CoinClear

Firo (formerly Zcoin)

5.2/10

Research-driven privacy coin with novel Lelantus/Spark protocols — genuine cryptographic innovation but small and overshadowed by Monero and Zcash.

Updated: February 16, 2026AI Model: claude-4-opusVersion 1

Overview

Firo, originally launched as Zcoin in September 2016, is a privacy-focused cryptocurrency that has made significant contributions to privacy technology research. The project was the first to implement the Zerocoin protocol (proposed by Matthew Green, Ian Miers, and others at Johns Hopkins University) in a live cryptocurrency, and subsequently developed the Lelantus and Lelantus Spark privacy protocols — novel constructions that improve upon Zerocoin's limitations.

Rebranded from Zcoin to Firo in November 2020, the project positions itself as a research-driven privacy coin. The Lelantus Spark protocol (activated in 2024) enables fully private transactions with no trusted setup requirement, direct anonymous payments, and efficient proof sizes. This represents a meaningful cryptographic advancement that doesn't rely on the trusted setup ceremony that ZK-SNARK-based privacy coins (Zcash, Iron Fish) require.

Despite genuine technical contributions, Firo has remained a small-cap privacy coin with limited mainstream adoption. The market cap typically sits in the $50-150M range, well behind Monero and Zcash. The project's research output is respected in the cryptography community, but translating academic innovation into user adoption has proven challenging.

Privacy Technology

Lelantus Spark

Lelantus Spark is Firo's current privacy protocol, activated on mainnet in early 2024. Key features include:

  • No trusted setup: Unlike Groth16 ZK-SNARKs (used by Zcash and Iron Fish), Spark doesn't require a trusted setup ceremony. Security doesn't depend on ceremony participants behaving honestly.
  • Direct anonymous payments: Users can send to Spark addresses without the recipient needing to be online or having interacted with the network before.
  • Efficient proofs: Spark proofs are reasonably compact and verification is efficient, making the protocol practical for everyday use.
  • Full privacy: Sender, receiver, and amount are all hidden in Spark transactions.

Spark represents a genuine improvement over Firo's earlier protocols (Zerocoin, Sigma, Lelantus) and offers a competitive privacy feature set without the trusted setup assumption.

Protocol Evolution

Firo's privacy technology has evolved through multiple generations:

  1. Zerocoin (2016-2019): First implementation; large proof sizes, trusted setup required.
  2. Sigma (2019-2021): Removed trusted setup, smaller proof sizes, but limited anonymity set.
  3. Lelantus (2021-2024): Large anonymity sets, no trusted setup, but one-way privacy (sender hidden, receiver visible via one-time addresses).
  4. Lelantus Spark (2024-present): Full privacy for sender, receiver, and amount, no trusted setup.

Each iteration addressed limitations of the previous version, demonstrating sustained research commitment.

Research Contributions

Firo's team has published peer-reviewed academic papers on Lelantus and Spark at cryptography conferences. The research contributions are genuine and recognized by the academic community — Firo punches above its weight in terms of cryptographic innovation relative to its market cap.

Security

Consensus

Firo uses a hybrid PoW/masternode consensus model. Mining uses the FiroPoW algorithm (a ProgPoW variant), while masternodes (requiring 1,000 FIRO collateral) provide a second layer of network services including InstantSend for fast transaction confirmation. The hybrid model aims to combine PoW's computational security with masternode-based services.

Network Security

The network hashrate is modest relative to major PoW chains, creating a lower barrier to 51% attacks. The masternode quorum (ChainLocks) provides additional protection against reorg attacks — masternodes sign blocks to prevent chain reorganizations, even if an attacker has majority hashrate. This is an effective mitigation against 51% attacks.

Historical Exploits

Firo (as Zcoin) experienced a critical cryptographic vulnerability in 2017 where the Zerocoin implementation had a flaw allowing the creation of fake coins, resulting in approximately 370,000 FIRO being fraudulently minted. The vulnerability was discovered and patched, but it represents a significant historical security incident. Later protocol versions (Sigma, Lelantus, Spark) addressed the underlying issues.

Decentralization

Mining Accessibility

FiroPoW is designed to be GPU-mineable, maintaining some mining accessibility. However, the small network size means a relatively modest investment in hashrate could gain significant mining share.

Masternode Network

The masternode network provides governance and services. Running a masternode requires 1,000 FIRO collateral, which at current prices represents a moderate barrier to entry. Masternode counts are in the hundreds to low thousands, providing reasonable distribution for a project of this size.

Governance

Firo governance involves community funding through a block reward allocation to a community fund, with spending proposals voted on by masternodes. This provides a degree of decentralized governance, though masternode voting power is concentrated among larger holders.

Adoption

Market Position

Firo is a small-cap privacy coin, typically ranked 300-500 by market cap. Adoption is limited to a niche community of privacy advocates and Firo enthusiasts. The project is available on select exchanges but lacks the broad listing coverage of top-tier privacy coins.

Real-World Usage

Firo has seen limited real-world payment adoption. The most notable use case was adoption by the Thai Democrat Party for its primary election in 2018 (when the project was still Zcoin), demonstrating privacy technology for secure voting. Beyond isolated use cases, daily transaction volumes are modest.

Community

The Firo community is small but technically engaged, with particular strength in Southeast Asia (the development team is based in Malaysia/Thailand). The community's dedication to privacy principles and cryptographic research creates a loyal but limited user base.

Regulatory Risk

Privacy Coin Challenges

Firo faces the same regulatory headwinds as other privacy coins: exchange delistings, jurisdictional restrictions, and government hostility to private transactions. As a smaller privacy coin, Firo is more vulnerable to delistings — exchanges are less likely to maintain support for a small-cap privacy coin when larger ones (Monero) are already being delisted.

Compliance Features

Firo has discussed implementing optional view keys and compliance-friendly features, acknowledging that pure privacy without any transparency mechanism faces increasing regulatory obstacles. The balance between privacy ideals and regulatory pragmatism is an ongoing debate within the community.

Risk Factors

  • Small market cap: Limited liquidity and vulnerability to large price swings.
  • Adoption failure: Despite strong technology, Firo has not attracted meaningful user adoption.
  • Historical exploit: The 2017 Zerocoin vulnerability, while patched, remains a concerning precedent.
  • Exchange delisting risk: Small-cap privacy coins are first targets for regulatory delistings.
  • Competition: Monero, Zcash, and newer privacy projects (Iron Fish) compete with more resources.
  • Team size: Small development team creates key-person risk and limits development bandwidth.
  • Privacy coin headwinds: Regulatory environment increasingly hostile to all privacy coins.

Conclusion

Firo is a genuine privacy technology innovator that has contributed meaningful research to the field. The Lelantus Spark protocol represents competitive privacy technology with the advantage of no trusted setup requirement. The project's academic output and sustained cryptographic research are impressive for its size.

However, research excellence hasn't translated to market adoption. Firo remains a small-cap privacy coin with limited user base, modest transaction volumes, and the ever-present risk of exchange delistings. The 2017 exploit, while addressed, adds historical concern. In a privacy coin landscape dominated by Monero's network effects and brand recognition, Firo's technical superiority in specific areas isn't sufficient to overcome the adoption gap.

The 5.2 score reflects genuine cryptographic innovation tempered by small-scale adoption, historical security concerns, and the challenging regulatory environment for all privacy coins.

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