BetKing is a popular bitcoin dice site that has revealed how they keep over 5000 of their players bitcoin secure from hackers. The main feature in their armour is the popular Trezor hardware wallet that you can buy for about $99 dollars from the Trezor website. Here's a quick summary of the precautions that they take... BetKing prefer Trezor over using air gapped computers because Trezors can't be hacked or infected with malware. BetKing create multiple wallets and divide the BTC between wallets so if one wallet is compromised only a portion of player funds will be lost. They use cold, intermediate and hot wallets to limit exposure. A computer with no Wifi, internet, bluetooth or sound is used to encrypt the Trezor seed. The encrypted seed is then split into 9 parts. Any 6 will allow you to fully recover the seed. The 9 parts are copied onto a USB key and printed out. The computer used to print the seed is then destroyed.