fix(crypto): imporve handling of return value

crypto/zkp_bip340.c

@@ -294,9 +294,11 @@ int zkp_bip340_tweak_private_key(const uint8_t *internal_private_key,
   }
 
   secp256k1_keypair keypair = {0};
-  if (secp256k1_keypair_create(context_writable, &keypair,
-                               internal_private_key) != 1) {
-    result = -1;
+  if (result == 0) {
+    if (secp256k1_keypair_create(context_writable, &keypair,
+                                 internal_private_key) != 1) {
+      result = -1;
+    }
   }
 
   if (context_writable) {

crypto/zkp_context.c

@@ -71,7 +71,10 @@ int zkp_context_init(void) {
     return 1;
   }
 
-  secp256k1_context_writable_randomize(context);
+  if (secp256k1_context_writable_randomize(context) != 0) {
+    zkp_context_destroy();
+    return 1;
+  }
 
   atomic_flag_clear(&locked);