fix an undefined use of gmp functions

diff --git a/d0_blind_id.c b/d0_blind_id.c
index 614f49a217ddd81fa4caa145dc85d847932e8490..c71c88befad21c3b9a15cc27f22a61d11f4fb71f 100644 (file)
--- a/d0_blind_id.c
+++ b/d0_blind_id.c
@@ -921,8 +921,8 @@ WARN_UNUSED_RESULT BOOL d0_blind_id_authenticate_with_private_id_verify(d0_blind
 
        // verify schnorr ID scheme
        // we need 4^r = 4^temp0 (g^s)^-challenge
-       CHECK(d0_bignum_neg(temp1, ctx->challenge));
-       CHECK(d0_bignum_mod_pow(temp2, ctx->schnorr_g_to_s, temp1, ctx->schnorr_G));
+       CHECK(d0_bignum_mod_inv(temp1, ctx->schnorr_g_to_s, ctx->schnorr_G));
+       CHECK(d0_bignum_mod_pow(temp2, temp1, ctx->challenge, ctx->schnorr_G));
        CHECK(d0_bignum_mod_pow(temp1, four, temp0, ctx->schnorr_G));
        CHECK_ASSIGN(temp3, d0_bignum_mod_mul(temp3, temp1, temp2, ctx->schnorr_G));