Two custody functions
Custody covers two distinct functions, and a deployment can assign them to different parties. Digital asset custody is the holding of the assets themselves. The custodian provides the bank with wallets and addresses it can use for digital assets such as stablecoins used for settlement between banks. It can also custody stablecoins on behalf of the bank’s clients and hold other digital asset balances whose positions are reflected on the core. This function can sit with a custody provider or with the bank itself: the Office of the Comptroller of the Currency has confirmed that national banks may provide custody for crypto assets. Key custody and signing is the protection and use of the private keys that control those assets. It covers key generation, storage, rotation, and the enforcement of the bank’s signing policy before any transaction is broadcast. This function usually sits with the custody provider, but a bank can perform it with its own hardware security modules. CTS never holds private keys in either arrangement. The two functions often come from the same provider, but they do not have to. A bank can custody its own digital assets while a provider performs signing, or hold its own keys for assets a provider safekeeps records for.Division of responsibility
CTS calls the custodian through its API when a transaction needs to be
signed. The custodian applies the bank’s own approval policy before signing.
This ensures that governance controls for a treasury movement continue to apply
when that movement happens on chain.
Where custody appears
Custody is invoked by three applications. The pattern is the same in each case: a custody provider is used whenever private keys are needed to hold or transfer digital assets on a network that an external party can also access.24/7 Payments
Settlement assets held in custody settle the gross interbank obligations that
accumulate as client payments clear.
Treasury Management and Programmable Asset Movement
External assets held in custody are moved under policy, on schedule or in
response to on-chain conditions.
Connecting a provider
What CTS expects from a custody provider and how an existing provider is
wired in.
Why not self-custody
A bank can custody its own digital assets and hold its own keys, and CTS supports both. In practice, most banks integrate a custodian for reasons that sit outside the technology:- Qualified custody may be required by the bank’s regulator for certain asset classes
- Insurance and loss coverage is easier to obtain against a custodian’s controls
- Key ceremony, hardware security module operations, and staff segregation are expensive to run to audit standard
- A custodian already supports the settlement networks the bank needs, so adding a network is a configuration change rather than an engineering project