How do we know Cloudflare isn't copying these random numbers?
It has an EV cert, but something this critical should probably have its TLS endpoint in a secure bunker.
Even more scary, shares a Cloudflare nameserver pair with a carding (credit card theft) forum.
A good site that offers random number generating services (dice rolling, coin flipping etc').
RANDOM.ORG offers true random numbers to anyone on the Internet. The randomness comes from atmospheric noise, which for many purposes is better than the pseudo-random number algorithms typically used in computer programs.