[dpkjnr]

What

Harden EVM TSS verification before the user key share signs, without adding validators for every intent.

• Reject definite mismatches for native, ERC-20, explicit-calldata, native-batch and token-batch payments. A caller-declared intent takes precedence; otherwise use the stored request intent. transfer and payment denote the same operation.
• Check supported consolidation shapes against the wallet base address, token identity when trusted metadata establishes it, canonical calldata and native value. Sweep amounts are not compared.
• Route legacy EVM signing preimages through serialized transaction verification and bind the verified bytes to the preimage; retain existing type-2 and specialized routes. Remove the remaining EvmCoin legacy verifier bypass.
• Reject unsupported EVM contractCall and customTx; warn precisely when trusted metadata or a complete intent validator is unavailable. Recognize FLR atomic formats without treating them as ordinary EVM transactions.
• Add the deployed Katana batcher address to mainnet and Bokuto SDK network statics. This does not enable Katana ERC-20 batching.

Verification

• Node 24.22.1: forced TypeScript build of statics, sdk-core, abstract-eth, sdk-coin-evm, sdk-coin-eth, sdk-coin-bsc and sdk-coin-flr.
• Unit suites: abstract-eth 270; sdk-coin-eth 569; sdk-coin-evm 69; sdk-coin-bsc 58; sdk-coin-xdc 65; FLR 65; focused sdk-core 72. Statics network and coin tests: 41,790.
• Real ECDSA and MPCv2 signing entry points: matching transactions reach the signing-round boundary; mismatches and serialized/preimage inconsistencies do not. Tests cover type-0 on EIP-1559-capable chains, type-2, BSC, and legacy-only EVM chains.
• Offline replay through real signing entry points: 138 delivered payment requests across 30 coin types, plus all seven delivered EVM TSS consolidation requests in the window. All passed without warnings; synthetic destination, amount and token-identity mismatches were rejected. The query uses source creation DATE, 2026-08-07 inclusive through 2026-11-05 exclusive, TSS-wallet filtering and request deduplication. No keys or network calls were used. Temporary production payloads were removed.

Limits and release gates

• The 138-payment replay is a bounded sample, not the full production population; the release gate remains open. Consolidation evidence covers seven requests on ETH/MPCv2 only.
• Missing asset/batcher metadata and intents without a complete validator remain warning-only. Encrypted confidential-token amounts are not compared. No universal fail-closed claim or INFOSEC-671 closure is made.
• FLR atomic exports/imports are recognized and warned, not verified against intent. On the prehashed MPCv2 path the recognized serialized bytes are not currently bound to the signed digest; this pre-existing gap remains open.
• Current upstream does not expose the reference branch's client-side strict warning option; this PR does not introduce a new strict-mode API.
• CI and Security review are pending.

Ticket: CECHO-2460

[linear-code]

CECHO-2460

[github-actions]

⚠️ Compatibility checks are failing on Node.js 27-nightly (experimental, non-blocking). This does not block merge, but it signals an incompatibility to fix before this release becomes supported.

View run

[dpkjnr]

Closing in favour of the narrower first release in #10136, which limits the change to verifyTssTransaction.

The remaining work in this PR is now tracked as separate tickets: CECHO-2680 (contractCall / customTx) and the sub-tickets under CECHO-2679 (legacy routing, intent plumbing, Katana, FLR, remaining handlers).

The branch is kept for reference.