Use const time reductions in Barrett and LCM computations

1 files changed, 17 insertions, 0 deletions

diff --git a/src/lib/math/bigint/divide.h b/src/lib/math/bigint/divide.h
index ac9c43e81..e365dabb3 100644
--- a/src/lib/math/bigint/divide.h
+++ b/src/lib/math/bigint/divide.h
@@ -48,6 +48,23 @@ void BOTAN_PUBLIC_API(2,9) ct_divide(const BigInt& x,
 *
 * @param x an integer
 * @param y a non-zero integer
+* @return x/y with remainder discarded
+*/
+inline BigInt ct_divide(const BigInt& x, const BigInt& y)
+   {
+   BigInt q, r;
+   ct_divide(x, y, q, r);
+   return q;
+   }
+
+/**
+* BigInt division, const time variant
+*
+* This runs with control flow independent of the values of x/y.
+* Warning: the loop bounds still leak the sizes of x and y.
+*
+* @param x an integer
+* @param y a non-zero integer
 * @param q will be set to x / y
 * @param r will be set to x % y
 */