Zcash is PoW privacy money with a shrinking security budget

Zcash is still one of the few large-cap chains that takes base-layer financial privacy seriously while keeping the consensus design simple: Proof-of-Work, miner-secured, no staking yield story required. The protocol specification explicitly frames Zcash as bridging Bitcoin-style transparent payments with a shielded payment scheme secured by zk-SNARKs, and it uses the Equihash memory-hard PoW algorithm in an attempt to reduce mining centralization pressure.

That choice forces clarity about tokenomics. ZEC’s primary economic function is to buy chain security through block subsidies and fees paid to miners. Everything else sits downstream. Development funding matters. Privacy UX matters. But if the security budget decays faster than those pieces can drive fees, the chain’s threat model weakens in a way that no wallet feature can paper over. For a PoW contrast point, see our Conflux tokenomics.

ZEC, the native asset on Mainnet, is also the unit used to pay transaction fees and to account for the protocol-defined “funding streams” that redirect a portion of issuance away from miners and toward ecosystem funding, enforced at the consensus layer via coinbase transaction rules.

Monetary base: hard cap, slow start, and halving math that keeps biting miners

Zcash uses “zatoshi” as the smallest unit, with 1 ZEC = 10^8 zatoshi.

The protocol constant MAX_MONEY = 2.1 × 10^15 zatoshi. With the 10^8 conversion, that corresponds to a 21,000,000 ZEC monetary cap.

Issuance starts with a “slow start.” The consensus constant SlowStartInterval = 20,000 blocks, and the block subsidy formula linearly ramps in that period instead of immediately paying the steady-state subsidy.

After slow start, the “max” block subsidy constant is MaxBlockSubsidy = 1.25 × 10^9 zatoshi, which equals 12.5 ZEC.

Zcash also changed its block target spacing at the Blossom upgrade. Pre-Blossom target spacing is 150 seconds and post-Blossom is 75 seconds. Blossom was scheduled to activate “on or around” December 11, 2019 at block height 653,600, and the intent is described as cutting block times in half to about 75 seconds.

Halvings are height-based. The protocol defines PreBlossomHalvingInterval = 840,000 blocks, and it defines PostBlossomHalvingInterval as floor(PreBlossomHalvingInterval × (PreBlossomPoWTargetSpacing / PostBlossomPoWTargetSpacing)). With 150/75 = 2, that gives 1,680,000 blocks per post-Blossom halving interval.

Those heights are not trivia. Canopy, which coincided with the first block subsidy halving, activated on November 18, 2020 at block height 1,046,400. NU6, which coincided with the second block subsidy halving, activated on November 23, 2024 at block height 2,726,400.

Post-Blossom, the block subsidy formula divides by a “BlossomPoWTargetSpacingRatio” (150/75) and by 2^Halving(height). Ignoring floor rounding in zatoshi units, after the second halving (Halving(height)=2), the steady-state subsidy is:

12.5 ZEC / (2 × 2^2) = 12.5 / 8 = 1.5625 ZEC per block.

Circulating supply estimate pages currently show an estimated circulating supply of 16,585,070 ZEC and a max supply of 21,000,000 ZEC (data viewed on March 5, 2026).

Who gets new issuance: allocations across eras (and why miners should care)

Zcash’s “distribution” is mostly an issuance split problem, enforced in coinbase construction. The miner subsidy is defined as the block subsidy minus the Founders’ Reward minus the sum of active funding stream values. That means every dev-funding decision is also a security-budget decision.

Post-NU6.1, the “headline” split many people cite is 80% to miners and 20% to ecosystem funding (8% + 12%), but the only reason that statement is meaningful is because those funding stream windows are pinned to explicit block-height ranges and end heights.

Fees and fiscal flows: ZEC mostly pays miners, not the protocol

Zcash’s coinbase transaction exists to “collect and spend” miner subsidy and transaction fees. There is no native burn that reliably tightens supply. Fees are not a sink. They are a revenue line for miners.

Fee policy is also unusual compared to many L1s. Conventional fee policy defines a mechanism where the fee scales with “logical actions,” using parameters including marginal_fee = 5,000 zatoshis per logical action and grace_actions = 2, implying a minimum conventional fee of 10,000 zatoshis (0.0001 ZEC). It is important that this is framed as a wallet and node policy standard (“Wallets implementing this specification SHOULD…”), not a hard consensus rule.

From a security-budget maximalist lens, deterministic low fees are a double-edged design. They reduce UX friction and make costs predictable, but they also make it structurally harder to “grow into” a fee market that can replace declining issuance. For a broader framing, it helps to separate token economy components from the narratives people build on top of them.

Meanwhile, issuance redirection is explicitly engineered. The protocol defines the miner subsidy as:

MinerSubsidy(height) = BlockSubsidy(height) − FoundersReward(height) − Σ fs.Value(height).

That equation is the token economy. It is also the security budget equation. If you want a quick mental model for the post-second-halving environment, combine it with the computed steady-state block subsidy of 1.5625 ZEC. With 20% diverted under active funding streams, miners’ share from subsidy is about 1.25 ZEC per block before fees (80% of 1.5625).

Governance and parameter control: ZIPs, upgrade windows, and funding as consensus

Zcash governance is mostly “parameter governance.” The key levers that change token flows are expressed as Zcash Improvement Proposals (ZIPs) and deployed via network upgrades at specific activation heights. The protocol specification describes network upgrades as “bilateral consensus rule change[s]” with an activation block height.

You can see this in the funding machinery itself. Consensus rules require coinbase outputs for active funding streams, and later governance pins concrete funding streams, recipients, and height ranges across revisions.

NU6.1 is the clearest example of “tokenomics as governance.” The NU6.1 activation is stated as block height 3,146,400 on November 24, 2025. That upgrade is tied to the transition into the Community and Coinholder Funding Model, including an explicit coinholder vote participation threshold: a minimum of 420,000 ZEC must be voted on a grant proposal for approval.

That same model also defines a veto process exercised by “Key-Holder Organizations,” where a grant is vetoed if any key-holder organization asserts legal/reporting issues, or if two or more assert principled objections based on user harm or misalignment with community values. This is a governance choice with tokenomic consequences. It reduces the risk of catastrophic grants. It increases the risk of deadlock. It also embeds real-world jurisdiction and institutional continuity into a mechanism that many participants will casually describe as “coinholder-controlled.”

Security-budget stress test: ranked risks for ZEC’s token economy

Top 3 risks

  1. Security budget compression (dominant), Trigger: block subsidy halvings continue while on-chain fee revenue remains low and predictable under prevailing fee norms. Mechanism: miner revenue falls, hashpower declines, and the cost to attack the chain drops; funding streams further reduce miner subsidy by design. Who bears it: ZEC holders and users (finality risk), exchanges and merchants (reorg risk), and miners (profitability shock). Measurable indicators: miner revenue per day (subsidy + fees), hash rate trend, fee share of miner revenue, and sustained mining concentration metrics.
  2. Governance deadlock or capture around the Coinholder-Controlled Fund, Trigger: low coinholder participation relative to thresholds, contentious grant proposals, or key-holder organizations exercising veto power. Mechanism: under-spending (ecosystem stagnation) or politicized spending (misallocation), coupled with delayed parameter evolution because funding is upstream of engineering capacity. Who bears it: builders (funding uncertainty), users (slower upgrades), and miners/holders (long-run competitiveness hit). Measurable indicators: coinholder vote participation vs the 420,000 ZEC minimum, veto frequency, grant throughput, and unspent balances in the coinholder-controlled pool.
  3. Regulatory and liquidity shocks that reduce fee demand, Trigger: exchange delistings, wallet support gaps, or compliance pressure on privacy assets. Mechanism: lower transactional usage reduces fee revenue and weakens the “fees replace subsidy” pathway, forcing the chain to live even more on issuance while issuance is already falling. Who bears it: holders (liquidity and volatility), users (access risk), and miners (revenue risk). Measurable indicators: exchange support coverage, transaction count and value transferred, and sustained declines in fee totals per block.

Dominant risk: security budget compression

Zcash’s tokenomics are security-budget constrained in a way that many PoS networks have not had to confront. There is no staking yield dial to turn. There is only miner revenue. Miner revenue is a function of (1) the block subsidy and (2) fees. For a PoS-style reference point, see our Gnosis tokenomics review.

Start with the mechanical slope. Post-second-halving, the steady-state block subsidy computes to 1.5625 ZEC per block. Under active funding streams, 20% is diverted (8% + 12%) and 80% remains available to miners as “miner subsidy,” before fees. That implies about 1.25 ZEC per block from subsidy to miners, plus fees. If fee revenue stays near the prevailing minimum for many transactions, fees are not structurally positioned to be the replacement leg.

Then look at the next step function. The 8% and 12% streams end at height 4,406,400, which is treated as the “3rd halving” boundary for this funding model. At that boundary, the subsidy halves again in the Bitcoin-like schedule. Under the same formula, the subsidy would move from 1.5625 to 0.78125 ZEC per block (again, ignoring floor rounding). If the funding split remains 80/20 at that time, miners’ subsidy share would compress toward 0.625 ZEC per block (80% of 0.78125), plus fees.

This is why I treat “lower inflation” narratives as secondary. In PoW, lower inflation without fee replacement is a direct reduction in the budget available to pay for honest work. The optimistic counterargument is that price can rise enough that miners stay paid in fiat terms even as ZEC issuance falls. That can happen. It is also not a security model. It is a market hope.

Zcash does have a credible reason to keep fees predictable and relatively low. It reduces UX failure modes. It also discourages bidding wars that can leak behavioral patterns. The conventional fee policy even sets requirements that the fee should not discriminate among pools and should avoid penalizing padding used to reduce leakage. Those are defensible privacy engineering goals.

But the security-budget trade-off remains. If blocks are rarely full, a fee market does not naturally emerge. If a fee market does not emerge, miners mostly live on subsidy. If miners mostly live on subsidy, every halving is a security budget halving in real terms unless demand grows fast enough to lift fee totals and price fast enough to lift fiat revenue.

There is a second-order effect that makes this sharper for Zcash than for a “pure miner-pay” chain. Zcash deliberately routes a meaningful slice of issuance away from miners for ecosystem work. The Canopy-era Dev Fund streams (7%/5%/8%) were explicitly designed to balance mining incentives against development needs. The problem is that this balance gets harder as absolute issuance shrinks. A fixed percentage becomes a smaller absolute amount for builders. Miners still lose the same percentage of their declining subsidy. Both sides feel squeezed. Network security is the side that cannot be backfilled quickly if it breaks.

NU6.1 also highlights how governance can interfere with security indirectly. A one-time lockbox disbursement of 78,750 ZEC to a specified multisig-related address structure was used to seed the coinholder model. That is a real capital movement. It helps fund development and governance experiments. It does nothing for miners. If this capital deployment fails to translate into higher usage and higher fees, it is, from a security budget perspective, simply a transfer away from the security line item.

A final point that often gets missed: “security budget” is not only about the aggregate. It is about distribution of who mines. If falling revenue pushes out smaller miners and concentrates hashpower, the chain’s attack surface can worsen even if total hashpower does not collapse immediately. Zcash’s use of Equihash is explicitly linked to mining-centralization concerns. The tokenomics need to be evaluated against that objective, not just against a simplistic “emissions go down” scorecard.

If you are building models or advising a project that needs to reason about these trade-offs, this is the kind of work where tokenomics consulting has to be security-budget-led, not narrative-led. The numbers are easy to quote. The incentive gradients are the hard part. If you want to go deeper on the measurement side, our research coverage tracks the same kinds of metrics used in these stress tests.



This article is part of our Tokenomics Deep Dive series.