*
+* Arguments:   uint8_t *r:       pointer to output byte array
+*              const uint8_t *x: pointer to input byte array
+*              size_t len:       Amount of bytes to be copied
+*              uint8_t b:        Condition bit; has to be in {0,1}
+**************************************************/
+void cmov(uint8_t *r, const uint8_t *x, size_t len, uint8_t b)
+{
+  size_t i;
+
+  b = -b;
+  for(i=0;i<len;i++)
+    r[i] ^= b & (r[i] ^ x[i]);
+}