diff --git a/src/scalar.h b/src/scalar.h index 63c0d646a3..4b3c2998bb 100644 --- a/src/scalar.h +++ b/src/scalar.h @@ -99,4 +99,7 @@ static void secp256k1_scalar_mul_shift_var(secp256k1_scalar *r, const secp256k1_ /** If flag is true, set *r equal to *a; otherwise leave it. Constant-time. Both *r and *a must be initialized.*/ static void secp256k1_scalar_cmov(secp256k1_scalar *r, const secp256k1_scalar *a, int flag); +/** Check invariants on a scalar (no-op unless VERIFY is enabled). */ +static void secp256k1_scalar_verify(const secp256k1_scalar *r); + #endif /* SECP256K1_SCALAR_H */ diff --git a/src/scalar_impl.h b/src/scalar_impl.h index bed7f95fcb..77abb83659 100644 --- a/src/scalar_impl.h +++ b/src/scalar_impl.h @@ -33,6 +33,14 @@ static int secp256k1_scalar_set_b32_seckey(secp256k1_scalar *r, const unsigned c return (!overflow) & (!secp256k1_scalar_is_zero(r)); } +static void secp256k1_scalar_verify(const secp256k1_scalar *r) { +#ifdef VERIFY + VERIFY_CHECK(secp256k1_scalar_check_overflow(r) == 0); +#endif + + (void)r; +} + #if defined(EXHAUSTIVE_TEST_ORDER) /* Begin of section generated by sage/gen_exhaustive_groups.sage. */ # if EXHAUSTIVE_TEST_ORDER == 7