Privacy Cash
A zero-knowledge shielded pool on Solana and four EVM chains that breaks the on-chain link between a deposit and a later withdrawal.
LiveShielded pool
Live on Solana since August 2025 and on Base, Ethereum, BNB Chain and Robinhood Chain since 2026; DefiLlama put total TVL at about $1.91 million on 16 October 2026.
- TVL
- $1.9MDefiLlama, 18 Oct 2026
- Launched
- Aug 2025
- Token
- None
- Chains
- Solana, Base, Ethereum, BNB Chain and Robinhood Chain
How it works
Privacy Cash is a shielded pool: a set of contracts that hold many users' deposits together, so that a later withdrawal cannot be traced back to the deposit that paid for it. It launched on Solana in August 2025 and added pools on Base, Ethereum, BNB Chain and Robinhood Chain during 2026. Auditors describe the design as an adaptation of Tornado Cash Nova, so deposits and withdrawals can be of any size within minimum and maximum limits set by the operators, rather than in fixed denominations. On Solana the pools hold SOL, USDC, USDT, ZEC, ORE, stORE, jlUSDC and jlWSOL; each EVM chain has a pool for its native coin and one for a stablecoin (USDC on Base, USDT on Ethereum and BNB Chain, USDG on Robinhood Chain).
When a user deposits, the app creates an encrypted note recording the amount and adds a fingerprint of it, called a commitment, to a Merkle tree stored on-chain. The key that encrypts the notes is derived by signing a fixed message with the user's wallet. To withdraw, the user's browser builds a Groth16 zero-knowledge proof that it owns an unspent note somewhere in the tree without revealing which one, and publishes a nullifier that stops the same note being spent twice. According to the documentation, a relayer signs and submits the withdrawal (on Solana it also pays the network fee), and the proof fixes the recipient and amount so the relayer cannot alter them.
Two further features build on the pool. Private swaps, available on Solana only, move funds from the pool into a temporary wallet, trade them through Jupiter and return the result to the pool. Private bridging withdraws funds to a cross-chain service, NEAR Intents or, from Robinhood Chain, the Relay network, which delivers them on another chain, so the sender seen on-chain is the pool rather than the user.
Privacy Cash hides the link between a deposit and a withdrawal, not the transactions themselves. Anyone can see which address deposited, how much and when, and which address received a withdrawal, how much and when. The documentation warns that withdrawing a distinctive amount soon after depositing it lets observers make an educated guess, and it advises users to vary amounts and timing. The relayer screens depositing wallets through CipherOwl and rejects those flagged as malicious, the terms of use reserve the right to log transaction metadata, and auditors note that the indexer which supplies Merkle proofs can see which note a user is about to spend. Because the keys come from a wallet signature, signing the same message on a phishing site could let an attacker read and spend a user's shielded balance.
TVL over time
- $1.9M TVL now
- -3.1% in 30 days
- $3.1M highest daily TVL, 22 Sep 2026
Daily total value locked (TVL) from DefiLlama since 29 Aug 2025, with the current value refreshed every hour. The latest value is from 18 Oct 2026, 04:12 UTC. The series is in protocol-privacy-cash.json, listed on the Data page.
What it hides and what it does not
What it hides
- Which deposit a withdrawal comes from: the proof shows that the user owns an unspent note somewhere in the pool, without revealing which one.
- The user as the sender of a private bridge transfer: the sender seen on-chain is the pool.
What it does not hide
- Which address deposited, how much and when.
- Which address received a withdrawal, how much and when.
- A distinctive amount withdrawn soon after it was deposited, which the documentation warns lets observers make an educated guess.
- Depositing wallets, to the relayer, which screens them through CipherOwl; the terms of use reserve the right to log transaction metadata.
- Which note a user is about to spend, to the indexer that supplies Merkle proofs, as auditors note.
Drawn from how it works, above; the sources are listed at the end of the page. Where privacy still leaks explains the patterns, such as timing and amounts, that can give users of any design away.
Audits
17 security reviews, oldest first, with what each covered and found. Dates are when each report was issued, unless the entry says otherwise.
| Date | Firm | Scope and findings |
|---|---|---|
| HashCloak | Solana program, Circom circuits and the web app's proving code, first delivered on 4 July 2025 and finalised on 9 August 2025. A critical double-spend flaw found after that delivery was first listed, as fixed, in the update of 1 September 2025 and later re-reviewed; versions up to 18 June 2026 cover USDC and other SPL token support. Sources: Code review and security assessment for ZKCash, final version of 9 August 2025 ; Code review and security assessment for ZKCash, updated version of 1 September 2025 ; Privacy Cash code review and security assessment, final version 4 ; Privacy Cash code review and security assessment, version 9 |
|
| Accretion | Solana program for private SOL transfers, reviewed from 27 June to 16 August 2025 (report A25PRC1). Two critical issues, one letting the tree authority lock funds and one allowing front-running and theft through missing recipient validation, were fixed. |
|
| Zigtur | TypeScript SDK for Solana (version 1.1). Findings on privacy leaks through RPC queries and through the indexer's Merkle proof service were acknowledged and not fixed. |
|
| Zigtur | Solana program and circuits at commit 5496860, plus two later commits (version 1.6). Seven informational findings; the review did not assess the trusted setup ceremony. |
|
| Not dated | Kriko | Solana program and circuit at commit 5496860, plus two later commits. Two informational findings. The report is undated; this version's PDF was generated on 28 October 2025, and an earlier version, generated on 10 September 2025, was in the repository from 24 September 2025. Sources: Privacy Cash security review ; Privacy Cash security review (earliest repository version) |
| Sherlock | Private best-efforts audit contest held from 13 to 17 November 2025 on the circuits, Solana program and encryption primitives, with the final commit being the merge that added USDC support. No high or medium issues were reported. Source: Security review for Privacy Cash: private best-efforts audit contest |
|
| Veridise | Solana program and circuits at commit 4b2ec49, reviewed from 10 to 14 November 2025 for SPL token support (report V3). A critical flaw that could have drained the pool was fixed before the change was merged, two warnings were acknowledged, and the Picus tool was used to prove the circuits deterministic. |
|
| Accretion | SPL token transfer feature of the Solana program, reviewed from 20 November to 8 December 2025 (report A25PRC2). One high-severity issue, which let users make the relayer pay token account costs, was marked won't fix. |
|
| Zigtur | USDC integration in the Solana program (version 1.1). A high-severity flaw that let SOL deposits be withdrawn as USDC was fixed by giving each token its own Merkle tree. Source: Privacy Cash USDC integration audit report, version 1.1 |
|
| Not dated | Kriko | Upgrade adding SPL tokens to the Solana program at commit 4b2ec49, with a mitigation review and a check of later token additions. A critical flaw that let users withdraw a different token from the one deposited was fixed. The report is undated; its PDF was generated on 18 December 2025. |
| Zigtur | Support for multiple SPL tokens in the Solana program and SDK (version 1.0), updated on 10 February 2026 (version 1.3) to cover stORE, jlUSDC and jlWSOL. One medium issue, a wrong ORE address in the SDK, was fixed. Sources: Privacy Cash MultiSPL audit report, version 1.0 ; Privacy Cash MultiSPL audit report, version 1.3 |
|
| Nethermind | EVM pool contracts (report NM-0853), including checks that the on-chain verifier matches the circuit and its trusted setup, which recorded four contributions, and that proofs are compatible between the Solana and EVM versions. Three informational findings. Source: Security review report NM-0853: Privacy Cash Core EVM |
|
| Not dated | Kriko | EVM contracts at commit 3a5acf7 and the USDC upgrade at commit 1e9af6a. Three low-severity gas-griefing issues were addressed in the contracts or the team's infrastructure, and the USDC review found no further issues. The reports are undated; their PDFs were generated on 16 March and 6 April 2026. Sources: Privacy Cash EVM security review ; Privacy Cash EVM security review (USDC upgrade) |
| HashCloak | EVM pool contracts and circuits for ETH on Base, finalised on 17 March 2026, with updated versions up to 21 August 2026 covering the USDC pool and deployments on Ethereum, BNB Chain and Robinhood Chain. One low and five informational findings. Sources: Privacy Cash Core EVM code review and security assessment, final version ; Privacy Cash Core EVM code review and security assessment, version 3.0 ; Privacy Cash Core EVM code review and security assessment, version 6.0 |
|
| Zigtur | EVM pool contracts (version 1.2), updated on 5 April 2026 (version 1.3) for the ERC-20 pool. Low and informational findings only, including bypassable fees and notes on the UUPS upgrade pattern. Sources: Privacy Cash Core EVM audit report, version 1.2 ; Privacy Cash Core EVM audit report, version 1.3 |
|
| Zigtur | EVM SDK (version 1.1). A medium issue that wrote UTXO private keys to a temporary file was fixed; a low issue on privacy leaks to, and reliance on, the centralised indexer was acknowledged. |
|
| HashCloak | EVM SDK, finalised on 29 April 2026 and updated on 26 May 2026 (version 2.0). Two low-severity findings, on deriving keys from a wallet signature and on trust in the centralised indexer, were both acknowledged and left unchanged. Sources: Privacy Cash SDK EVM code review and security assessment, final version ; Privacy Cash SDK EVM code review and security assessment, version 2.0 |
Incidents
One incident that affected the project or its users.
-
News reports, citing an on-chain analyst, said the proceeds of a theft of about $4 million from a crypto trader's wallets were swapped into ETH, BNB and SOL and then moved through Privacy Cash and Chainflip. No statement from Privacy Cash about screening or blocking the funds was reported.
Sources: Trader's wallet suspected of being hacked for about $4 million in crypto assets; hacker laundered funds via privacy tools ; Crypto trader Frogman hacked for over $4 million during TOKEN2049
Milestones
17 milestones, oldest first.
-
The Solana program was deployed on mainnet, and its upgrade authority was transferred the same day to a Squads multisig wallet.
Sources: Solana transaction 3SYDtthDLD83gDgSKAGLX3nLnhLmng1VeRTNNcrB4dNXqwYsNTUP35HBurwDx5xM4bCguMBQui8BmHGfPsd5uN44 deploying program 9fhQBbumKEFuXtMBDw8AaQyAjCorLGJQiS3skWZdQyQD (getTransaction) ; Solana transaction r23wKY9VQVB5NGUVm7shvSjHNLAtRZsaKs7Rdmu7r3MBpoaXhpGU5PtPb5F1Z2E3tiZ79anjX37PoC4xueJApiE setting the program's upgrade authority to AWexibGxNFKTa1b5R5MN4PJr9HWnWRwf8EW9g8cLx3dM (getTransaction) ; Squads multisig account AqoNsGV9ccPPe1bSJ1B3uA5BptehckWJ2qQouKY7CS5n, whose vault holds the upgrade authority: threshold 3 of 5 members, time lock 0 (getAccountInfo) ; Privacy-Cash/privacy-cash README
-
PANews, citing SolanaFloor, reported that Privacy Cash had launched on Solana for private SOL transfers and had already processed more than 10,000 SOL.
Source: Privacy Cash, the privacy payment project, is now available on Solana, supporting private transfers
-
HashCloak issued an updated report adding a critical double-spend flaw, found after its August delivery and recorded as fixed, and the Solana program was upgraded on-chain through the multisig the same day.
Sources: Code review and security assessment for ZKCash, updated version of 1 September 2025 ; Solana transaction 55xhXz6YM4i11QnSj12T4FgSyNfPBoFDyYaoD8DTyncxTCfQyqfnZ2oLKbY6dxrvdE7DHXeDsa566mm4SPU2tNdB upgrading program 9fhQBbumKEFuXtMBDw8AaQyAjCorLGJQiS3skWZdQyQD through a Squads multisig (getTransaction)
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The Privacy-Cash GitHub organisation created a repository for the Solana program and circuits, with an initial commit that day, followed by a TypeScript SDK repository on 28 September 2025.
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USDC support was merged into the Solana program, with a separate Merkle tree for each token.
Sources: Support USDC (pull request 7) ; Privacy Cash USDC integration audit report, version 1.1
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Step Finance's Solana Data Insights newsletter reported more than 680,000 SOL, about $121 million, in deposits and withdrawals over the protocol's first 100 days, from more than 11,700 wallets.
Source: Privacy Cash: Over $121M in Private Transfers During Its First 100 Days
-
USDT, ZEC and ORE pools were added to the Solana program.
Sources: add some new spl tokens (pull request 9) ; Privacy Cash code review and security assessment, version 9
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Support for stORE, a staked ORE token, was merged into the Solana program.
Sources: add stORE (#15) ; Privacy Cash code review and security assessment, version 9
-
SolanaFloor reported the launch of private swaps routed through Jupiter, a record 1,192 daily active wallets, more than $174 million in private transfers and TVL above $2.1 million; DefiLlama's series put TVL at about $0.94 million that day.
Sources: Privacy Cash Launches Swaps as Daily Addresses Hits All-Time High ; Privacy Cash protocol TVL
-
Support for jlUSDC and jlWSOL was merged into the Solana program.
Sources: Support jlUSDC and jlWSOL (#16) ; Privacy Cash code review and security assessment, version 9
-
The EVM version was first deployed on Base with an ETH pool; the pool was redeployed on 6 April 2026 and a Base USDC pool followed on 8 April 2026.
Sources: Base transaction creating the first Privacy Cash ETH pool proxy ; Privacy Cash Core EVM commit history ; Base transaction creating the Privacy Cash ETH pool proxy ; Base transaction creating the Privacy Cash USDC pool proxy
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An ETH pool was deployed on Ethereum mainnet, followed by a USDT pool on 19 May 2026.
Sources: Ethereum transaction creating the Privacy Cash ETH pool proxy ; Ethereum transaction creating the Privacy Cash USDT pool proxy ; Privacy Cash Core EVM code review and security assessment, version 3.0
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A reissued stORE token was added after a vulnerability in the ORE protocol's staking program; the legacy stORE pool was kept open for withdrawals.
Sources: add new stORE (pull request 17) ; Privacy Cash code review and security assessment, version 9
-
Pools for BNB and USDT were deployed on BNB Chain.
Sources: Privacy Cash Core EVM code review and security assessment, version 6.0 ; Privacy Cash Core EVM commit history
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An ETH pool was deployed on Robinhood Chain, followed by a USDG pool on 21 August 2026.
Sources: Robinhood Chain transaction creating the Privacy Cash ETH pool proxy ; Robinhood Chain transaction creating the Privacy Cash USDG pool proxy ; Privacy Cash Core EVM code review and security assessment, version 6.0
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TVL reached about $3.11 million, the highest daily value in DefiLlama's series, before easing to about $1.91 million by 16 October 2026.
Source: Privacy Cash protocol TVL
-
The documentation stated that more than $600 million had been privately transferred and swapped through the protocol.
Source: Privacy Cash user docs
Funding
One source of funding. Amounts are in US dollars; a dash means the sources give no US dollar figure.
| Date | Round | Amount | Investors |
|---|---|---|---|
| Not dated | Backing; amount, date and terms not disclosed Source: Privacy Cash user docs |
– | AllianceDAO |
Risks
Privacy depends on how many people use the same pool and how they use it. On 16 October 2026 DefiLlama put Privacy Cash's Solana pools at about $1.69 million and its EVM pools at about $215,000 combined, with under $10,000 each on BNB Chain and Robinhood Chain, so on the smaller pools a deposit and a withdrawal of similar size are easy to pair. Users also depend on services the team runs: CipherOwl screening is an off-chain policy of the relayer and the app rather than a contract rule, since the on-chain programs accept a valid proof from any sender; the indexer can link Merkle proof requests to spends, a weakness Zigtur and HashCloak reported and the team acknowledged, saying it does not log these requests and that anyone can run an indexer; and the terms of use reserve the right to log transaction metadata. The Solana program can be upgraded by a Squads multisig that needs three of its five members and has no time delay, and the EVM pools can be upgraded or paused by a Safe multisig that also needs three of five signers. The proofs are only sound if the Groth16 trusted setup was honest: Zigtur's October 2025 report did not assess the ceremony, and Nethermind's March 2026 review found four contributions recorded in the proving key, which is secure if at least one contributor destroyed their secret values. Audits found critical flaws, all recorded as fixed, and no exploitation has been reported; one, a double-spend bug, was first listed in HashCloak's update of 1 September 2025, after the Solana program had gone on-chain on 6 August 2025, and the program was upgraded that day, but no source says whether the deployed version was affected. In October 2026 stolen funds were reported to have passed through the protocol, and the documentation advises withdrawing to a fresh self-custody wallet before sending funds to exchanges, which may hold them for manual review.
Sources
The documents this profile rests on. Each audit, incident, milestone and funding round above also links its own sources.
- Privacy Cash
- Privacy Cash user docs
- Privacy tips
- FAQ (Solana SDK)
- Privacy Cash terms of use
- Privacy Cash relayer configuration
- Privacy-Cash/privacy-cash README
- zkcash Solana program source (lib.rs)
- Privacy-Cash/privacy-cash-core-evm README
- EtherPool.sol (admin-only pause and upgrade)
- privacy-cash-sdk-evm deposit.ts (address screening before deposit)
- Deployment and upgrade history of Solana program data account 863Rd7vyk2vGoME8rh7t92K5X4czFY4WDCS9LYwZbvsV (getSignaturesForAddress)
- Squads multisig account AqoNsGV9ccPPe1bSJ1B3uA5BptehckWJ2qQouKY7CS5n, whose vault holds the upgrade and admin authority: threshold 3 of 5 members, time lock 0 (getAccountInfo)
- Base address record for the Privacy Cash EVM admin 0x44eb9939cfdE7C394f1632C6890191d695f0a3ce (SafeProxy)
- Pool admin() and Safe getThreshold/getOwners on Base: admin is a 3-of-5 Safe (eth_call)
- Pool admin() and Safe getThreshold/getOwners on Ethereum: admin is a 3-of-5 Safe (eth_call)
- Pool admin() and Safe getThreshold/getOwners on BNB Chain: admin is a 3-of-5 Safe (eth_call)
- Pool admin() and Safe getThreshold/getOwners on Robinhood Chain: admin is a 3-of-5 Safe (eth_call)
- Alliance companies
- Privacy Cash protocol TVL
- Privacy Cash SDK audit report, version 1.1
- Privacy Cash audit report, version 1.6
- Privacy Cash Core EVM SDK audit report, version 1.1
- Privacy Cash SDK EVM code review and security assessment, version 2.0
- Security review report NM-0853: Privacy Cash Core EVM
- Code review and security assessment for ZKCash, updated version of 1 September 2025
- Privacy Cash code review and security assessment, final version 4
- Privacy Cash, the privacy payment project, is now available on Solana, supporting private transfers
- Privacy Cash: Over $121M in Private Transfers During Its First 100 Days
- Privacy Cash Launches Swaps as Daily Addresses Hits All-Time High
- Trader's wallet suspected of being hacked for about $4 million in crypto assets; hacker laundered funds via privacy tools
- Crypto trader Frogman hacked for over $4 million during TOKEN2049
