feat: add Ethereum MPC keyring

[matthiasgeihs]

Summary

• Add @metamask/eth-mpc-keyring: a 2-party client/server MPC keyring with DKLS23 TSS, cloud backup sync, and vendored MFA wallet libs
• Support create/import init, key-share rotate/check/sync, and signing (transactions, personal_sign, typed data, EIP-7702 authorizations)
• Replaces the earlier WIP in feat: add MPC keyring #440 with a cleaned history rebased on main

Test plan

• yarn workspace @metamask/eth-mpc-keyring test
• yarn workspace @metamask/eth-mpc-keyring build
• Smoke-check create/import and signing against a staging cloud/relayer if available

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[matthiasgeihs]

Replaces #440 with a cleaned history rebased onto main.

[socket-security]

Review the following changes in direct dependencies. Learn more about Socket for GitHub.

Diff	Package	Supply Chain Security	Vulnerability	Quality	Maintenance	License
	@​metamask/​mfa-wallet-util@​0.0.0
	@​metamask/​mfa-wallet-interface@​0.0.0
	@​metamask/​mfa-wallet-cl24-lib@​0.0.0
	@​metamask/​mfa-wallet-dkls23-lib@​0.0.0	N/A	N/A	N/A	N/A	N/A
	@​metamask/​mfa-wallet-e2ee@​0.0.0
	@​metamask/​mfa-wallet-network@​0.0.0

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[socket-security]

Warning

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  @SocketSecurity ignore npm/PACKAGE@VERSION

Action	Severity	Alert  (click "▶" to expand/collapse)
Warn		Network access: npm centrifuge in module globalThis["fetch"] Module: globalThis["fetch"] Location: Package overview From: packages/keyring-eth-mpc/package.json → npm/@metamask/mfa-wallet-network@0.0.0 → npm/centrifuge@5.7.2 ℹ Read more on: This package | This alert | What is network access? Next steps: Take a moment to review the security alert above. Review the linked package source code to understand the potential risk. Ensure the package is not malicious before proceeding. If you're unsure how to proceed, reach out to your security team or ask the Socket team for help at support@socket.dev. Suggestion: Packages should remove all network access that is functionally unnecessary. Consumers should audit network access to ensure legitimate use. Mark the package as acceptable risk. To ignore this alert only in this pull request, reply with the comment @SocketSecurity ignore npm/centrifuge@5.7.2. You can also ignore all packages with @SocketSecurity ignore-all. To ignore an alert for all future pull requests, use Socket's Dashboard to change the triage state of this alert.
Warn		Potential code anomaly (AI signal): npm @protobufjs/codegen is 72.0% likely to have a medium risk anomaly Notes: No direct malicious behavior (e.g., exfiltration, persistence, or credential theft) is evident in this module. However, it is inherently a dynamic code execution utility: it constructs JavaScript source from caller-influenced templates/body and scope, then executes it using the Function constructor. If any upstream input can influence templates or accumulated body, this module can enable code injection/RCE in the caller’s context. Treat as high-risk when used with untrusted data; otherwise it functions as a formatter/codegen helper. Confidence: 0.72 Severity: 0.52 From: packages/keyring-eth-mpc/package.json → npm/@metamask/mfa-wallet-network@0.0.0 → npm/@trezor/connect-web@9.6.1 → npm/@protobufjs/codegen@2.0.5 ℹ Read more on: This package | This alert | What is an AI-detected potential code anomaly? Next steps: Take a moment to review the security alert above. Review the linked package source code to understand the potential risk. Ensure the package is not malicious before proceeding. If you're unsure how to proceed, reach out to your security team or ask the Socket team for help at support@socket.dev. Suggestion: An AI system found a low-risk anomaly in this package. It may still be fine to use, but you should check that it is safe before proceeding. Mark the package as acceptable risk. To ignore this alert only in this pull request, reply with the comment @SocketSecurity ignore npm/@protobufjs/codegen@2.0.5. You can also ignore all packages with @SocketSecurity ignore-all. To ignore an alert for all future pull requests, use Socket's Dashboard to change the triage state of this alert.
Warn		Potential code anomaly (AI signal): npm protobufjs is 61.0% likely to have a medium risk anomaly Notes: The analyzed code segment is a standard RPC service wrapper (protobufjs style) with conventional input validation, encoding/decoding, event emission, and end handling. No malicious behavior is evident, and there are no observable security vulnerabilities beyond ordinary library-level error handling. It does not exhibit data exfiltration, backdoors, or other anti-security patterns. Confidence: 0.61 Severity: 0.55 From: packages/keyring-eth-mpc/package.json → npm/@metamask/mfa-wallet-network@0.0.0 → npm/protobufjs@7.6.6 ℹ Read more on: This package | This alert | What is an AI-detected potential code anomaly? Next steps: Take a moment to review the security alert above. Review the linked package source code to understand the potential risk. Ensure the package is not malicious before proceeding. If you're unsure how to proceed, reach out to your security team or ask the Socket team for help at support@socket.dev. Suggestion: An AI system found a low-risk anomaly in this package. It may still be fine to use, but you should check that it is safe before proceeding. Mark the package as acceptable risk. To ignore this alert only in this pull request, reply with the comment @SocketSecurity ignore npm/protobufjs@7.6.6. You can also ignore all packages with @SocketSecurity ignore-all. To ignore an alert for all future pull requests, use Socket's Dashboard to change the triage state of this alert.

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[cursor]

Cursor Bugbot has reviewed your changes and found 4 potential issues.

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^{Reviewed by Cursor Bugbot for commit 1027e20. Configure here.}

[cursor]

Sign overwrites concurrent key updates

High Severity

#signHash snapshots #state and later writes that snapshot back with #applyKeyState. rotateKeyShares and syncKeyShare are not on #signQueue, so a rotation or sync that finishes during signing is overwritten with the stale keyShare and backupId, desynchronizing the client from the server.

Additional Locations (2)

• packages/keyring-eth-mpc/src/mpc-keyring.ts#L248-L292
• packages/keyring-eth-mpc/src/mpc-keyring.ts#L313-L326

 

^{Reviewed by Cursor Bugbot for commit 1027e20. Configure here.}

[cursor]

Rotation can desynchronize key shares

High Severity

rotateKeyShares commits the new server share in the MPC session before the client persists that share. If storeKeyShareBackup fails afterward, #state still holds the old share while the server has the new one, and neither a retry nor syncKeyShare can repair the mismatch.

 

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[cursor]

Risk: high. Not approved — this adds a new Ethereum MPC keyring with TSS signing, cloud backup, and vendored MFA libraries, which is above the low-risk approval threshold. Human review is needed.

  

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