This document discusses the threats, risks, and controls related to:

— systems that provide digital asset custodian services and/or exchange services to their customers (consumers and businesses) and management of security when an incident occurs;

— asset information (including the signature key of the digital asset) that a custodian of digital assets manages.

This document is addressed to digital asset custodians that manage signature keys associated with digital asset accounts. In such a case, certain specific recommendations apply.

The following is out of scope of this document:

— core security controls of blockchain and DLT systems;

— business risks of digital asset custodians;

— segregation of customer's assets;

— governance and management issues.