Review of Private Transaction Broadcasting approach and related cards by cygnusv · Pull Request #213 · ethsystems/map

cygnusv · 2026-10-28T12:15:54Z

What are you adding?

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Enterprise Use Case
Update to existing content
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Description

Phase 1 review of the Private Transaction Broadcasting approach and the cards it links, for the encrypted mempool approach cycle.

Approach: new Private Relay sub-approach, now the default for orders that must reach the chain. Encrypted Mempools ratings aligned with the threshold pattern, plus the Ethereum L1 status (LUCID, FOCIL) and three open questions.
Threshold-Encrypted Mempool: cr from high to medium. The sender stays visible and builders can refuse ciphertexts; it reaches high once inclusion lists carry sealed transactions. Keys are released once the ordering is committed, not after finality.
Other patterns: FOCIL and Private Transaction Broadcasting updated; Shutter repository and SUAVE fixes; Network Anonymity re-reviewed, date only.
Vendors: Shutter and Flashbots brought up to date; SUAVE archived.
Links: five trading use cases, the Trading domain and the glossary.

The cr change is the main judgement call; happy to discuss.

Checklist

I've checked this doesn't duplicate existing content
All links work
Info is accurate

rymnc · 2026-10-29T09:38:50Z

- **Networks:** live on Gnosis Chain; Ethereum integration planned
+- **Networks:** Gnosis Chain mainnet (encrypted mempool, 7 keypers with a threshold of 4); Shutter API on Gnosis Chain and Chiado
+- **Ethereum:** an out-of-protocol proof of concept with Primev's mev-commit was announced for the Hoodi testnet in December 2025 (3-of-5 keypers, builders commit before keys are released). The mainnet launch had not happened as of September 2026.
+- **Enshrinement:** Shutter authored [EIP-8105](https://eips.ethereum.org/EIPS/eip-8105) (Draft), an enshrined encrypted mempool. Its bid to headline the Hegotá upgrade was withdrawn in February 2026 in favour of LUCID ([EIP-8184](https://eips.ethereum.org/EIPS/eip-8184)), which the team now supports for the upgrade after Hegotá.


the february 2026 shutter post backs lucid as a Hegotá headliner. the september 2026 brainbot update says only that the team decided to pursue LUCID with validator allowlisted proposers. neither source names the upgrade after hegotá.

suggestion: drop the fork claim.

Suggested change

- **Enshrinement:** Shutter authored [EIP-8105](https://eips.ethereum.org/EIPS/eip-8105) (Draft), an enshrined encrypted mempool. Its bid to headline the Hegotá upgrade was withdrawn in February 2026 in favour of LUCID ([EIP-8184](https://eips.ethereum.org/EIPS/eip-8184)), which the team now supports for the upgrade after Hegotá.

- **Enshrinement:** Shutter authored [EIP-8105](https://eips.ethereum.org/EIPS/eip-8105) (Draft), an enshrined encrypted mempool. Its bid to headline the Hegotá upgrade was withdrawn in February 2026 in favour of LUCID ([EIP-8184](https://eips.ethereum.org/EIPS/eip-8184)), which the team now supports.

The Brainbot update set “Have an EM EIP ready to propose as I* Headliner” as a goal, so I kept the sentence, but updated it with the source.

Wrt to everything else, agreed on all your comments, see 6d5bf17.

oskarth

Thanks David, nice work. I agree with moving encrypted mempools to cr: medium, and it's consistent across the pattern, the approach, the table and the pre-trade card now. Private Relay as the default makes sense for L1 too, since there's no encrypted mempool live there yet.

I left three comments I'd like fixed before merge (Shutter on Gnosis, the 88% number, the OTC rating) and three small nits.

oskarth · 2026-11-04T04:59:51Z

 ## What it is

-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. It is live on Gnosis Chain, with Ethereum integration planned.
+Shutter Network provides encrypted-mempool infrastructure that prevents MEV extraction and front-running by encrypting transactions until their ordering is committed, using threshold cryptography for decryption. Brainbot develops it. Shutterized Gnosis Chain has been live since July 2024, opt-in through a Shutter RPC. On Ethereum mainnet no Shutter encrypted mempool is live as of October 2026.


Gnosis archived its Shutter docs on 3 September. The archived page says Shutter is "no longer part of Gnosis Chain". Brainbot's September update still says the keypers are running, though, so I'd mention both instead of just saying "in production".

The same wording is also in shutter.md:32, :43, :51, pattern-threshold-encrypted-mempool.md:50, :59, pattern-pretrade-privacy-encryption.md:64 and approach-private-broadcasting.md:24, :133, :213. Maybe check maturity: production on line 4 too.

Also, the docs link at pattern-threshold-encrypted-mempool.md:116 now goes to an empty page. The spec is in gnosischain/specs.

Suggested change

Shutter Network provides encrypted-mempool infrastructure that prevents MEV extraction and front-running by encrypting transactions until their ordering is committed, using threshold cryptography for decryption. Brainbot develops it. Shutterized Gnosis Chain has been live since July 2024, opt-in through a Shutter RPC. On Ethereum mainnet no Shutter encrypted mempool is live as of October 2026.

Shutter Network provides encrypted-mempool infrastructure that prevents MEV extraction and front-running by encrypting transactions until their ordering is committed, using threshold cryptography for decryption. Brainbot develops it. Shutterized Gnosis Chain went live in July 2024, opt-in through a Shutter RPC. In September 2026 Gnosis archived its Shutter docs, saying Shutter is no longer part of Gnosis Chain ([Gnosis docs](https://github.com/gnosischain/documentation/blob/main/archives/Shutter/README.md)); Brainbot's September update still reports an active keyper set. On Ethereum mainnet no Shutter encrypted mempool is live as of October 2026.

Done, with your text, and the same change everywhere you listed. pattern-private-transaction-broadcasting.md:50 had it too, so I changed that as well. The Gnosis docs link now points to gnosischain/specs. I kept maturity: production on the vendor card, since the Shutter API still runs (Brainbot's update: production API keyper set 5 of 5 online).

oskarth · 2026-11-04T04:59:51Z

+|---|---|---|---|---|
+| **Maturity** | production | production | prototyped | prototyped |
+| **Context** | both | i2i | both | both |
+| **CROPS** | CR:low O:part P:part S:med | CR:med O:y P:full S:med | CR:med O:part P:part S:med | CR:med O:part P:full S:med |


Line 100 now sends matched OTC trades through the Private Relay. So OTC can be censored the same way as the relay (a builder can just drop the bundle). But the relay is cr: low and OTC is still cr: medium, here and on line 93. Should OTC be low too? Or if the venue adds something for inclusion, could you say what?

Suggested change

| **CROPS** | CR:low O:part P:part S:med | CR:med O:y P:full S:med | CR:med O:part P:part S:med | CR:med O:part P:full S:med |

| **CROPS** | CR:low O:part P:part S:med | CR:low O:y P:full S:med | CR:med O:part P:part S:med | CR:med O:part P:full S:med |

Agreed and fixed

oskarth · 2026-11-04T04:59:51Z

+
+**Threat model:**
+- A relay or builder that sees the order can trade ahead of it; contracts and reputation are the only enforcement
+- Inclusion waits for a reached builder to win a slot; three builders produced about 88% of MEV-Boost blocks in late September 2026


I couldn't get 88% from relayscan. On the daily pages, Titan, BuilderNet and Quasar had between 90.6% and 95.9% of MEV-Boost blocks every day from 22 to 30 September (93.9% on the 25th). Linking a daily page also fixes Aaryamann's point that the front page changes over time. The same line is in pattern-private-transaction-broadcasting.md:96.

Suggested change

- Inclusion waits for a reached builder to win a slot; three builders produced about 88% of MEV-Boost blocks in late September 2026

- Inclusion waits for a reached builder to win a slot; three builders produced over 90% of MEV-Boost blocks on each day from 22 to 30 September 2026 ([relayscan](https://www.relayscan.io/stats/day/2026-09-25))

Fixed. For reference, the 88% figure comes from the EIPs post. I assume that number was current at that time.

oskarth · 2026-11-04T04:59:51Z

 ## Intent

-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.
+Prevent maximal extractable value (MEV) 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. Shutter runs this in production on Gnosis Chain. On Ethereum no encrypted mempool is live: LUCID ([EIP-8184](https://eips.ethereum.org/EIPS/eip-8184)), the leading proposal to enshrine one, is a Draft and is not scheduled for Hegotá.


Nit: encryption doesn't prevent back-running. After decryption anyone can trade right after the transaction, and LUCID and Shutter/mev-commit both allow this on purpose. I also put the Gnosis change in here.

Suggested change

Prevent maximal extractable value (MEV) 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. Shutter runs this in production on Gnosis Chain. On Ethereum no encrypted mempool is live: LUCID ([EIP-8184](https://eips.ethereum.org/EIPS/eip-8184)), the leading proposal to enshrine one, is a Draft and is not scheduled for Hegotá.

Prevent maximal extractable value (MEV) 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 and sandwich attacks, without handing trust to any one relay; back-running after decryption stays possible. Shutter ran this on Gnosis Chain from July 2024; Gnosis archived its Shutter docs in September 2026. On Ethereum no encrypted mempool is live: LUCID ([EIP-8184](https://eips.ethereum.org/EIPS/eip-8184)), the leading proposal to enshrine one, is a Draft and is not scheduled for Hegotá.

Agreed, used your wording

oskarth · 2026-11-04T04:59:51Z

 ## Intent

-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.
+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. FOCIL is scheduled for inclusion in the Hegotá upgrade, estimated for mid-2027.


Nit: I couldn't find a date for FOCIL in EIP-8081. I think mid-2027 comes from Forkcast, so maybe link it.

Suggested change

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. FOCIL is scheduled for inclusion in the Hegotá upgrade, estimated for mid-2027.

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. FOCIL is scheduled for inclusion in the Hegotá upgrade ([EIP-8081](https://eips.ethereum.org/EIPS/eip-8081)); no date is set, and [Forkcast](https://forkcast.org/upgrade/hegota) projects mid-2027.

Fixed, but the Forkcast link just says 2027, so I went with that.

oskarth · 2026-11-04T04:59:51Z


 ## [Unreleased]

+- fix(approach): Phase 1 review of [Private Transaction Broadcasting](approaches/approach-private-broadcasting.md) for the encrypted mempool cycle, with a new Private Relay sub-approach.


Nit: "Phase 1" and "cycle" are our internal terms. People reading the changelog won't know what they mean.

Suggested change

- fix(approach): Phase 1 review of [Private Transaction Broadcasting](approaches/approach-private-broadcasting.md) for the encrypted mempool cycle, with a new Private Relay sub-approach.

- fix(approach): review of [Private Transaction Broadcasting](approaches/approach-private-broadcasting.md), with a new Private Relay sub-approach ([#213](https://github.com/ethsystems/map/pull/213)).

Agreed, fixed.

Review of Private Transaction Broadcasting approach and related cards

0fec299

cygnusv requested review from oskarth and rymnc as code owners October 28, 2026 12:15

rymnc reviewed Oct 29, 2026

View reviewed changes

Address RFCs from ac

6d5bf17

oskarth reviewed Nov 4, 2026

View reviewed changes

Address RFCs from oskarth

63614e0

cygnusv requested review from oskarth and rymnc November 4, 2026 10:51

rymnc approved these changes Nov 6, 2026

View reviewed changes

	- Enshrinement: Shutter authored [EIP-8105](https://eips.ethereum.org/EIPS/eip-8105) (Draft), an enshrined encrypted mempool. Its bid to headline the Hegotá upgrade was withdrawn in February 2026 in favour of LUCID ([EIP-8184](https://eips.ethereum.org/EIPS/eip-8184)), which the team now supports for the upgrade after Hegotá.
	- Enshrinement: Shutter authored [EIP-8105](https://eips.ethereum.org/EIPS/eip-8105) (Draft), an enshrined encrypted mempool. Its bid to headline the Hegotá upgrade was withdrawn in February 2026 in favour of LUCID ([EIP-8184](https://eips.ethereum.org/EIPS/eip-8184)), which the team now supports.

	\| CROPS \| CR:low O:part P:part S:med \| CR:med O:y P:full S:med \| CR:med O:part P:part S:med \| CR:med O:part P:full S:med \|
	\| CROPS \| CR:low O:part P:part S:med \| CR:low O:y P:full S:med \| CR:med O:part P:part S:med \| CR:med O:part P:full S:med \|

	- Inclusion waits for a reached builder to win a slot; three builders produced about 88% of MEV-Boost blocks in late September 2026
	- Inclusion waits for a reached builder to win a slot; three builders produced over 90% of MEV-Boost blocks on each day from 22 to 30 September 2026 ([relayscan](https://www.relayscan.io/stats/day/2026-09-25))


		## [Unreleased]

		- fix(approach): Phase 1 review of [Private Transaction Broadcasting](approaches/approach-private-broadcasting.md) for the encrypted mempool cycle, with a new Private Relay sub-approach.

	- fix(approach): Phase 1 review of [Private Transaction Broadcasting](approaches/approach-private-broadcasting.md) for the encrypted mempool cycle, with a new Private Relay sub-approach.
	- fix(approach): review of [Private Transaction Broadcasting](approaches/approach-private-broadcasting.md), with a new Private Relay sub-approach ([#213](https://github.com/ethsystems/map/pull/213)).

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cygnusv commented Oct 28, 2026

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