bn: Use int instead of u32 for sizes

The loops relied on unsigned integer overflow, which is not immediately
obvious. Replace them with less clever variants that are clearer.

Also implement bn_compare using std::memcmp.
This commit is contained in:
Léo Lam
2018-05-16 00:27:43 +02:00
parent 56e91bfdc1
commit b9dd94b9b2
2 changed files with 34 additions and 53 deletions

View File

@ -8,9 +8,9 @@
// bignum arithmetic
int bn_compare(const u8* a, const u8* b, u32 n);
void bn_sub_modulus(u8* a, const u8* N, u32 n);
void bn_add(u8* d, const u8* a, const u8* b, const u8* N, u32 n);
void bn_mul(u8* d, const u8* a, const u8* b, const u8* N, u32 n);
void bn_inv(u8* d, const u8* a, const u8* N, u32 n); // only for prime N
void bn_exp(u8* d, const u8* a, const u8* N, u32 n, const u8* e, u32 en);
int bn_compare(const u8* a, const u8* b, int n);
void bn_sub_modulus(u8* a, const u8* N, int n);
void bn_add(u8* d, const u8* a, const u8* b, const u8* N, int n);
void bn_mul(u8* d, const u8* a, const u8* b, const u8* N, int n);
void bn_inv(u8* d, const u8* a, const u8* N, int n); // only for prime N
void bn_exp(u8* d, const u8* a, const u8* N, int n, const u8* e, int en);