ARBITRUM PRIVACY

The Largest L2 Has Zero Privacy.

Q: Is Arbitrum privacy the same as encrypted computation (FHE)?

No. Arbitrum privacy is an expression of the H33 Privacy Layer that protects evidence, identity, and chain interaction using zero-knowledge proofs, selective disclosure, and data minimization. Encrypted computation over data that never decrypts is a separate mechanism (FHE). The two share the word privacy but not the mechanism.

Q: Does Arbitrum produce the proof?

No. The portable evidence is produced by H33-74 and its verdict is rendered by Verification. Arbitrum is the reference environment the 32-byte commitment anchors to; it never generates or verifies the attestation.

Q: When should I choose a different chain for privacy?

Choose Bitcoin privacy when settlement permanence matters most, or Ethereum, Base, or Avalanche privacy when your evidence naturally settles there. The same H33-74 attestation is portable across all supported chains.

Related · tier-1 reading. For the privacy story end-to-end — FHE + STARK proof + portable artifact, see Privacy Layer.

$15B+ in TVL with every position, every yield strategy, every bridge transaction visible to anyone. Front-runners, competitors, and adversaries read your DeFi positions in real time. H33 adds post-quantum privacy to the largest L2 by value locked.

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DEFINITION

Arbitrum privacy is the expression of the H33 Privacy Layer on the Arbitrum L2. It protects the privacy of your evidence, identity, and chain interaction while anchoring a portable, independently verifiable attestation to Arbitrum. The privacy mechanism is a combination of zero-knowledge proof (ZK — STARK, no reveal), selective disclosure, and data minimization; the portable evidence itself is produced by H33-74 (the 74-byte post-quantum attestation), and the verdict is rendered by Verification. Arbitrum is the reference environment the evidence anchors to — a 32-byte commitment in calldata — never the producer of the proof.

Why this exists: the largest L2 by value locked exposes every position, yield strategy, and bridge transaction to front-runners and competitors. Arbitrum itself provides ordering and settlement — it provides no privacy and no post-quantum evidence. The Privacy Layer supplies both, without asking you to trust Arbitrum with anything more than a hash.

EXPOSURE COMPARISON

What changes when H33 is in the path

Native Arbitrum

× Visible DeFi positions
× Visible yield strategies
× Visible bridge transactions
× Visible L2 balances
× Visible gas optimization patterns
× Visible swap routing
× Visible lending positions
× Visible liquidity provision

H33 Protected

✓ Encrypted position workflow
✓ Attested execution proof
✓ Hidden strategy metadata
✓ Proof-only yield verification
✓ 32-byte calldata commitment
✓ Independent verification
✓ Post-quantum attestation
✓ Replay-grade evidence

ATTESTATION RECEIPT

What a verified attestation looks like

h33-74 attestation receipt
H33-74 ATTESTATION RECEIPT

Receipt ID:     h74_attest_...
DAG Root:       0x... (depth: 4, nodes: 12)
Proof Hash:     0x... (STARK, 128-bit PQ security)
Replay Ref:     replay://h33.ai/r/...
Chain Anchor:   Arbitrum One -- block ...
Commitment:     0x... (32 bytes in calldata)

SIGNATURES:
  ML-DSA-65:    VALID (3,309 bytes -- MLWE lattice)
  FALCON-512:   VALID (666 bytes -- NTRU lattice)
  SLH-DSA-128f: VALID (17,088 bytes -- hash-based)

VERIFICATION:   ALL CHECKS PASSED (20/20)
HATS LEVEL:     Level 1 Conformance
CACHEE KEY:     cachee://h33.ai/c/...

Replay This Attestation -->    Verify Independently -->

ATTESTATION PIPELINE

Five stages. 32 bytes on-chain.

DeFi Position

Encrypted inputs from protocol

-->

STARK Proof

Constraint satisfaction without reveal

-->

PQ Signatures

ML-DSA + FALCON + SLH-DSA triple sign

-->

Cachee Store

Full proof bundle persisted off-chain

-->

EVM Calldata

32-byte commitment on Arbitrum

32 bytes on-chain. Full proof off-chain. Three PQ families. Zero data revealed.

DISCLOSURE BOUNDARY

What crosses the attestation boundary

NOT REVEALED

× DeFi positions
× Yield strategies
× Bridge transactions
× L2 balances
× Gas optimization
× Swap routing
× Lending positions
× Liquidity provision

ONLY REVEALED

✓ Cryptographic validity
✓ Compliance proof
✓ Position sufficiency
✓ Attestation commitment
✓ Verification status
✓ Replay availability
✓ PQ signature bundle
✓ Chain anchor hash

DECISION GUIDANCE

When to use Arbitrum privacy — and when not to

When to use this

✓ Use this when your positions, yield strategies, or bridge flows already live on Arbitrum and you need portable proof anchored there.
✓ Use this when you want low-cost, high-throughput EVM anchoring with a 32-byte commitment.
✓ Use this when you need to prove compliance to a regulator while revealing nothing to competitors.

When NOT to use this

× Do not use this when you need maximum settlement permanence — use Bitcoin privacy instead.
× Do not use this when your evidence naturally settles on Ethereum L1 or another chain — use Ethereum privacy, Base privacy, or Avalanche privacy.
× Do not use this when the need is encrypted computation over data that never decrypts — that is a different mechanism (FHE); use FHE instead. Anchoring the result back to Arbitrum still routes through this page.

BOUNDARY QUESTIONS

Exactly what Arbitrum privacy is — and is not

1. What privacy property is provided?
Confidentiality of your evidence, identity, and on-chain interaction: positions, strategies, and counterparties stay hidden while a proof of validity and compliance is published.
2. What is specific to Arbitrum?
The reference environment: an Arbitrum L2 calldata commitment (32 bytes), low fees, high throughput, and inherited Ethereum settlement. The chain is where the evidence anchors — it is not the producer of the evidence.
3. What remains supplied by H33-74?
The portable evidence itself. H33-74 produces the 74-byte post-quantum attestation that travels across every chain unchanged; Arbitrum only stores its commitment.
4. Is the mechanism ZK, FHE, minimization, selective disclosure, or a combination?
A combination: zero-knowledge STARK proof, selective disclosure, and data minimization. FHE (encrypted computation) is a distinct mechanism and is used only if encrypted compute is genuinely in the workflow — see FHE.
5. What does the chain itself NOT provide?
Arbitrum provides no privacy, no post-quantum signatures, and no verification logic for the attestation. It orders and settles a 32-byte commitment — nothing more.
6. How is the evidence independently verified?
Verification renders the verdict: re-derive the commitment from the published bundle and check the three post-quantum signature families offline with the open-source verifier — no trust in H33 or Arbitrum required.
7. When should another chain or mechanism be preferred?
Prefer Bitcoin for maximum permanence; Ethereum, Base, or Avalanche when settlement lives there; and FHE when the need is computing on data that never decrypts.

FAQ

Arbitrum privacy — questions

Is Arbitrum privacy the same as encrypted computation (FHE)?

No. Arbitrum privacy is an expression of the Privacy Layer — it protects evidence, identity, and chain interaction using ZK, selective disclosure, and minimization. Encrypted computation over data that never decrypts is a separate mechanism (FHE), covered at /fhe/. The two share the word “privacy” but not the mechanism.

Does Arbitrum produce the proof?

No. The proof is produced by H33-74 and its verdict is rendered by Verification. Arbitrum is the reference environment the 32-byte commitment anchors to — it never generates or verifies the attestation.

When should I choose a different chain?

Choose Bitcoin privacy when permanence matters most, or Ethereum, Base, or Avalanche privacy when your evidence naturally settles there. The same H33-74 attestation is portable across all of them.