Constants & addresses

Copy B20 precompile addresses, roles, policy scopes, variant bytes, policy IDs, and supply-cap constants.

Use StdPrecompiles.sol and B20Constants.sol from base-std as the canonical Solidity source. This page lists the same values for quick reference.

Precompile addresses

These addresses are identical on every network where B20 is active.

Surface	Address
B20 Factory	0xB20f000000000000000000000000000000000000
ActivationRegistry	0x8453000000000000000000000000000000000001
PolicyRegistry	0x8453000000000000000000000000000000000002

Roles

Role	Solidity constant
Default admin	bytes32(0)
Mint	keccak256("MINT_ROLE")
Burn	keccak256("BURN_ROLE")
Deprecated blocked burn	keccak256("BURN_BLOCKED_ROLE")
Seize	keccak256("SEIZE_ROLE")
Pause	keccak256("PAUSE_ROLE")
Unpause	keccak256("UNPAUSE_ROLE")
Metadata	keccak256("METADATA_ROLE")
Asset operator	keccak256("OPERATOR_ROLE")

Policy scopes

Scope	Solidity constant
Transfer sender	keccak256("TRANSFER_SENDER_POLICY")
Transfer receiver	keccak256("TRANSFER_RECEIVER_POLICY")
Transfer executor	keccak256("TRANSFER_EXECUTOR_POLICY")
Mint receiver	keccak256("MINT_RECEIVER_POLICY")
Seize holder	keccak256("SEIZE_HOLDER_POLICY")
Seize receiver	keccak256("SEIZE_RECEIVER_POLICY")

Policy IDs

Name	Value
ALWAYS_ALLOW	0
ALWAYS_BLOCK	(uint64(uint8(IPolicyRegistry.PolicyType.ALLOWLIST)) << 56) | 1

Custom policy IDs use this layout:

[8-bit PolicyType][56-bit counter]

Simple and composite policies share the same global counter. The counter starts at 2 because 0 and 1 are reserved for ALWAYS_ALLOW and ALWAYS_BLOCK.

Policy type bytes:

PolicyType	Byte
BLOCKLIST	0x00
ALLOWLIST	0x01
UNION	0x02
INTERSECT	0x03

UNION and INTERSECT are composite policy types. A UNION policy authorizes an account if any child policy authorizes it. An INTERSECT policy authorizes an account only if every child policy authorizes it. Each composite references two to four existing simple (ALLOWLIST or BLOCKLIST) policies. Composite policies cannot reference other composites.

A well-formed but never-created INTERSECT policy ID returns true for every account (vacuously authorized). Always call policyExists(policyId) before storing a composite policy ID; an invalid INTERSECT ID behaves like ALWAYS_ALLOW.

Variant bytes

Variant	Byte	Address shape
ASSET	0x00	0xB200...
STABLECOIN	0x01	0xB201...

Supply and decimals

Constant	Value
Minimum Asset decimals	6
Maximum Asset decimals	18
Maximum supply cap / no-cap sentinel	type(uint128).max
All features paused bitmask	15 (`TRANSFER	MINT	BURN	SEIZE`)

Imports

import {StdPrecompiles} from "base-std/StdPrecompiles.sol";
import {B20Constants} from "base-std/lib/B20Constants.sol";