Check out OpenLedger, if they still provide a white label solution. It was quite flexible and has a robust engine.

Otherwise, you have Opendax or Bleeders as alternatives and a few others but I don't know much about it, nor a platform currently using any.
I believe Opendax's code is public and is known to be from a reliable company in the blockchain niche.

Choose wisely, because you can't mess with the security platform...