Roles & access control

B20 is an ERC-20 superset with built-in role-based access control. Its role API uses familiar admin, grant, revoke, and renounce patterns, but B20 only enforces the built-in roles listed here.

Base roles

Role	Gates
`DEFAULT_ADMIN_ROLE`	Role grants/revokes, `setRoleAdmin`, `updatePolicy`, `updateSupplyCap`
`MINT_ROLE`	`mint`, `mintWithMemo`
`BURN_ROLE`	`burn`, `burnWithMemo`
`BURN_BLOCKED_ROLE`	Deprecated back-compat `burnBlocked` implementation only
`SEIZE_ROLE`	`seizeWithMemo`
`PAUSE_ROLE`	`pause`
`UNPAUSE_ROLE`	`unpause`
`METADATA_ROLE`	`updateName`, `updateSymbol`, `updateContractURI`
`OPERATOR_ROLE`	Asset-only multiplier and announcement operations

User-defined roles have no built-in enforcement. You can create them with setRoleAdmin and grant them with grantRole, but B20 token functions only check the built-in roles.

Admin renunciation

B20 has a specific last-admin rule. The last DEFAULT_ADMIN_ROLE holder cannot renounce or be revoked through normal role methods; those calls revert with LastAdminCannotRenounce. Use renounceLastAdmin() to permanently move the token to an admin-less state. A token can also launch admin-less by passing initialAdmin == address(0) at creation. After admin renunciation:

DEFAULT_ADMIN_ROLE-gated operations are permanently uncallable.
Existing operational role grants continue to work.
Admin resurrection is blocked; grantRole, revokeRole, and setRoleAdmin revert even through custom admin-role chains.

Pre-renunciation checklist

Configure every surviving operational path before renouncing the last admin.

IB20 token = IB20(tokenAddress);

// 1. Grant roles that must survive admin renunciation.
token.grantRole(B20Constants.MINT_ROLE, issuerOps);
token.grantRole(B20Constants.PAUSE_ROLE, incidentResponder);
token.grantRole(B20Constants.UNPAUSE_ROLE, governanceSafe);
token.grantRole(B20Constants.SEIZE_ROLE, complianceSafe);

// 2. Bind policies and supply cap while DEFAULT_ADMIN_ROLE still exists.
token.updatePolicy(B20Constants.MINT_RECEIVER_POLICY, mintAllowlistPolicyId);
token.updatePolicy(B20Constants.SEIZE_HOLDER_POLICY, seizeHolderPolicyId);
token.updateSupplyCap(1_000_000e18);

// 3. Permanently remove token administration.
token.renounceLastAdmin();

For an admin-less launch from creation, put the required grants and policy updates in initCalls, then set initialAdmin to address(0) in the create params.

Beryl Upgrade

Introduction

Core Concepts

Node Operators

Network Reference

API Reference

Protocol Specifications

Security

Base roles

Admin renunciation

Pre-renunciation checklist

Deployment & initCalls encoding

IB20 reference

​Base roles

​Admin renunciation

​Pre-renunciation checklist

Deployment & initCalls encoding

IB20 reference

Base roles

Admin renunciation

Pre-renunciation checklist