Note: This feature is only available from version 1.10.0 of the Safe Multisig web interface.
Overview
Over the past two years, many applications have implemented off-chain signature flows enabling interaction without creating on-chain transactions or paying network fees. Our signed messages feature allows users to utilize this gasless signature flow with dApps compatible with EIP-1271 smart contract signatures.
What Is a Signature?
Each EOA has a private key that can sign messages. The resulting signature verifies both the integrity of the signed message and the account that signed it.
However, smart contracts like Safe Multisig have no private key. To create a signature via Safe Multisig, an on-chain signature transaction must be executed, or each owner must individually sign the same message and combine those signatures.
What Is a Signature Used For?
Signatures serve various purposes. Safe Multisig uses signatures to verify that owners have confirmed a transaction. dApps use signatures for authorization, ownership verification, DEX order confirmation, proposal voting, and more.
How Do I Create a Signed Message?
Signing into OpenSea, for example, opens a signing window. The initiator must keep this window open until sufficient signatures are collected. Signing with enough owner wallets verifies that you agree to the OpenSea login requirements. If your Safe Multisig has a 1/n policy, the signature becomes immediately valid.
The signed message is then added to your "Messages" in the "Transactions" section of the Safe Multisig UI.
Can I Still Sign On-Chain?
If the Safe App supports off-chain signatures, off-chain signing works by default. However, if you experience issues signing a message, you can revert to on-chain signatures. A toggle for this is found in the "Safe Apps" section of Safe Multisig "Settings." After enabling, signing from all Safe Apps occurs on-chain instead. Note that we cannot guarantee on-chain signature compatibility.
Signing with your wallet verifies that you agree to (in this case) the execution of the respective order. If your Safe Multisig has a 1/n policy, the order becomes immediately valid.