Impersonation

Neo3 uses CheckWitness and transaction signers/scopes, not Ethereum msg.sender.

Nanvil dev mode bypasses witness verification for impersonated accounts:

1. nanvil_impersonateAccount(address) registers a script hash
   
2. Transactions including that hash in signers pass CheckWitness without a valid signature
   
3. Transaction witness verification is skipped for impersonated signers
   

Example workflow

# Enable impersonation
curl ... -d '{"method":"nanvil_impersonateAccount","params":["NVTi..."]}'

# Build tx with impersonated address as signer (empty/minimal witness)
# Submit via sendrawtransaction

Auto mode

nanvil start --auto-impersonate or nanvil_autoImpersonateAccount(true) impersonates any signer.

On forked nodes, --auto-impersonate is enabled by default unless you pass --auto-impersonate=false.

Scopes

Use CalledByEntry or Global scopes when contracts check witness context. Multisig accounts may need explicit scope configuration.

Security

Impersonation is dev-only. Never enable on public networks.