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Privacy has been a recurring theme in the cryptocurrency space for years. Just a few weeks after Bitcoin (BTC)’s launch, Hal Finney pointed out this issue in only his second tweet about Bitcoin (BTC), but the concept did not gain widespread attention until the arrival of Monero (XMR) in 2014. Since then, privacy has repeatedly re-emerged as a core promise of decentralized money, especially in moments of heightened concerns around regulatory pressure and financial oversight.
summary
Opt-in privacy destroys networks. If a user is required to turn privacy “on,” the anonymity set shrinks and private transactions become more visible. The problem is design, not demand. Although Zcash has a high level of encryption, most transactions remain transparent. The momentum of the story is not reflected in the usage. Privacy should work by default. Like security, financial privacy is only enhanced if everyone shares it. This is automatic, universal, and built into the protocol.
Analysts believe the future of cryptocurrencies will continue to be defined by the privacy narrative. Investor Balaji Srinivasan argued that privacy will define the industry for the next eight years. Meanwhile, a16z Crypto said that by 2026, privacy will be the most important “moat” in the industry. In fact, Privacy Coin rose at the end of 2025 and continues to fluctuate until the beginning of the new year. At its peak, the sector’s total market capitalization exceeded $40 billion, but has since fallen back to around $17 billion.
Zcash (ZEC) has been the main driver of its resurgence, rising more than 1,300% from late September 2025 to all-time highs, and remains up more than 600% at current prices, briefly overtaking Monero in total market volume. However, despite renewed interest and pricing momentum, actual privacy uptake remains shockingly low. Zcash’s shielded pool continues to hold just over 30% of the circulating supply, and approximately two-thirds of transactions are still fully visible on-chain.
This disconnect reveals a deeper problem. If privacy is a growing concern, why aren’t users moving to the very privacy layer designed for that purpose? The answer may be simply structural. Opt-in privacy is what makes encryption fail.
Opt-in privacy was a design compromise
In 2013, the pseudonym Nicolas van Saberhagen published the CryptoNote v2 paper. This paper clearly positions transaction privacy not as a “nice-to-have” but as a core requirement for electronic money. The paper argues that Bitcoin’s transparency allows for pseudo-anonymity at best, and outlines two characteristics that a true private payment system must meet: untraceability and unlinkability. Andrey Sabelnikov, now co-founder of Zano, worked with Nicolas to realize this vision and implement the protocol he designed. From the beginning, CryptoNote made privacy the default, built into every transaction rather than an afterthought.
However, as the industry evolved, many projects lost sight of this principle. Rather than pushing the boundaries of privacy-preserving technology, they chose the path of least resistance, prioritizing compatibility, performance, and mainstream appeal over user protection. Privacy-protecting encryption was still expensive and unfamiliar, so new designs retreated to an opt-in model.
This compromise had serious consequences. Privacy is now a feature you turn on, rather than a basic guarantee. Users who chose the private option effectively marked themselves as having something to hide, while the default transparent experience left them largely exposed. While this tradeoff may have seemed realistic at the time, it fundamentally betrayed the original vision established by CryptoNote. In other words, true electronic money needed to protect user privacy by design, not as an afterthought. It had to be designed into the core transaction model itself.
The largest network that inherits the original default privacy philosophy is Monero. Launched in 2014, it adapted the CryptoNote protocol while maintaining the principles already established by Nicolas and Andrey. Rather than asking users to choose between public and private modes, this design assumes that financial transactions should be private by default, improving privacy by having everyone share the same protections.
This philosophy makes privacy not just a feature, but a network effect. The strength of a privacy system is determined by the strength of the crowd it can hide from. When privacy is an option, the network is divided into transparent and private activities. No matter how sophisticated the encryption, the private pool becomes smaller, the anonymity set shrinks, and the privacy model actually weakens.
Zcash paradox
Zcash illustrates a central contradiction facing many of today’s privacy ecosystems. In theory, it offers some of the most advanced privacy techniques in cryptocurrencies, including zero-knowledge proofs that can fully protect the details of your transactions. However, in reality, the majority of network activity remains transparent.
Despite renewed market interest and strong price performance, Zcash’s shielded pool continues to hold just over 30% of the circulating supply, and approximately two-thirds of transactions are still fully visible on-chain. The technology exists. Our privacy guarantee is real. But most users don’t use them.
This gap is not a failure of encryption or a lack of privacy demands. This is a predictable result of an opt-in design. When privacy is presented as another mode that users must consciously enable, it creates friction, uncertainty, and reduced behavior. Many users choose transparent transactions by default simply because they are easier, faster, and more familiar. Some people may not know the difference at all.
The result is a fragmented network. Public and private transactions coexist, but they do not reinforce each other. Instead, the private pool remains small, limiting the size of the anonymity set and weakening privacy guarantees for users who opt in. Ironically, using privacy in an opt-in system makes users more visible rather than less visible.
Privacy only works by default
Privacy is not a behavior that users can definitely choose. It functions as a collective property. The more participants that share the same privacy guarantee, the stronger that guarantee becomes. When privacy is optional, the network is split into public and private activities, reducing the anonymity set and lessening protection for users who opt in. In reality, optional privacy often makes users more visible rather than less visible.
Repeated cycles of interest in privacy coins show that demand is not the problem. The design is. Systems that rely on users actively choosing their privacy have a hard time converting narrative momentum into actual adoption. If privacy is to be the defining moat of cryptocurrencies, it must be treated as the underlying infrastructure, not a feature toggle. Financial privacy works best when it’s automatic, universal, and secure by default.
