Your digital assets are more vulnerable you might think. They could be stolen by hackers, extorted by the mob, expropriated by the government, or lost by you! #SmartCustody details what you need to ensure that you don't lose your Bitcoins, your Ether, or your self-sovereign identity. It teaches you how to protect your digital data and cryptocurrencies with procedural solutions. A risk-modeling methodology leads you through the process of sketching out your digital-asset processes, identifying your vulnerabilities, determining your true risks, and correcting those dangers. It's built upon a 14-step cold-storage scenario and a set of 27 personified adversaries. Case studies help to make the adversaries real, and identify both abstract and historic attacks for each. If you're a small Bitcoin holder, a cryptocurrency trader, or a small fund manager, #SmartCustody can offer you procedural techniques and adversarial insights to improve the security of your digital assets.