At Arcsys, we live and breathe digital preservation. Our core mission is ensuring the long-term safety, accessibility, and integrity of valuable digital assets. A huge part of that mission relies on trust – trust that records haven’t been tampered with, trust in the actions taken over time, trust in the entire preservation process. This demands robust traceability.
Naturally, we keep a close eye on emerging technologies that claim to enhance trust and transparency. Blockchain, with its promises of immutable, decentralized ledgers, frequently comes up in discussions about audit trails and proving data integrity.
So, we asked ourselves: Could blockchain serve as a valuable add-on to a dedicated digital preservation system like Arcsys, specifically to bolster traceability? Could logging key preservation events (like ingest checksums, fixity checks, migrations, or access logs) onto a blockchain provide a superior layer of proof?
After careful evaluation, our conclusion is clear: While interesting, blockchain currently introduces more significant drawbacks than benefits for this specific traceability use case, especially when compared to robust, integrated methods. Here’s why:
1. Is the Cost Worth the Traceability Gain?
Using a public blockchain means paying transaction fees (“gas”) for every event logged. For a large archive generating potentially millions of preservation events (every ingest, every fixity check, every format migration) over decades, these costs add up. Worse, fees on popular blockchains are notoriously volatile, making long-term budgeting nearly impossible. Even private/permissioned blockchains have infrastructure, maintenance, and governance costs.
- The Question: Is this significant, ongoing expense justified just for an external traceability layer, when strong internal mechanisms exist?
2. Scalability: Handling the Volume of Preservation Events
Digital preservation systems generate a lot of activity that needs logging for a complete audit trail. Can public blockchains, often limited in transactions per second (TPS), handle this constant stream of events from multiple large archives without creating bottlenecks or delays? Pushing large volumes of log data might require complex batching or off-chain aggregation, adding another layer of complexity.
- The Question: Can blockchain realistically scale to meet the traceability demands of active, large-scale digital archives?
3. “Immutability” vs. Archival Permanence Needs
Blockchain’s immutability relies on network consensus and current cryptography. As the Ethereum DAO hack showed, history can be altered under certain conditions. Furthermore, the long-term threat of quantum computing potentially breaking today’s crypto raises questions about the perpetual reliability of blockchain-based logs over the centuries archives must plan for.
- The Question: Is blockchain’s conditional immutability truly sufficient for an archival audit trail meant to last indefinitely? Does it introduce unacceptable long-term risks?
4. Environmental Concerns Remain
Even if only logging small bits of data (hashes, metadata), using energy-intensive Proof of Work blockchains for traceability contributes to a significant environmental footprint. While Proof of Stake is much better, it still requires infrastructure.
- The Question: Is the environmental impact justifiable for just the traceability function, if greener alternatives achieve the same goal?
5. Added Complexity and Technology Dependence
Integrating blockchain adds another complex technological layer to the preservation stack. This means more systems to manage, monitor, maintain, and migrate over time. It creates a dependency on the chosen blockchain platform’s longevity, security, and evolution – factors outside the archive’s control. What happens if the platform fades or fails?
- The Question: Does adding blockchain introduce more points of failure and long-term management headaches than it solves for traceability?
The Power of Integrated, Proven Methods
Crucially, robust digital preservation systems like Arcsys already incorporate strong mechanisms for traceability and integrity, designed specifically for the archival context:
- Secure Internal Journaling (Hash Chaining): Arcsys utilizes techniques like journal chaining. Essentially, logs of system events are cryptographically linked together (each new log entry contains a hash of the previous one). This creates a tamper-evident chain within the controlled preservation environment. Any attempt to alter a past log breaks the chain and is immediately detectable.
- Efficiency and Control: This internal method is highly efficient (no external transaction fees, minimal energy use), scalable, and keeps sensitive log data within the secure perimeter of the archive, aiding compliance (like GDPR).
- Integrated Fixity Checks: Regular cryptographic hashing (e.g., SHA-256) of the archived objects themselves, with results recorded in the secure journal, verifies that the objects haven’t changed.
- Secure Timestamps & Audit Trails: All actions are logged with secure timestamps and user information, providing a complete, verifiable history of the object’s lifecycle within the system.
Our Conclusion: Focus on Robust Architecture
While we continue to monitor blockchain developments, its current state presents too many challenges regarding cost, scalability, true long-term permanence, environmental impact, and complexity to be adopted merely for traceability within our digital preservation solutions.
The traceability provided by well-designed internal mechanisms like secure journaling (hash chaining), combined with standard cryptographic best practices, offers a more reliable, sustainable, efficient, and controllable way to ensure trust and integrity in digital archives. At Arcsys, our focus remains on strengthening these core, integrated features within a dedicated, robust preservation architecture.