CEO StarkWare Eli Ben-Sasson, one of the scientists behind the creation of Zcash, this week questioned one of bitcoin’s core principles — the 21 million coin cap.
In his view, the problem is lost private keys. The more BTC that remains permanently inaccessible, the smaller the real supply of usable coins becomes. That’s why Ben-Sasson believes that instead of a fixed cap, a different approach should be used — limiting the annual issuance of new BTC at 4%.
The reaction was swift. For bitcoin supporters, the 21 million cap is not just a technical detail, but one of the network’s fundamental promises. In response, Zcash founder Zooko Wilcox proposed another option that preserves the hard cap.
Maximum bitcoin supply. Source: CoinMarketCap
Why Ben-Sasson Disputes the 21 Million BTC Cap
Eli Ben-Sasson is well known in the crypto industry. He helped create the STARK proof system, which is now used in many blockchain projects. He was also one of the authors of Zerocash — the 2014 protocol that later became the basis for Zcash.
His argument centers on a simple problem: some bitcoins are already lost forever.
According to Chainalysis, as early as 2017, between 2.78 and 3.79 million BTC could have become inaccessible. These estimates usually include Satoshi Nakamoto’s coins, which have remained unmoved for many years. Meanwhile, there are still legal battles over old bitcoin wallets — assets worth about $235 billion are at stake.
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Ben-Sasson believes that limiting bitcoin’s supply to 21 million coins will eventually work against the network. If private keys continue to be lost, the amount of available BTC will keep shrinking. In the extreme scenario, he says, all keys could eventually be lost.
He is not against a clear monetary policy. On the contrary, Ben-Sasson says bitcoin should have a strict upper limit on new coin issuance. But he believes this limit is better set not by total BTC supply, but by maximum annual issuance.
As a benchmark, he suggested 4% per year. According to him, this is roughly in line with population growth. Another argument is miners. After 2140, bitcoin will stop issuing new coins, and miners will only receive fees. About 95.5% of all BTC has already been mined, so the issue of future incentives is becoming more prominent.
The situation is further complicated by the fact that network fees are currently near 2019 lows. This brings the market back to an old debate: will bitcoin be able to pay for its own security in the future solely through transaction fees?
Zcash Proposes Coin Burning Instead of New Issuance
Zooko Wilcox responded to Ben-Sasson, pointing to the Network Sustainability Mechanism from Shielded Labs. The idea is that ZEC holders can voluntarily burn their coins. The network then gradually recreates the same amount of coins and directs them as rewards to miners.
The main difference is that the total Zcash cap does not change. The maximum supply remains at 21 million ZEC.
But Ben-Sasson was not convinced by this option. According to calculations, the mechanism assumes burning 60% of network fees, which is about 210 ZEC per year. He believes these amounts are not enough to seriously support miners. So he returned to his main point: it’s more reasonable to limit inflation than to rigidly fix the total supply.
Other projects have faced a similar choice. Monero in 2022 chose the path of constant small issuance and added a reward of 0.6 XMR per block. This way, the network kept incentives for miners even after the main issuance ended.
Similar ideas have been raised in bitcoin more than once, but each time they have met strong resistance. For many BTC developers and holders, changing the cap is a red line.
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Meanwhile, the Zcash ecosystem is discussing another problem — hidden inflation. Cryptographer Sean Bowe, who worked on major privacy upgrades for Zcash, is now working on a proof system within Tachyon. It should demonstrate that the new Ironwood pool has no hidden bug that would allow extra coins to be created unnoticed.
Bitcoin supporters are not ready to reconsider their position. Their logic is simple: bitcoin’s strength lies in its unchanging basic rules. Michael Saylor has repeatedly promoted a similar idea, calling immutability one of the network’s main advantages.
Ben-Sasson’s proposal has almost no chance of being accepted. But the debate itself is important. It once again raised the question the bitcoin community cannot avoid: will fees alone be enough to secure the network after new BTC stop appearing?
For now, this debate remains mostly theoretical. There are still more than a hundred years until bitcoin’s issuance ends, so no one is planning to change the network rules now. Nevertheless, the discussion shows that developers are already thinking about how bitcoin will work in the distant future. Even if proposals like Ben-Sasson’s idea do not gain support, questions about the network’s long-term economics and miner incentives will likely come up more and more often.
