Virtual Asset Custody: How Banks Maintain Control over Digital Assets

As stablecoins, tokenized real-world assets (RWAs), and other tokenized financial products gradually enter the market, financial institutions are facing a very practical question:

How can on-chain assets be held in secure custody?

When it comes to virtual asset custody, many people first think of cold wallets, HSMs (hardware security modules), MPC (multi-party computation), or how to protect private keys.

For banks, however, the real challenge is not just "where the private keys are stored," but rather:

Who can move the assets, under what circumstances, what approvals are required, and whether every operation can be fully traced.

This is the biggest difference between institutional-grade virtual asset custody and an ordinary personal wallet.

Custody Is Becoming Infrastructure for Digital Finance

This is no longer an issue that concerns only virtual asset service providers.

In recent years, major international financial institutions, including BNY, State Street, and Deutsche Bank, have successively moved into digital asset custody.

BNY, one of the world's leading asset servicing and custody banks, has extended its digital asset custody to the safekeeping and transfer of the stablecoin USDC, along with related cash services.

State Street has likewise incorporated wallet management, asset custody, and cash management capabilities into its digital asset platform, as a foundation for future support of tokenized funds, stablecoins, and other digital asset services.

Deutsche Bank, meanwhile, continues to advance digital asset custody services for institutional and corporate clients.

The moves by these major institutions reflect a clear trend:

Virtual asset custody is evolving from simply "safekeeping assets" into a foundational capability for banks developing stablecoins, RWAs, and other on-chain financial services.

If banks cannot first securely manage control over on-chain assets, subsequent payment, trading, settlement, and tokenization services will be difficult to put into practice.

What Banks Really Manage Is Control over Assets

Traditional finance already has mature systems for permissions, authorization, accounting, and auditing.

Virtual assets do not overturn these systems entirely; rather, they add new objects of control: private keys, wallet addresses, and on-chain transactions.

An institutional-grade custody capability therefore needs to address at least three layers.

The first is Key: private key security.
How private keys are generated, stored, backed up, and used should all take place in a protected environment, reducing the risk of any single individual or general-purpose system directly accessing them.

The second is Policy: transaction rules and permissions.
Who can initiate a transaction, which amounts require a higher approval tier, which addresses are permitted for transfers, and whether operations can be suspended under abnormal conditions: all of these rules need to be established in advance.

The third is Accountability: records and auditing.
Every transaction, from initiation, review, and signing to final on-chain confirmation, should leave a complete record that the financial institution can trace and verify.

In other words, safeguarding private keys is only the first step. True institutional-grade custody brings keys, permissions, and auditing together under a single governance framework.

Taiwan's Regulatory Direction Is Shifting from "Safekeeping" to "Control"

With the promulgation of the Virtual Asset Service Act, Taiwan's regulatory direction on virtual asset custody is becoming clearer. The effective date of the new law is yet to be set by the Executive Yuan, and further details will be clarified through subsequent subsidiary regulations.

Notably, the new framework's understanding of "custody" goes beyond simply placing assets in a wallet. It also covers managing virtual assets and managing the tools used to control them.

The framework further requires the segregation of client assets from the provider's own assets, along with reconciliation, record retention, and related internal controls.

Qualified financial institutions may also apply to conduct virtual asset-related business in the future.

This means that if banks enter the virtual asset market, they need to build not just a wallet system, but an asset management capability that can be integrated into their existing compliance, risk management, information security, and audit frameworks.

The international regulatory direction is similar.

Whether it is U.S. banking regulators' requirements for third-party custody or the Basel Committee on Banking Supervision's approach to operational and technology risks related to crypto-assets, both reflect the same core principle:

Technology can be supported by external parties, but the financial institution's own governance responsibility remains.

Cold, Warm, and Hot Wallets Are Really About Tiered Asset Management

Not all virtual assets held by a financial institution are used in the same way.

Assets held long term and rarely moved can be kept under a higher degree of isolation. Assets needed for daily operations must balance security and efficiency. Assets for payments or trading that require greater immediacy have different liquidity needs.

Therefore, what cold, warm, and hot wallets really address is not only "which one is more secure," but:

Which tier assets for different purposes should sit in, how much balance to maintain at each tier, who operates them, and what authorizations are required when assets move between tiers.

This is another key difference between institutional custody and an ordinary wallet.

From Custody Capability to M-Key

BlockChain Security's M-Key was built from these very needs.

M-Key is a virtual asset security vault for financial institutions, governments, and enterprises. It manages assets in cold, warm, and hot tiers according to usage needs, and combines HSM (hardware security module), TEE (trusted execution environment), identity verification, access control, and multi-level approval mechanisms to help institutions establish a complete asset operation workflow.

HSM primarily protects private keys and the signing environment, while TEE further protects critical transactions and execution processes.

For financial institutions, what truly matters is not how many security technologies are used, but whether those technologies map back to real management needs:

What M-Key sets out to solve, therefore, is not merely "building a virtual asset wallet for banks."

More importantly, it helps financial institutions keep asset control, operational permissions, and governance processes within their own management framework as they move into on-chain finance.

Custody Is the Foundation for the Next Stage of Digital Finance

When people talk about virtual asset custody today, the first things that come to mind may be BTC, ETH, or stablecoins.

But as financial assets gradually become tokenized, the on-chain assets that need to be managed in the future may also include tokenized funds, bonds, RWAs, and many other assets that originally existed in traditional financial markets.

The form of assets will change, but the core question financial institutions face remains the same:

Who has the authority to control assets, and can that control process be securely managed, traced, and audited?

The virtual asset custody capability that banks build today is therefore not just a long-term capability to "hold cryptocurrency."

It is more likely to become the shared digital asset control and governance infrastructure for financial institutions as they develop stablecoins, RWAs, and other on-chain financial services.

With deep expertise in virtual asset security and forensics, BlockChain Security (BCS) helps financial institutions, governments, and enterprises build tiered custody architectures across cold, warm, and hot wallets through M-Key. By integrating key protection, access control, and audit records into existing compliance and risk management processes, BCS supports institutions in laying a solid foundation for on-chain finance.