Signer Rotation Runbook
Engineer/DeveloperSecurity SpecialistMultisig Security
This is an example runbook. Review and customize it for your protocol before use. Add your specific multisig addresses, signer requirements, and communication channels.
Quick Reference
| Field | Value |
|---|---|
| Typical Severity | Routine |
| Required Threshold | Standard |
| Owner | Multisig Admin |
| Last Updated | Date |
When to Use
- Adding a new signer
- Removing a departing signer
- Replacing a signer (key rotation, lost access)
Prerequisites
- Reason for change documented
- New signer has completed Joining a Multisig (if new)
- New signer's address verified via signed message
- Change maintains minimum signer count and threshold requirements
- If reducing signers or threshold: justification documented and approved
Adding a Signer
EVM (Safe)
Proposer:
- Go to Safe
- Settings > Setup > Owners
- Click "Add new owner"
- Enter new signer's address (checksummed)
- Set threshold (typically maintain same ratio)
- Create transaction
Verification checklist:
[ ] New signer address is correct (verified via signed message)
[ ] Threshold is appropriate after addition
[ ] Not accidentally removing anyone
[ ] Message hash matches hardware walletSolana (Squads)
Proposer:
- Go to Squads Multisig
- Configuration > Add Member
- Enter new signer's address
- Set permissions
- Create proposal
Removing a Signer
EVM (Safe)
Proposer:
- Settings > Setup > Owners
- Click remove (trash icon) next to signer
- Adjust threshold if needed (cannot exceed new signer count)
- Create transaction
Verification checklist:
[ ] Correct signer being removed
[ ] Threshold still appropriate (>=50%)
[ ] Maintains minimum signer count (3+)
[ ] Message hash matches hardware walletSolana (Squads)
Proposer:
- Configuration > Remove Member
- Select member to remove
- Adjust threshold if needed
- Create proposal
Replacing a Signer (Swap)
When a signer needs to change their address.
If Original Key is Accessible
-
New signer proves ownership by signing message with existing address:
[Handle] is rotating to new address [0xNEW...] for [Multisig Name] -
New signer completes Joining a Multisig with the new address
-
Create transaction to add new address
-
After execution, create transaction to remove old address
If Original Key is Lost
- Signer verifies identity through alternative methods:
- Video call with other signers
- Authentication via verified social media
- Other pre-established verification
- Document verification in transaction notes
- New signer completes onboarding
- Create transaction to add new and remove old (can be batch)
Batch Add + Remove
Can combine add and remove in a single transaction:
EVM (Safe):
- Use Transaction Builder or batch transaction
- Add
addOwnerWithThresholdcall - Add
removeOwnercall - Execute as a single transaction
Benefits: Atomic operation, no intermediate state with wrong threshold.
Post-Transaction
After execution:
- Update registration or internal documentation with the new signer list
- Update communication channel membership
- Removed signer leaves communication channels
- Test that the new signer can successfully sign a test transaction
Offboarding Checklist
When removing a signer:
- Signer removed from multisig on-chain
- Signer removed from communication channels
- Documentation updated
- Signer deleted local sensitive information
- Any shared credentials rotated (if applicable)
Timeline requirements:
- Emergency-class multisigs: 48-72 hours
- Critical-class: 7 days
- Others: 14 days