diff options
| -rw-r--r-- | chip/g/dcrypto/bn.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/chip/g/dcrypto/bn.c b/chip/g/dcrypto/bn.c index 788393d96f..bff4f5b996 100644 --- a/chip/g/dcrypto/bn.c +++ b/chip/g/dcrypto/bn.c @@ -343,6 +343,10 @@ void bn_mont_modexp(struct BIGNUM *output, const struct BIGNUM *input, if (bn_bits(N) == 2048 || bn_bits(N) == 1024) { /* TODO(ngm): add hardware support for standard key sizes. */ bn_mont_modexp_asm(output, input, exp, N); + /* Final reduce. */ + /* TODO(ngm): constant time. */ + if (bn_sub(output, N)) + bn_add(output, N); return; } @@ -380,6 +384,7 @@ void bn_mont_modexp(struct BIGNUM *output, const struct BIGNUM *input, *output = acc; } + /* TODO(ngm): constant time. */ if (bn_sub(output, N)) bn_add(output, N); /* Final reduce. */ output->dmax = N->dmax; |