Man's Search for Privacy On-Chain

Many blockchains today provide full public access to activity occurring on the ledger. For financial institutions, this creates a problem.

Banks, asset managers, payment companies, and other institutions often cannot operate with complete transactional transparency. Client activity, balances, counterparties, settlement flows, and trading strategies need to remain confidential.

At the same time, institutions do not necessarily want to give up the benefits of public blockchains.

This creates a fundamental trade-off.

Public networks can provide liquidity, transparency, security, interoperability, and access to an existing ecosystem. Private infrastructure can provide confidentiality, greater control, and the ability to determine who can participate in the network.

Increasingly, institutions are looking for something in between.

The current landscape includes public blockchains, private blockchains, privacy layers, and public-private networks.

Each approach solves a different problem.

And each comes with trade-offs around liquidity, security, privacy, transparency, control, and long-term interoperability.

Public Blockchains Optimize for Openness

Public blockchains provide many of the characteristics that originally made blockchain infrastructure attractive.

They can offer broad participation, transparent transaction history, established consensus mechanisms, existing liquidity, and interoperability with applications already operating on the network.

However openness is in direct conflict with privacy.

If transactions, wallet balances, and asset movements are publicly visible, institutions have to determine whether that level of transparency is compatible for clients as well as regulatory requirements.

This usually means adding another layer of infrastructure.

One approach is to perform certain transactions off-chain and reconcile them on-chain in a way that limits the sensitive information being exposed.

Other approaches use cryptographic privacy technology.

In either case, privacy is something that has to be added rather than something that necessarily exists by default.

Each institution has to determine whether the liquidity and network effects of a public blockchain outweigh the additional work required to make it private enough for institutional use.

Private Blockchains Optimize for Control

Private blockchains take the opposite approach.

Access is limited to approved and whitelisted participants, giving the organization operating the network significantly more control over what occurs on-chain.

Depending on how the network is designed, that can include the ability to manage permissions, restrict activity, claw back funds, correct errors, or potentially reverse transactions.

Banks are built around the assumption that exceptional situations can be managed.

Transactions can be reviewed.

Accounts can be frozen.

Errors can be corrected.

Operational issues can be escalated.

A fully immutable system introduces a very different operating model.

Private infrastructure can allow institutions to retain more of the controls they already expect from traditional financial systems.

But greater control also introduces trade-offs.

A private network may have less external liquidity, fewer participants, reduced interoperability, and weaker network effects than a widely adopted public blockchain.

The institution has to decide whether the additional control is worth giving up some of the advantages of an open network.

Privacy Layers Try to Combine Both Models

Another approach is to introduce privacy on top of broader blockchain infrastructure through Fully Homomorphic Encryption (FHE).

Privacy-focused technologies can allow certain information or transactions to remain confidential while still using a public or widely distributed blockchain ecosystem.

The attraction for institutions is straightforward.

They may be able to retain access to the liquidity, consensus, infrastructure, and security of a broader network while deciding which information should remain private.

Not everything has to be hidden.

But not everything has to be public either.

An institution may want an asset to exist on broadly accessible infrastructure while preventing information about the holder, transaction amount, position, or counterparty from being publicly exposed.

This creates a potential middle ground.

But privacy layers also introduce another technology component that has to be governed and secured.

Institutions still need to determine who can see protected information, how compliance monitoring works, what information remains verifiable, and what happens if the privacy infrastructure fails.

Privacy does not eliminate institutional controls.

It changes how those controls are implemented.

Public-Private Networks Create Another Middle Ground

Public-private blockchain networks attempt to combine distributed ledger infrastructure with controls designed specifically for institutional use.

Rather than assuming that every transaction must be permanently irreversible and publicly visible, these networks can incorporate permissions, privacy, and exception-management capabilities.

Canton is one example of infrastructure developed around this type of institutional model.

The broader idea is important.

Financial institutions may want blockchain infrastructure without accepting every design principle of a fully public, permissionless network.

They may still require defined participants, transaction privacy, operational controls, regulatory oversight, and mechanisms for dealing with mistakes.

Public-private infrastructure attempts to build these requirements into the network itself.

The trade-off is that institutions still have to evaluate how open the network is, how much liquidity it can develop, and whether it will be interoperable with broader blockchain ecosystems over time.

Liquidity and Privacy Pull in Different Directions

One of the biggest tensions in blockchain infrastructure is between liquidity and privacy.

Liquidity generally benefits from broad participation.

The more institutions, investors, exchanges, market makers, and assets that exist within an ecosystem, the easier it can become to transact.

Public blockchain networks naturally benefit from this dynamic.

Privacy often pushes in the opposite direction.

Institutions may want fewer participants to see transactions, positions, balances, and counterparties.

A private network may provide greater confidentiality but also restrict the number of available participants and sources of liquidity.

This is why the decision is more complicated than simply choosing between public and private.

Institutions are choosing where they want to sit on a spectrum.

At one end is maximum liquidity and openness.

At the other is maximum control.

Most institutional use cases will require some combination of the two.

Institutions May Choose More Than One Path

These decisions do not necessarily require an institution to choose one architecture for every product.

One product may use public blockchain infrastructure because liquidity and distribution are the priority.

Another may use private or permissioned infrastructure because confidentiality and operational control matter more.

Some institutions may even pursue multiple approaches for similar products.

This can reduce dependence on a single infrastructure model while giving the institution experience with different architectures.

The result may be a blockchain strategy built around several networks rather than one.

Conclusion

There is no definitive best blockchain architecture for financial institutions today.

Every approach creates trade-offs.

The right decision depends on what the institution values most.

The answer today may involve more than one network.

The search for privacy on-chain is ultimately a search for balance: enough openness to benefit from blockchain infrastructure, and enough control to make that infrastructure usable by financial institutions.

Frequently Asked Questions