Remove a = 0 special-case in BN_mod_exp_mont.
BN_mod_exp_mont is intended to protect the base, but not the exponent.
Accordingly, it shouldn't treat a base of zero as special.
Change-Id: Ib053e8ce65ab1741973a9f9bfeff8c353567439c
Reviewed-on: https://boringssl-review.googlesource.com/27284
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/crypto/fipsmodule/bn/exponentiation.c b/crypto/fipsmodule/bn/exponentiation.c
index c85c00b..12bc6e8 100644
--- a/crypto/fipsmodule/bn/exponentiation.c
+++ b/crypto/fipsmodule/bn/exponentiation.c
@@ -639,12 +639,6 @@
aa = a;
}
- if (BN_is_zero(aa)) {
- BN_zero(rr);
- ret = 1;
- goto err;
- }
-
// We exponentiate by looking at sliding windows of the exponent and
// precomputing powers of |aa|. Windows may be shifted so they always end on a
// set bit, so only precompute odd powers. We compute val[i] = aa^(2*i + 1)
