Atomic DvP Settlement

An asset manager sells a EUR 1M corporate bond position to a bank on an L2 network. Both parties want assurance that the bond and the EURC payment exchange atomically: either both legs settle or neither does, with deterministic recovery if a leg fails. The same primitive must serve derivatives margin and termination flows.

Atomic DvP via ERC-7573 (cross-network)

Enable atomic Delivery-versus-Payment across two networks so that either the asset is delivered and payment is completed, or the asset returns to the seller. The pattern targets institutions that need cross-network settlement with predictable failure behavior, auditability, and optional privacy extensions layered on top.

Attestation verifiable on-chain

Let smart contracts verify claims about an identity or off-chain fact without the contract or the public learning the underlying data. Trusted issuers sign attestations off-chain; verifiers check issuer signatures and revocation state on-chain and gate access on the result.

Aztec Rollup

Aztec is a privacy focused rollup (or zk-zk-rollup) on Ethereum that enables private transactions and programmable privacy. It is a fully programmable network where applications can access both private and public state.

Chainlink ACE

Modular compliance layer built on the Chainlink Runtime Environment (CRE) to define, execute, and enforce identity- and policy-based controls for digital assets across public and private chains. Core onchain components (CCID, CCT Compliance Extension) pair with CRE services (Policy/Identity/Monitoring managers). Offchain policy execution returns signed approvals; onchain enforcement is required. PII/NPI remains offchain. It enables private transactions, with one of the main target use cases being CBDCs management.

China (CN)

China maintains one of the world's strictest stances on cryptocurrencies, with comprehensive bans on cryptocurrency trading, mining, and payment services since 2021. All cryptocurrency transactions and related business activities are considered illegal financial activities. Despite the ban on decentralized cryptocurrencies, China actively develops its state-controlled CBDC (e-CNY/Digital Yuan) and promotes blockchain technology for enterprise and government applications through its "Blockchain Service Network" (BSN).

Commit-and-Prove Fallback

Coordinate a cross-chain settlement by having both parties post commitments to a shared secret witness `C = Com(w)`. Each leg of the trade references `C`, so auditors can link the two legs after the fact and each chain can verify its side against the same binding commitment. Atomicity is conditional: both legs settle independently, but neither can claim to have settled against a different commitment than the other.

Compliance Monitoring

Enable institutions to screen private transactions for regulatory compliance (AML, sanctions, fraud) without exposing transaction details to unauthorized parties. Balance privacy preservation with auditability through selective screening approaches and tiered disclosure, so settlement can proceed under compliance controls while counterparty identities and amounts remain shielded from public view.

Cross-Chain Privacy Bridge

Move assets between chains while preserving privacy on the destination by minting shielded notes whose ownership is not linkable to the source-domain depositor. Full sender and amount privacy requires privacy primitives on the source chain or pre-bridge anonymization; without these, the source lock transaction reveals the depositor address and amount.

Crypto-register bridge (eWpG) with EAS mirroring

Operate with a licensed crypto-register today while mirroring key legal facts (issuance, transfers, liens) as on-chain attestations. The registrar remains the legal source of truth; the on-chain anchor provides tamper evidence and paves the way for later automation once regulation allows.

Curvy

Curvy is a smart-contract-/wallet-based privacy layer for ERC-20 transfers (and other tokens) on EVM chains. It introduces **stealth addresses**, **view keys**, and **one-time addresses per transaction** to break linkability of sender-recipient pairs, while preserving usability.

DE / eWpG (Electronic Securities Act)

Germany’s **eWpG** lets you issue **electronic securities** (including **crypto-securities**) with legal equivalence to paper certificates, recorded either in a **central electronic register** or a **crypto-securities register**. Operating the crypto register and providing crypto custody are **regulated BaFin activities**.

Delegated Proving (co-SNARKs)

Offload zero-knowledge proof generation to a distributed prover network without revealing the witness. The user secret-shares their witness across several proving nodes; the nodes jointly run an MPC protocol to compute a single SNARK proof; no individual node ever reconstructs the full witness. The resulting proof is identical to one produced client-side and is verified on-chain or off-chain with no changes on the verifier side.

EIL (Ethereum Interoperability Layer)

Account-based cross-L2 interoperability where users sign once and execute transactions directly on multiple chains. Crosschain Liquidity Providers supply gas and liquidity via optimistic atomic swaps anchored in an L1 staking contract, but never execute calls on the user's behalf. Dispute resolution on L1 ensures funds cannot be lost or stolen.

ERC-3643 Tokenized RWAs

Enable compliant tokenization of real-world assets with built-in identity management, transfer restrictions, and regulatory rules enforced at the smart-contract level. Each transfer is gated by an on-chain identity check and a configurable compliance module before the underlying transfer executes.

EU / MiCA

The EU provides a **single passport** under **MiCA** for **Crypto-Asset Service Provider (CASPs)** and **token issuers** with detailed, prescriptive rules. Stablecoins (**Asset-Referenced Tokens (ARTs)/E-Money Tokens (EMTs)**) were the **first phase** (mid-2024); **CASP** obligations (authorisation, conduct, prudential, governance) apply from **2024-12-30**. Expect **strict AML “travel rule”** enforcement and **DORA**-grade operational resilience for in-scope entities.

EU Data Protection & Privacy-Enhancing Technologies

The EU's General Data Protection Regulation (GDPR) and Digital Operational Resilience Act (DORA) establish data protection obligations that apply to crypto entities alongside MiCA requirements. While MiCA regulates crypto-asset service providers, GDPR governs personal data processing, and DORA addresses ICT resilience and incident reporting. This card highlights the intersection of these frameworks and emerging privacy-enhancing technology discussions.

EY

A production-ready Zero-Knowledge rollup for private token transfers with enterprise compliance features. Nightfall v4 implements a ZK rollup that provides immediate finality and supports ERC20, ERC721, ERC1155, and ERC3525 tokens with X509 certificate-based access control.

Fairblock

Fairblock provides confidential balances and transfers for assets (e.g., stablecoins) that remain issued and liquid on an originating chain (e.g., EVM networks), while confidentiality logic executes on **FairyRing**, a purpose-built confidentiality execution layer.

Fireblocks

Fireblocks is a custody and infrastructure platform that provides secure wallet management and transaction workflows for institutions. In addition to custody and settlement rails, Fireblocks supports tokenization workflows, including issuing and managing tokenized bonds and other real-world assets for banks and asset managers.

Flashbots

Flashbots develops **MEV infrastructure** including private mempools, block building, and **SUAVE** (Single Unifying Auction for Value Expression) - a decentralized platform for private intent expression and execution.

FOCIL - Fork-Choice Enforced Inclusion Lists

Prevent censorship of Ethereum transactions by sophisticated block builders. A committee of 16 validators per slot can force-include transactions in the next block; non-compliant blocks fail fork-choice and cannot reach finality. The pattern provides no privacy on its own: transactions remain fully visible in the mempool and on chain. It guarantees only that a transaction cannot be censored once it reaches the public mempool.

Forced Withdrawal (L1 Escape Hatch)

When an L2 sequencer, relayer, or operator becomes unavailable, users need a unilateral path back to L1. Three pillars must hold simultaneously: the user has enough data to reconstruct their position, an L1 contract accepts proof of that position and releases funds, and the user can build the required proof on hardware they control. If any one leg fails, the escape hatch is ineffective.

Forward-Secure Signatures

Evolve a signing key over time so a signature produced under epoch `i`'s key remains verifiable later, but compromise at epoch `i+k` reveals only `epochSecret_{i+k}` and future epoch secrets. Past epoch secrets, and the privacy properties of past signatures (unlinkable nullifiers, addresses), remain protected.

Hinkal

Hinkal is a smart contract on public chains that lets users hold private balances controlled through their existing wallet keys. This enables users to send, receive and operate in stablecoins confidentially, without changing chains or custody. Through zero-knowledge proofs, every transaction is proven valid and verifiable on public chains, while participants and amounts stay private. Via viewing keys, users can selectively disclose transaction history to preserve auditability. And for compliance, Chainalysis KYT screens wallet addresses before execution to prevent high-risk funds from entering the smart contract.

Hong Kong SAR (HK)

Hong Kong operates under the "One Country, Two Systems" framework, maintaining a separate and progressive cryptocurrency regulatory system distinct from mainland China's complete ban. Since 2023, Hong Kong has established a comprehensive licensing regime allowing retail cryptocurrency trading, professional asset management, and institutional custody services. The Securities and Futures Commission (SFC) provides clear pathways for compliance, positioning Hong Kong as a major crypto hub for Asia-Pacific institutional activity.

Hybrid Public-Private Modes

Allow institutions to select public or private execution mode on a per-transaction or per-counterparty basis, optimizing for cost, latency, and confidentiality requirements. This enables hybrid workflows where some legs execute transparently on public infrastructure while others use privacy-preserving mechanisms, with atomic cross-mode settlement.

Hybrid TEE + ZK settlement

Coordinate private settlement inside a Trusted Execution Environment while anchoring correctness with a zero-knowledge proof verified on-chain. The enclave acts as a neutral synchronization layer between parties who do not trust each other: it matches orders, manages escrow state, and produces a succinct proof of correct execution. External observers see only commitments, proofs, and stealth-address outputs, while the enclave operator sees plaintext under contractual terms.

ICMA Bond Data Taxonomy (canonical terms/events)

Use the ICMA Bond Data Taxonomy as the canonical schema for bond terms and lifecycle events. A shared data model avoids fragmentation across issuance platforms, registrars, and regulators, and provides a stable foundation for attestations and zero-knowledge proofs over bond data.

iExec

iExec provides privacy-preserving computation, data governance, and trusted execution for decentralized applications through a decentralized network of **Trusted Execution Environments (TEEs)**.

Jurisdictional Focus: Banking Secrecy (Operating Constraints)

L2 Privacy Evaluation Framework

Give institutions a vendor-neutral, sourced methodology for comparing privacy-preserving L2 solutions across performance and cost, privacy and Data Availability, and security and governance. The framework defines a common workload so that self-reported metrics can be placed next to independent benchmarks on the same axes.

Lean Ethereum

Plan a long-range redesign of the Ethereum consensus layer, targeting a single major fork around 2030 that consolidates several research tracks: post-quantum signatures, minimal zkVMs for signature aggregation and proof compression, reduced hardware and stake thresholds for validators, and networking upgrades that support a larger validator set. The goal is a consensus protocol that is stable for decades, resilient against quantum adversaries, and verifiable on minimal devices.

Low-cost L2 + Off-chain Encrypted Audit Log

Run settlement on a low-cost L2, publish only commitments and hashes on chain, and keep the full transaction facts in an append-only encrypted log off chain. Integrity is anchored by periodic Merkle roots submitted on chain. Regulators and auditors receive scoped decryption keys or predicate proofs. Delivery-versus-payment is expressed through an atomic settlement standard.

Mesh Store-and-Forward Submission

Carry encrypted application payloads from an offline or intermittently-connected sender to an online relay over a delay-tolerant mesh network, with end-to-end confidentiality (intermediate peers see only ciphertext) and source-fingerprinting resistance at the radio and network layers.

Mixnet Anonymity

Hide who is sending a transaction or querying state by routing messages through a network of mix nodes that batch, delay, reorder, and pad traffic with cover messages. Mixnets provide stronger sender anonymity than onion routing against global passive adversaries because timing correlation is defeated by design, at the cost of higher latency and bandwidth overhead.

Modular Privacy Stack

Compose a privacy architecture from four distinct layers: Data, Execution, Settlement, and Disclosure. Each layer is addressed by an interchangeable technology so that institutions can select the best-fit primitive per layer, upgrade layers independently, and keep interoperability through standardized interfaces.

MPC Custody and Transaction Control

Provide custody and controlled execution of digital-asset transactions by distributing key shares across a set of signers that jointly produce a valid signature without ever reconstructing the private key. The pattern eliminates single points of key compromise and enforces policy-based approvals before any signature is released.

Native Account Abstraction (EIP-8141)

Make every Ethereum account natively programmable by replacing the hardcoded ECDSA `ecrecover` check with user-defined validation logic at the protocol level. Transactions are processed through the regular mempool using transaction frames that separate validation from execution. The design removes bundler and relayer dependencies, enables native gas sponsorship, and unlocks privacy patterns that currently require trusted off-protocol infrastructure.

Network-Level Anonymity

Hide who is sending transactions or querying state at the network layer. Content-privacy patterns (ZK, FHE, MPC) hide what is in a transaction but not who submitted it: IP addresses, timing, and query patterns still leak sender identity. Network-level anonymity complements content privacy to close the metadata gap.

Noir Private Contracts

Give developers a privacy-focused DSL to write smart contracts that blend public logic with confidential private computation in the same contract. Private functions execute client-side and produce zero-knowledge proofs; public functions execute on the sequencer transparently. Private and public state can be composed in a single application.

Onion Routing

Hide who is sending transactions or querying state by routing traffic through a chain of relay nodes. Each relay peels one layer of encryption, so no single relay sees both the sender's IP and the destination. Onion routing closes the metadata gap left by content-privacy patterns, which hide what is in a transaction but not who submitted it.

Open Intent Framework (OIF)

Enable cross-chain intent-based settlement where users express desired outcomes and permissionless solvers compete to execute them across chains. The framework separates user intent (what) from execution strategy (how) and plugs into external settlement, oracle, and messaging layers.

Origin-Locked Cross-Chain Confidential Ledger

Provide confidential balances and transfers for an existing ERC-20 on an origin EVM chain, while keeping the asset locked and settled on the origin chain. Confidentiality logic runs on a separate execution layer that maintains an encrypted ledger and verifies ZK-proven state transitions. Unlike a privacy bridge or a privacy rollup, funds never leave the origin chain.

Orion Finance

Orion Finance enables **private, onchain portfolio management** by integrating **confidential smart contracts** powered by advanced cryptography (FHEVM). Managers can run **encrypted strategies**, protecting their alpha while keeping results auditable and verifiable onchain. The architecture preserves DeFi’s **composability and transparency** for users while adding **institutional-grade confidentiality** for asset managers.

Paladin

Open-source (Apache-2.0) privacy layer under the [Linux Foundation Decentralized Trust](https://github.com/LFDT-Paladin/paladin). Paladin provides the common wallet/vault functions that are needed to interact with all forms of privacy preserving smart contracts. It also provides a model for atomic programmability across these privacy preserving smart contracts, harnessing the power of the underlying EVM shared ledger.

Peer

Peer (ex-ZKP2P) is an open-source protocol that enables peer-to-peer fiat-to-crypto swaps by proving fiat payments were completed on instant payment rails (Venmo, Revolut, and others). V3 uses a modular verification architecture: a TEE attestation service validates zk-TLS proofs offchain and emits EIP-712 payment attestations, which a Unified Payment Verifier contract checks onchain before releasing escrowed crypto.

Permissioned Ledger Interoperability

Enable atomic transactions and data exchange across distinct permissioned ledgers, so that institutions can interoperate without exposing all contract state or migrating to a single ledger. Each domain keeps its own consensus and governance; a coordination protocol synchronizes commits across domains.

Permissionless Spend Auth

Separate note ownership from spend authorization in a shielded pool, and use a recursive inner-outer circuit architecture so that multiple auth methods can coexist without fragmenting the anonymity set. Users can rotate or add auth methods without moving funds, and observers cannot tell which method authorized a given spend.

Pre-trade Privacy (Encrypted Order Flow)

Prevent front-running and information leakage by routing quotes and orders via encrypted or private submission paths so intent, size, and price stay hidden until inclusion. Settlement then proceeds on a shielded pool or confidential rail so the executed amounts also remain private.

Privacy L2s

Use a privacy-native rollup, either ZK-based or FHE-based, to execute financial logic with private state. This enables confidential value and unlinkable identity flows in a programmable environment, while anchoring security on Ethereum L1 via a bridge.

Privacy Pools

Privacy Pools is a smart contract protocol that extends the mixer model by allowing users to prove that their withdrawals come from (or do not come from) deposits belonging to a specific **association set**. Instead of merely unlinking deposits and withdrawals, users can provide **membership** or **exclusion** proofs, enabling them to disassociate from illicit deposits while retaining privacy within compliant sets.

Private Bond Issuance & Trading

A bank issues a EUR 100M corporate bond series with private allocation amounts to 50 institutional investors and operates an active secondary market with RFQ-based price discovery. The bank needs hidden positions and trade sizes, atomic same-chain DvP against EURC, jurisdiction-specific selective disclosure (eWpG, MiCA), and an automated 24/7 market with daily settlement.

Private Bonds

Institutional bond issuance and trading on public blockchains where volumes, prices, and positions must remain confidential to prevent front-running and strategy exposure. The solution requires confidential amounts and positions with selective regulator visibility, atomic delivery-versus-payment (DvP) settlement, while maintaining public-chain finality and economically viable daily settlement cycles.

Private Client Authentication for Institutional EOAs

Authenticate client externally-owned accounts in a way that satisfies regulatory KYC/AML requirements while preserving on-chain privacy. The institution maintains a Merkle tree of approved client EOAs; clients prove inclusion with a zero-knowledge proof plus a nullifier. Observers see neither the client's identity nor links between the client's other EOAs.

Private Commodities

Tokenized commodity trading where position sizes, trading strategies, and physical delivery arrangements must remain confidential. Gold is the primary tokenized commodity today, typically using synthetic/digital twin models. Trading houses require privacy to protect proprietary strategies and prevent market manipulation through position exposure.

Private Corporate Bonds

Corporate debt issuance where companies raising capital need to hide financing activity from competitors, employees, and market observers. Unlike public/government bonds, corporate bond issuance reveals strategic information about funding needs and potential credit stress.

Private FX

Cross-border foreign exchange settlement on blockchain where trading intent, positions, and execution details must remain confidential. FX is one of the largest financial markets; 99% of stablecoins are USD-backed, making cross-currency settlement a natural blockchain application. Institutions require privacy to prevent front-running and protect trading strategies.

Private Government Debt

Sovereign and municipal bond tokenization where the debt itself is public record but auction processes, holder positions, and trading activity may require privacy. Government debt differs fundamentally from corporate bonds: the existence and terms are typically public, but participant-level details need protection.

Private Identity

Prove identity claims, membership, eligibility, or attribute possession on-chain without revealing the underlying identity or creating linkable activity. Authentication is one key application — others include credential portability, sybil resistance, and selective disclosure. Applies to financial compliance (KYC registry membership), governance (anonymous voting), national identity (selective disclosure from government documents), and community membership (sybil-resistant access).

Private Identity

A bank needs to verify that counterparties and end users meet KYC, sanctions, and jurisdictional eligibility requirements without exposing personal data on chain or building cross-institutional dossiers. The same architecture must serve government registries, DAOs, and humanitarian programs whose users may be in jurisdictions where the issuer becomes unavailable, hostile, or destroyed.

Private Intent-Based Vaults

Allow institutional and DeFi actors to express trading or allocation intents that a vault executes privately: strategy parameters, order flow, and risk exposure stay hidden while deposited assets remain transparently custodied and redeemable. Auditors receive scoped disclosure; the public sees only aggregate state.

Private ISO 20022 Messaging & Settlement

Coordinate private ERC-20 settlements between banks using ISO 20022 as the instruction layer. The ISO message binds to the on-chain cash leg, while the cash leg itself settles privately via a shielded mechanism (privacy L2, shielded pool, or confidential token) with regulator-only visibility.

Private Messaging

Encrypted communication channels for financial institutions conducting blockchain transactions. Pre-trade negotiation, deal structuring, and counterparty communication contain sensitive information that must remain confidential between parties while supporting regulatory oversight and audit requirements. The solution requires end-to-end encryption with selective disclosure capabilities.

Private Money Market Funds

Tokenized money market funds providing yield-bearing treasury management for institutions. Unlike stablecoins (which typically don't earn yield), money market funds are productive assets generating returns. Institutions prefer MMFs over non-yield stablecoins for treasury management but require privacy for position sizes and yield strategies.

Private Money Market Funds

A treasurer subscribes USD 50M USDC to a tokenized T-bill money market fund. Position size, redemption timing, and yield attribution must be hidden from competitors and other fund participants. Fund NAV must be publicly verifiable on a daily or intraday cadence and must remain verifiable even if the fund operator goes offline; redemptions must continue without interruption under stress.

Private Oracles

Price feeds and data sources that protect query privacy - hiding which institutions are requesting specific information. Query patterns reveal trading intent, enabling front-running and information arbitrage. Going forward, the assumption is that oracles should be default private; the entire stack must be end-to-end with no information leakage.

Private Payments

Cross-border and domestic payment transfers where transaction details must remain confidential between parties. Transaction patterns reveal business relationships, purchasing behavior, and financial health - often more than any other data source. Privacy applies to both institutional and retail payment contexts.

Private Payments

A multinational bank executes daily institutional stablecoin transfers (USDC, EURC) between subsidiaries, mid-cap counterparties, and a humanitarian arm disbursing to recipients in adversarial jurisdictions. The bank needs amount and counterparty privacy on chain, selective disclosure for regulators by jurisdiction, integration with SWIFT/ISO 20022, and a separate rail where recipients have no client-side proving capability and intermediaries may be compelled or breached.

Private Procurement

Procurement and invoicing processes where bid prices, supplier relationships, payment terms, and contract details must remain confidential between parties. Both public and enterprise procurement involve competitive dynamics where premature disclosure distorts markets, enables collusion, or reveals strategic priorities.

Private PvP (cash to cash) Settlement via ERC-7573

Settle two stablecoin legs against each other atomically while keeping amounts and counterparties visible only to the transacting parties and their auditors. Each leg uses a shielded transfer layer for privacy; the ERC-7573 escrow pattern on both chains conditions release on verified finality of the opposite leg, so neither side settles without the other. The construction avoids the public amounts and timing leakage of plain HTLCs and avoids relying on time-locks for safety.

Private Read

Blockchain query privacy for institutions interacting with public blockchains. Institutions monitoring addresses, checking balances, or querying transaction history leak competitive intelligence through their read patterns. Query metadata reveals trading intent, portfolio composition, and counterparty relationships.

Private Registry

Operating authoritative registries (securities holders, business entities, licenses, environmental permits) on-chain where registry entries must be verifiable by authorized parties but the full registry state must not be publicly exposed. Distinct from authentication (which proves membership in a registry) — this use case is about institutions that *run* registries: maintaining records, processing updates, and enabling cross-border lookups, all with privacy.

Private Repo

Tokenized repurchase agreements where counterparties and transaction amounts must remain confidential. Repo is short-term secured lending - conceptually similar to DeFi flash loans, though TradFi has used this instrument for decades. The intraday lending market processes enormous volumes daily through centralized infrastructure. Privacy prevents counterparty exposure and funding cost arbitrage.

Private RWA Tokenization

Regulated real-world assets (RWAs) are tokenized on-chain to enable permissioned transfers of ownership and co-ownership. The solution requires private pricing and valuation with full history, unlinkable ownership and transfer histories, exportable ownership with accreditation proofs, and policy enforcement based on attestations with regulatory intervention capabilities.

Private Set Intersection (Circuit-based)

Two parties each hold a private set and want to compute a function over their shared elements without either party learning the raw intersection. Intersection-finding logic is embedded in a Boolean circuit alongside the aggregate function F, so the output is limited to F(intersection). The circuit is evaluated jointly using authenticated garbling or secret-shared circuits, and the raw matches are not revealed to either party.

Private Set Intersection (DH-based)

Two parties each hold a private set of identifiers and want to learn which elements they share without exposing the rest. This variant uses commutative encryption via elliptic-curve Diffie-Hellman: both parties blind their inputs with secret scalars, and the commutativity of scalar multiplication lets them compare double-blinded values without revealing the originals. The protocol runs bilaterally between the two parties.

Private Set Intersection (FHE-based)

Two parties want to learn which elements they share without exposing non-matching entries. This variant uses Fully Homomorphic Encryption: the receiver encrypts their set under an FHE scheme and sends the ciphertexts; the sender homomorphically evaluates a matching polynomial against its own plaintext set and returns masked encrypted results; the receiver decrypts to learn the intersection. The construction suits asymmetric set sizes, minimises round count, and reduces to LWE/RLWE hardness for post-quantum security.

Private Set Intersection (OPRF-based)

Two parties each hold a private set of identifiers and want to learn which elements they share without exposing the rest. This variant uses Oblivious Pseudorandom Functions built on OT extensions: each party acts as the OPRF evaluator for the other's inputs, producing pseudorandom tags that match only when the underlying elements match. Cuckoo hashing compresses communication to O(n + m) with small constants, so the protocol scales to millions of elements where the DH-based variant becomes impractical.

Private Shared State (FHE)

Enable N parties to jointly read and write shared on-chain state (balances, positions, order books, collateral pools) while keeping each party's individual data private from the others and from the infrastructure operator. This variant stores state encrypted on-chain under a shared Fully Homomorphic Encryption key, runs state transitions as homomorphic operations on ciphertexts, and controls reads through a threshold decryption committee.

Private Shared State (MPC + ZK / co-SNARKs)

Enable N parties to jointly read and write shared on-chain state (balances, positions, order books, collateral pools) while keeping each party's individual data private from the others and from the infrastructure operator. This variant secret-shares each party's inputs across a distributed prover network; the nodes jointly run an MPC protocol to compute a single zero-knowledge proof of a correct state transition; the proof is posted on-chain for verification.

Private Shared State (TEE)

Enable N parties to jointly read and write shared on-chain state (balances, positions, order books, collateral pools) while keeping each party's individual data private from the others. This variant stores state encrypted to an enclave public key; a Trusted Execution Environment decrypts inputs, runs the state transition at native speed, and posts updated encrypted state plus a remote-attestation report proving which code ran.

Private Smart Derivatives

A bank trades ERC-6123 derivatives (interest-rate swaps, FX forwards, simple options) with named counterparties. Margin balances and daily settlement deltas must remain hidden from competitors; settlement must run automatically on the daily cadence; regulators must retain audit access on demand. Trade size, direction, and notional are competitively sensitive.

Private Smart Derivatives (ERC-6123)

Banks need to run ERC-6123 interest-rate swaps on public chains without leaking margin balances, settlement amounts, and trade terms. The solution requires all economic values and trade details to be confidential while retaining automation and auditability for institutional scale adoption.

Private Stablecoin Shielded Payments

Provide stakeholder-only stablecoin transfers on an L2 or app-chain, with viewing-key or zero-knowledge-proof-based disclosure to regulators and auditors, and the ability to compose atomically with asset legs (DvP) or other cash legs (PvP). Hide amounts, counterparties, and memos from non-participants while still enforcing any issuer-level or regulatory policy bound to the stablecoin.

Private Stablecoins for Institutional Payments

Institutions want to use stablecoins as settlement cash without exposing amounts, counterparties, or workflow metadata to non-participants. The solution requires stakeholder-only visibility with selective disclosure and atomic settlement capabilities with assets.

Private Stocks

Tokenized equity trading where position sizes, trading activity, and ownership stakes must remain confidential. Traditional exchanges face competitive pressure from crypto-native platforms and seek tokenization to create new products while protecting institutional trading strategies from exposure.

Private Supply Chain

Supply chain provenance and integrity verification where commercial relationships, pricing, volumes, and routing must remain confidential between parties. Manufacturers, distributors, and retailers need to prove product authenticity and regulatory compliance to downstream buyers and regulators without exposing their supplier networks or logistics operations to competitors.

Private Trade Settlement

A treasury desk and a counterparty bank settle a EUR 25M corporate bond against EURC. Both parties want hidden amounts and counterparty identities, atomic execution, and selective regulator access. Some trades involve a bond on a privacy L2 against cash on Ethereum L1, forcing cross-network coordination.

Private Transaction Broadcasting

Hide transaction content from the public mempool before inclusion so that front-runners, sandwich bots, and competitors cannot observe or exploit pending trades. Transactions are routed through private relays or published as ciphertexts decrypted only after ordering, so adversaries see the transaction only once it is committed to a block.

Private Transaction Broadcasting

A trading desk routes large institutional orders against on-chain venues. Visible transactions in the public mempool enable front-running, sandwiching, and intent inference; the spread cost on a EUR 25M order is large enough to dominate fees for the year. The desk needs broadcasting infrastructure that hides the order content, the timing, or both, while preserving validity and ordering guarantees.

Private Treasuries

Corporate treasury operations on-chain where multi-entity organizations need to manage internal cash flows without revealing financing activity to competitors. Large corporations move billions daily between subsidiaries, and these internal transfers can reveal business strategy, regional performance, and capital allocation decisions.

Product Fhenix

Fhenix builds a CoProcessor that brings Fully Homomorphic Encryption (FHE) to EVM chains, enabling developers to compute directly on encrypted data without ever decrypting it. This allows dApps to offer on-chain privacy by default. At its core, Fhenix introduces CoFHE, a decentralized coprocessor that makes encrypted computation fast, scalable, and easy for Solidity developers to adopt.

Proof of Innocence (Association Set Proofs)

Let users prove their funds are not associated with illicit activity without revealing the deposit, transaction history, or counterparties. Two protocol variants exist: prove at withdrawal against a curated set root, or prove at deposit with proof propagation through subsequent transfers. Both rely on Merkle tree membership or exclusion proofs with zero-knowledge proofs and differ in timing, proof direction, and set management.

Railgun

Railgun is a set of smart contracts providing **shielded transfers and private DeFi interactions** on Ethereum and other EVM-compatible chains. It uses zkSNARKs to maintain a UTXO-like note system (commitments and nullifiers) that allows users to send, receive, and interact with DeFi protocols while hiding wallet balances and transaction details.

Recipient-Derived Receive Addresses

Generate Ethereum receive addresses deterministically from a long-lived recipient secret plus per-event context (e.g., event identifier, contract address, sequence number), such that an observer without the secret cannot predict, recognize, or link the addresses, while the recipient (with their secret) can re-derive the corresponding private key and spend the funds.

Relay-Mediated Proving

Split a typical ZK proof flow into two roles. The client signs a portable signed message offline. A relay generates the SNARK over that message and submits it on-chain. To prevent a front-runner from lifting the proof off the mempool and re-submitting it from their own address, the proof binds to the relay's submitter address as a public input that the application contract checks against `msg.sender`.

Renegade

Renegade is a decentralized dark pool protocol for trading digital assets. It combines **maliciously-secure MPC** (for private order matching) with **zkSNARK proofs** (for verifiable settlement), ensuring balances, orders, and trade history remain confidential while still settling on-chain.

Resilient Disbursement Rails

Deliver private humanitarian disbursements to recipients in adversarial jurisdictions, with off-ramp unlinkability as the primary cryptographic requirement. Off-ramp unlinkability matters because every documented financial-surveillance prosecution in the public record pivoted on a KYC'd exchange account, a merchant identifier visible to a domestic bank, or a subpoenaed exchange record; chain analytics on its own has not deanonymized a specific recipient. The cash-out point is therefore the load-bearing privacy boundary in the field, not the on-chain transfer. Recipients hold tamper-resistant smartcards with no client-side ZK proving capability, intermittent or absent internet connectivity, and a high probability of device loss or seizure. Every party in the path between funder and recipient (implementing partner, identity-layer operator, relay, custodian, exchange) is assumed to eventually be breached, compelled, or inherited by a hostile successor.

Resilient Identity Continuity

Maintain the ability to prove identity attributes on-chain after the original credential issuer becomes unavailable, hostile, or ceases to exist. Extends [Private Identity](private-identity.md) to an issuer-hostile threat model: the issuer may refuse new issuance, mass-revoke credentials, publish false revocation lists, or go permanently offline. Holders need credential survival, recovery without issuer cooperation, and verification that requires no issuer or registry contact.

Safe Proof Delegation

Let a user delegate zero-knowledge proof generation to an external prover (a privacy RPC, a hardware accelerator, or a third-party service) without giving that prover the ability to forge, redirect, or overspend. The user signs a canonical intent digest that binds every material parameter; the prover can produce a valid proof that executes exactly that intent and nothing else.

Selective disclosure (viewing keys + zero-knowledge proofs)

Provide on-demand, scoped visibility into confidential trades and positions via threshold-controlled viewing keys or zero-knowledge predicate proofs that answer specific regulator questions. The institution keeps plaintext private by default and releases only the minimum information required to satisfy a specific, logged mandate.

Shielding

Enable confidential transfers by shielding balances, sender, and receiver, while still allowing regulators and auditors to verify via selective disclosure (viewing keys, proofs). The logic generalizes beyond ERC-20 to any transferable asset.

Shutter

Shutter Network provides **encrypted mempool** infrastructure that prevents MEV extraction and front-running by encrypting transactions until they are included in blocks, using **threshold cryptography** for decryption.

Social Recovery

Let a quorum of guardians authorize rotation of the signing key or enrollment anchor for an account or identity. A holder recovers after key loss or compromise without the original issuer, custodian, or centralized service.

Soda Labs

Soda Labs develops **open-source Garbled Circuit-based SMPC (Secure Multiparty Computation)** tools that enable confidential smart contracts and encrypted data processing directly on EVM-compatible networks. The Garbled Circuit–based confidential compute engine operates in two modes: integrated and plug-and-play. In the integrated mode, the MPC protocol is embedded within the consensus layer to produce a fully fledged, privacy-preserving L1 or L2. The plug-and-play mode, on the other hand, is run by an external network (called Bubble) to enable privacy on existing chains with minimal integration effort, while also supporting cross-chain functionality.

Space and Time

A SQL data oracle which is ZK-verifiable onchain. Space and Time allows smart contracts and API clients to run SQL queries over verifiably correct (attested), onchain events or signed, tamperproof offchain data and receive both: (a) the query result and (b) a zero-knowledge proof that the computation was performed correctly over untampered tables. The proof can be verified by an EVM-compatible verifier contract, enabling downstream smart contract logic to safely act on the result without trusting offchain execution or reprocessing data onchain.

Stateless Plasma Privacy

Use a stateless Plasma architecture to enable private token transfers where transaction data stays with users client-side, only commitments are posted on-chain, and validity is proven via zero-knowledge proofs. This provides strong transaction-graph privacy with L2 scalability, at the cost of moving data-availability responsibility to users.

Stealth Addresses

Enable unlinkable transfers on a transparent chain by deriving a one-time destination address per transaction using a Diffie-Hellman shared secret between sender and receiver keys. Observers see a transfer to a fresh address; only the recipient can detect and spend the funds.

TACEO Merces

TACEO Merces is an implementation of **Private Shared State (PSS)** for confidential stablecoin transfers on EVM chains. It combines multi-party computation (MPC) with zero-knowledge proofs (Groth16 via co-SNARKs) to hide transfer amounts while maintaining on-chain verification. Currently deployed on Base and Arc testnets.

TEE Key Manager

Run an institutional key manager inside an attested hardware-isolated environment. Keys are generated or imported inside the enclave, which enforces a signing policy and produces signatures while keeping private key material isolated from the host and operator. External systems bind the signer public key and policy hash to an approved attested measurement via an attestation verifier; on-chain registries can record this binding for audit.

TEE-Assisted Network Anonymity

Hide who is sending transactions or querying state at the network layer with latency low enough for interactive workloads. Content-privacy patterns hide what is in a transaction but not who submitted it; IP addresses, timing, and query patterns still leak sender identity. A client-side Trusted Execution Environment secret-shares the outbound payload across a set of servers so that no single server sees the cleartext, and the anonymity guarantee survives a compromise of the TEE at the cost of liveness.

TEE-Based Privacy

Use hardware-isolated execution environments to protect sensitive computation from the host operating system, hypervisor, and operator. The pattern provides hardware-enforced confidentiality and integrity for code and data while running, so privacy-preserving operations can be performed without exposing plaintext to infrastructure providers. This is a foundational pattern; specific applications (key management, settlement, matching) compose on top.

Threshold-encrypted mempool

Prevent miner-extractable-value extraction by encrypting transaction content before mempool submission and releasing the decryption key only after block ordering is committed. A distributed committee holds threshold key shares, so no single party can decrypt prematurely. The result is cryptographic protection against front-running, back-running, and sandwich attacks, without handing trust to any one relay.

TLS payment bridge

Enable trust-minimized fiat-to-on-chain swaps by combining instant payment rails with zero-knowledge TLS proofs. A taker pays fiat to a liquidity provider through a standard bank or payment-app rail, runs a zero-knowledge TLS session against the provider's confirmation page, and submits a proof to an on-chain escrow contract. The contract verifies that the payment occurred and releases crypto to the taker. No party custodies funds on behalf of the other, and full bank or account details are never revealed on-chain.

TX-SHIELD

TX-SHIELD builds modular privacy layers/solutions for institutional finance and AI systems: - **TX-SHIELD** — a regulated private payment layer/solution built on MPC-based encryption and threshold key control. It enables confidential settlement for stablecoins, RWAs, and bonds while ensuring regulator-auditable transparency. Transactions are visible only to stakeholders, while regulators can access details through granted audit keys.

US / SEC

The SEC is generally **restrictive but evolving**. Crypto assets deemed securities must follow full registration and disclosure rules. Recent clarity has emerged:

User-controlled viewing keys

In many privacy-preserving systems the institution operating the service holds viewing keys or equivalent decryption capabilities for all user transactions, which gives it surveillance power over users even when on-chain data is encrypted. User-controlled viewing keys invert that model: the user holds the private viewing key and selectively shares derived sub-keys with specific parties (regulators, auditors, counterparties) for scoped, time-limited access. This pattern is the institution-to-user complement to selective disclosure, which covers the workflow once a scoped key has been shared.

Vendor/Pattern: Miden

Polygon Miden is a privacy focused Ethereum rollup (zk-zk-rollup) that prioritizes throughput and privacy over full EVM compatibility. It uses the Miden VM, a STARK-based virtual machine designed for client-side proving.

vOPRF Nullifiers

Generate deterministic, scope-bound nullifiers using a verifiable oblivious pseudorandom function (vOPRF) whose secret key is held by a threshold committee. The client blinds its input, the committee jointly evaluates the OPRF, and the client unblinds the response to derive a nullifier. The server key prevents offline reconstruction from a leaked client secret; verifiability lets the client detect a malicious committee response.

White-Label Infrastructure Deployment

A bank wants to launch a private-stablecoin service under its own brand within 12 months. Building privacy infrastructure from scratch would take years of R&D; the bank wants to license vendor technology and operate the resulting stack under controlled governance, on dedicated infrastructure, with regulatory-aligned change control.

Zama

Zama develops **open-source FHE (Fully Homomorphic Encryption)** tools that enable confidential smart contracts and encrypted data processing directly on EVM-compatible networks.

ZK Proof Systems

Give designers a decision framework for choosing a zero-knowledge proof system on Ethereum. A zero-knowledge proof lets one party prove a statement is true without revealing the inputs. The system's commitment scheme (elliptic-curve pairings, discrete log over curves, collision-resistant hashes, or lattices) drives its post-quantum posture; the setup model drives its trust assumption; proof size and prover and verifier cost drive deployment economics.

ZK Wrappers

Verify an off-chain digital signature over an existing credential inside a ZK circuit. The verifier learns that a valid signature exists and that chosen predicates hold over the signed payload, and nothing else.

zk-KYC/ML + ERC-734/735 identity claims

Publish identity claims on-chain that are backed by a zero-knowledge proof of an off-chain KYC or AML check, instead of a flat signature from a whitelisted issuer. The identity contract (ERC-734/735) holds the claims; a verifier contract checks the zero-knowledge proof at claim ingestion or at access time. The on-chain public sees that a qualified check was performed under a specific policy, without learning the subject's personal data.

zk-promises (stateful anonymous credentials)

Let a service enforce mutable compliance, moderation, or rate-limit rules on anonymous users without identifying them. The user holds a zk-object with private mutable state (reputation, compliance flags, ban status) as a commitment on an append-only bulletin board. The provider posts asynchronous callbacks that update the state without knowing which user is affected. On each interaction the user proves predicates over the current state via a zero-knowledge proof.

zk-TLS

Export verifiable data or identity attributes from a TLS-protected website into a form that an on-chain contract or a counterparty can check. The user jointly runs a TLS session with a notary; the notary signs a transcript of the session; the user produces a zero-knowledge proof over the signed transcript that discloses only the fields required downstream.

ZKsync Prividium

An Ethereum-secured blockchain platform purpose-built for institutions that demand privacy, compliance, and full control of their data. Prividium is part of ZKsync's suite of enterprise solutions, designed for real-world asset tokenization, private capital markets, and institutional-grade financial infrastructure with selective disclosure capabilities.