handle point at infinity

obscuren · Jan 20, 2015 · 20a95cb · 20a95cb
1 parent 29b4554
commit 20a95cb
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/secp256k1/src/impl/ecdsa.h b/secp256k1/src/impl/ecdsa.h
@@ -149,6 +149,8 @@ int static secp256k1_ecdsa_sig_recover(const secp256k1_ecdsa_sig_t *sig, secp256
     secp256k1_num_mod_mul(&u2, &rn, &sig->s, &c->order);
     secp256k1_gej_t qj;
     secp256k1_ecmult(&qj, &xj, &u2, &u1);
+    if (secp256k1_gej_is_infinity(&qj))
+        return 0;
     secp256k1_ge_set_gej(pubkey, &qj);
     secp256k1_num_free(&rn);
     secp256k1_num_free(&u1);