2019 Aug 29 Written by Shannon Appelcline
Proof of stake could endanger the equality of the blockchain and hidden centralizations could endanger its trustlessness. However, there’s another innovation that may endanger both…
Upon inventing Bitcoin, Satoshi Nakamoto created an open ledger that anyone could write to as long as they followed the consensus rules. This design revealed two crucial elements of blockchain design. First, it declared the equality of the blockchain: anyone could see anything on the blockchain thanks to its permissionless design; and anyone could add any valid transaction to the blockchain thanks to its censorship resistance. Second, it demonstrated the trustlessness of the blockchain: anyone could verify that both the blocks and their transactions were validly constructed.
But the founding principles of a community are constantly endangered as it grows and evolves. As we’ve written in past philosophy articles, we feel that proof of stake could endanger the equality of the blockchain and that hidden centralizations could endanger its trustlessness. However, there’s another innovation that may endanger both: secrecy.
There has been a bit of secrecy in Bitcoin from the start, as Satoshi Nakamoto states in the original paper: “The necessity to announce all transactions publicly precludes [traditional privacy, which limits information about an exchange to the parties involved and a trusted third party], but privacy can still be maintained by breaking the flow of information in another place: by keeping public keys anonymous.”
However, the blockchain is not truly anonymous. At best, it’s pseudonymous and even that’s quite fragile. It depends on strict key hygiene, where everyone constantly creates new keys, and even then there’s the danger of correlation if someone can detect clusters of addresses and connect any of them to a real-world identity.
The quest for privacy beyond Nakamoto’s pseudonymity has loomed large as Bitcoin has matured. In 2013, Greg Maxwell proposed CoinJoin as one of the first solutions; it simply mixed together bitcoins, making it harder to correlate them. That same year Adam Back detailed “bitcoins with homomorphic value”, which would eventually become the Confidential Transactions of Blockstream’s Elements Project. Back took a different tack by blinding the contents of a transaction, so that people outside the transaction could only see that it occurred (and what the mining fee was). The fact that later non-Confidential Transactions could leak information about previous Confidential Transactions is probably what led to the creation of fully privacy oriented blockchains, such as Monero in 2014 and Zcash in 2016, each of which took different approaches to secrecy.
Obviously, there is interest in increased blockchain privacy: it’s been one of the driving forces for cryptocurrency adoption. This transactional secrecy has a variety of advantages, the most crucial of which is fungibility: with true privacy, it becomes impossible to trace the provenance of an individual transaction, which is crucial for working currency; without it, the cryptocurrrency in individual transactions could be censored if the network did not like who used it or how it we used.
However, we must balance this growing philosophical desire for complete secrecy with the philosophies that have been a developed part of the blockchain from the start. Secrecy may actually enhance some of the blockchain’s core ideals, such as its censorship resistance. And, it doesn’t hurt others, such the blockchain’s trustlessness: protocols like Blockstream’s Confidential Transactions were explicitly designed to balance out the inputs and outputs of a transactions, allowing verification by anyone. But that’s not to say that secrecy doesn’t have problems of its own.
One of the original goals of Bitcoin (and other cryptocurrencies) was to give power back to the people. In the physical world, we’ve lost agency to corporations, government, and plutocrats. The blockchain gave that back to us in part due to its transparency. It suddenly became possible to require that transactions of public entities be public in a way that we never could have considered in traditional financial systems. We could require that proxies publicly reveal their votes, that elected officials detail their contributions, and that corporations declare transactions related to their advertisements, their guarantees, and their certifications — and many of these revelations could be verified through the blockchain itself.
But now, as a shroud of secrecy is spreading across blockchains, expectations of transparency are rapidly fading. If cryptocurrency becomes as opaque as traditional currency, then the opportunity to demand transparency, to truly change the rules of the game, will evaporate.
Confidential transactions and privacy-protecting digital currencies are being advertised as a way for us to have privacy, but it’s them, the rich and the powerful, who will make the greatest use of this power. We already see this in the opaque finances of the physical world, at places like Deutsche Bank, which is facing legal action as the result of laundering twenty billion dollars of Russian money. If the transparency of the blockchain becomes opaque, it’ll happen there too. The rich and the powerful will hide their transactions so that they can maintain the influence and authority they’ve gathered in the physical world and extend it to the digital world — using the very tool that’s supposed to reverse those trends.
In addition, secrecy may turn cryptocurrencies into what people fear. There has long been concern over criminal uses of the blockchain but the transparency and pseudonymity of most blockchains have worked against that — and in fact have made criminals vulnerable when they mistakenly thought they were safe. Cryptocurrrency secrecy could let them in.
Perhaps we, as a blockchain community, will assess these costs as acceptable given the privacy gains for the common person. Or perhaps not. But the problems become even greater when moving from cryptocurrency to the wider world of digital assets, a topic that’s dear to us at Bitmark.
Bitmark defines and defends digital property through the Bitmark Property System, which allows people to register their digital assets and data, then to license, sell, loan, or otherwise leverage that digital property for the good of both themselves and our society. KKBOX’s use of the Bitmark blockchain to record royalties for the use of digital music shows how this system can help individual musicians, while UC Berkeley and Pfizer have demonstrated the benefits of recording health data permissions to support health studies and clinical trials that could contribute to the whole world. But for digital assets to have value, it’s vitally important that ownership records be public, not secret.
Last year we wrote about the case of Shepard Fairey, whose famous “Hope” stencil portrait of Barack Obama became the source of a legal dispute because Fairey didn’t license the original photographic source. That case study demonstrates our need to know who owns something so that we can license it (or purchase it or borrow it): secrecy works against the interests of both asset holders and hopeful licensees. The music industry offers another use case: rights information should be stored in electronic data, but it’s often wrong, which has left artists unable to collect billions of dollars in royalties.
This problem of determining asset ownership is so large that it became a major focus of the US Copyright Office in the ’00s. As corporations like Google tried to turn physical assets into digital assets, they ran into a major problem with “orphan works”, where they couldn’t discover who the rights-holder for an asset was, and so were unable to attain permission (or refusal) to use the work. The Copyright Office was thus tasked with determining whether these orphaned works still served to “promote the progress of Science”, one of the major purposes for copyright in the United States. Their conclusion was:
Alt, Casey, Sean Moss-Pultz, Amy Whitaker, & Timothy Chen. November 2016. “Defining Property in the Digital Environment”. https://new.bitmark.com/files/bitmark_defining-property-dig-env.pdf.
Bitmark. Retrieved July 2019. “Why Property Rights Matter”. Bitmark. https://bitmark.com/en/property-blockchain/why-property-rights-matter.
Bitmark. October 2018. “How to Use the Blockchain to Riff Artwork, Sell PDFs, and Otherwise Gain Economic Control of Your…” Hackernoon. https://hackernoon.com/bitmark-how-to-use-the-blockchain-for-property-rights-ecf9f5e67e77.
Blockstream. Retrieved 2019. “Elements by Blockstream”. The Elements Project. https://elementsproject.org/.
Deahl, Dani. May 2019. “Metadata is the Biggest Little Problem Plaguing the Music Industry”. The Verge. https://www.theverge.com/2019/5/29/18531476/music-industry-song-royalties-metadata-credit-problems.
Hsiang-Yun L. February 2019. “Coase Theorem in the World of Data Breaches”. Human Rights at the Digital Age. https://techandrights.tech.blog/2019/02/22/coase-theorem-in-the-world-of-data-breaches/.
Maxwell, Greg. August 2013. “CoinJoin: Bitcoin Privacy for the Real World”. Bitcoin Talk. https://bitcointalk.org/index.php?topic=279249.0.
Nakamoto, Satoshi. October 2008. “Bitcoin: A Peer-to-Peer Electronic Cash System”. https://bitcoin.org/bitcoin.pdf.
Poelstra, Andrew, Adam Back, Mark Friedenbach, Gregory Maxwell, and Pieter Wuille. 2017. “Confidential Assets.” Blockstream. https://blockstream.com/bitcoin17-final41.pdf.
US Copyright Office. June 2015. “Orphan Works and Mass Digitization”. Copyright.gov. https://www.copyright.gov/orphan/reports/orphan-works2015.pdf.
Van Wirdum, Aaron. November 2015. “Is Bitcoin Anonymous? A Complete Beginner’s Guide”. Bitcoin Magazine. https://bitcoinmagazine.com/articles/is-bitcoin-anonymous-a-complete-beginner-s-guide-1447875283.
Van Wirdum, Aaron. June 2016. “Confidential Transactions: How Hiding Transaction Amounts Increases Bitcoin Privacy”. Bitcoin Magazine. https://bitcoinmagazine.com/articles/confidential-transactions-how-hiding-transaction-amounts-increases-bitcoin-privacy-1464892525.