Summary

Solana wallet stakeholders met to align on a path to ship off-chain message signing across the ecosystem. The goal was to agree on a concrete implementation pathway for the existing OCMS standard.

• Participants: Solana Foundation, Phantom, Solflare, Jupiter, Ledger, Trezor, Anza, OS Contributors for Supabase & others.
• Headline decision: We will introduce a new signOffChainMessage method (rather than changing the existing signMessage/solanaSignMessage), supporting the v1 standard only. This is a non-breaking, additive change that lets wallets and dApps adopt at their own pace.

Proposal Considered

RFC: Add solana:signOffchainMessage feature for off-chain message signing

Key Decisions

Close existing Wallet Adapter PR#1097 in lieu of the following:

1. New method, no breaking changes
   • Add a new signOffChainMessage method instead of extending the existing solanaSignMessage.
   • Maintains backward compatibility for existing dApps and avoids breaking changes across the ecosystem.
   • Enables gradual, opt-in adoption by dApps.
2. Wallet owns serialization
   • The wallet/signer — the most trusted layer — owns message envelope construction.
   • dApps send the raw message content; the wallet wraps it with the proper preamble/envelope before signing.
   • The method returns both the signature and the signed message object.
   • Follows EVM precedent, where the wallet is the trust authority.
   • Keeps a simple window.signMessage-style interface and avoids pushing dependencies into auth libraries, reducing the security attack surface.
3. v1 only — drop v0
   • Support the v1 codec only; v0 support is dropped.
   • v0 has minimal adoption
   • A new method gives us a clean break from the legacy approach.