feat(vendor): add Bermuda

vendors/bermuda.md

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+---
+title: "Vendor: Bermuda"
+status: ready
+website: https://bermudabay.xyz/
+category: privacy-layer
+ethereum_aligned: true
+last_reviewed: 2026-09-03
+maturity: testnet
+---
+
+# Bermuda – Privacy and compliance layer for the EVM
+
+## What it is
+
+Bermuda is a privacy and compliance layer deployed as contracts on existing
+EVM chains. Funds sit in a smart contract as shielded UTXOs: balances, amounts and
+counterparties are hidden by zero-knowledge proofs generated on the user's
+device, and every transfer proves in zero knowledge that it satisfies the
+issuer's policy for that token. Sanctions screening, retroactive flagging with
+Proof of Innocence, issuer policies and clawback are enforced by the smart
+contract and its circuits, not by an operator who reads transactions. It is
+middleware, not a chain, wallet or custodian.
+
+## Fits with patterns
+
+- [Shielding](../patterns/pattern-shielding.md)
+- [Proof of Innocence](../patterns/pattern-proof-of-innocence.md)
+- [Compliance Monitoring](../patterns/pattern-compliance-monitoring.md)
+- [Regulatory Disclosure Keys & Proofs](../patterns/pattern-regulatory-disclosure-keys-proofs.md) - issuer viewing keys
+- [Private Stablecoin Shielded Payments](../patterns/pattern-private-stablecoin-shielded-payments.md)
+- [Stealth Addresses](../patterns/pattern-stealth-addresses.md)
+- [Private Transaction Broadcasting](../patterns/pattern-private-transaction-broadcasting.md)
+- [Immutable Guarantees](../patterns/pattern-immutable-guarantees.md)
+- [Social Recovery](../patterns/pattern-social-recovery.md)
+- [DvP (ERC-7573)](../patterns/pattern-dvp-erc7573.md) - partial fit: cross-chain DvP via ERC-7888 proofs
+
+## Not a substitute for
+
+- Not a privacy L2 or separate ledger: everything runs on the host chain; no
+  sequencer, coprocessor network or bridge in the transaction path
+- Not a wallet or custodian: users keep their keys in existing wallets
+
+## Architecture
+
+- **Smart contract**: holds funds as shielded UTXOs: commitments in
+  an incremental Merkle tree, chain-bound nullifiers, one `transact` entry point.
+  Notes are encrypted to the recipient's x25519 key and emitted as events.
+- **Proofs and keys**: Noir circuits, Barretenberg as ZK proving backend, 
+  client-side proving in WASM. Spend authorization is Schnorr over Grumpkin; FROST
+  threshold Schnorr puts a Safe's owners behind a shielded account.
+- **Issuer policy engine**: the token owner (typically a Safe) sets a
+  per-token policy — spending limit per period, allow and deny lists, an
+  optional issuer viewing key — that every transfer proves in-circuit against
+  the smart contract's live policy root. The circuit checks a commitment to the policy's
+  fields, so an issuer can publish its rules or keep them private; list
+  membership stays off-chain either way. The viewing key yields an encrypted
+  view of that token's transfers; the issuer can claw back funds with a proof.
+- **Compliance Gateway**: deposits bind the compliance engine's key and an
+  expiry block into the proof, so a delisted address cannot replay an
+  approval. Flagged deposit ids live in an indexed Merkle tree: private
+  withdrawals prove exclusion, disclosed ones inclusion. Depositors and
+  recipients are also screened on-chain by the Chainalysis sanctions oracle.
+- **Roles**: the smart contract and verifiers are non-upgradeable. A governor
+  sets fees,
+  recovery parameters and the public-withdrawal delay and assigns a pauser,
+  who halts `transact` and `claim` for incident response.
+- **Cross-chain DvP**: two smart contracts act as escrows: a leg is locked,
+  released
+  once the counterparty's lock is proven present, or reclaimed on a proof of
+  absence after the cutoff — ERC-7888 broadcast proofs, no coordinator. Linea
+  proof of concept, June 2026.
+- **Products**:
+  - SDK suite: `core-sdk`, `issuer-sdk`, `safe-sdk`, `fireblocks-sdk`, etc.
+  - E2E apps: Private Safe Wallet, universal/mobile app in progress
+- **Services**:
+  - E2E enterprise applications, from development through operations to compliance, for instance:
+    - Exclusive OTC/DvP/RFQ networks (always private, cross-chain capable)
+    - Customized private wallet UX, especially enterprise- and institution-focused
+    - Accounting/reporting and compliance adapters, and middleware
+  - MPC overlay upgrades on top of institutions’ physical HSMs through the partnership with Utila
+
+## Privacy domains
+
+- Balances, amounts and the transaction graph are hidden. Stealth addresses
+  keep public 3rd party protocol interactions unlinkable.
+- Two exits: private (exclusion proof, deposit not revealed) and disclosed (if flagged by the compliance engine).
+- Disclosure is scoped: an issuer viewing key decrypts transfers of that
+  issuer's token and nothing else; the compliance engine sees the depositor's
+  public address and never activity inside the contracts.
+
+## Enterprise demand and use cases
+
+- **Stablecoin, deposit-token and RWA issuers**: private or public policies,
+  issuer viewing key and clawback give the issuer the controls expected of a
+  regulated token while holders keep confidential balances
+- **Regulated tokenised assets**: the privacy example (Box 5) in the Global
+  Layer One white paper *Programmable Compliance* (June 2026, with Banque de
+  France, the IMF, Kinexys by J.P. Morgan, MAS and Standard Chartered)
+- **Banks and institutions**: shielded treasury under Safe multisig,
+  recoverable accounts, atomic cross-chain DvP and PvP, bilateral repo and OTC
+  swaps
+- **Wallets and neobanks**: shielded balances and transfers behind existing UX
+- **Payments**: payroll, card settlement, x402
+- **Asset management**: shielded ERC-4626 positions, private yield and DeFi,
+  private order books
+
+## Technical details
+
+- Curves in use: BN254 (proof system), Grumpkin (signatures), Curve25519 (encryption)
+- Proof system: Noir, Barretenberg (UltraHonk); no circuit-specific trusted setup (universal SRS)
+- Signing: Schnorr, FROST, Golden DKG
+- Encryption: XChaCha20-Poly1305
+
+Post-quantum implementation in progress.
+
+## Strengths
+
+- Issuer self-onboarding: any token owner can attach and update a policy
+  without Bermuda's involvement
+- Signer-agnostic: multisig, passkey and MPC signers, plus account recovery
+- Compliance is proved, not observed: screening, flagging, sanctions, issuer
+  policy and Proof of Innocence are verified by contract and circuit
+- Issuer powers are strong by design: an issuer keeps the abilities it has on
+  the public chain, selective freezing and clawback included, in the shielded domain too
+- Trust model is the host chain plus standard zk-SNARK assumptions: no Trusted
+  Execution Environment, multi-party computation committee or coprocessor
+  network in the confidentiality path
+- No new ledger: same chain, same tokens, same wallets
+- Exit is protocol-level: withdrawal is always available, private for clean
+  and disclosed for flagged lineage; the operator cannot freeze an account
+
+## Risks and open questions
+
+- Testnet stage: no mainnet deployment, third-party audit or bug bounty published
+- Anonymity depends on activity in the contracts per chain and asset
+
+## Links
+
+- [Bermuda website](https://bermudabay.xyz/)
+- [Documentation](https://docs.bermudabay.xyz/)
+- [Architecture](https://docs.bermudabay.xyz/tech/architecture)
+- [Contracts](https://docs.bermudabay.xyz/tech/contracts)
+- [Compliance overview](https://docs.bermudabay.xyz/compliance-solution/how-compliance-works)
+- [GitHub organization](https://github.com/BermudaBay)
+- [GL1 white paper: Programmable Compliance, Box 5](https://global-layer-one.org/pdf/gl1-pc-whitepaper-22-jun-2026.pdf)
+- [Linea × Bermuda settlement PoC](https://cryptobriefing.com/linea-bermuda-private-cross-chain-settlement/)
+- [Utila x Bermuda partnership](https://utila.io/blog/utila-bermuda-confidential-custody-central-banks)