Constants & Addresses

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")`

SEIZE_HOLDER_POLICY uses inverted authorization semantics: a from account is seizable only when isAuthorized(policyId, from) returns false. This is the opposite of transfer-style allowlist gating. An unset slot reads as 0 (ALWAYS_ALLOW), so no account is seizable until an issuer explicitly configures the slot.

Policy IDs

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

Custom policy IDs use this layout:

Policy ID Layout

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

Policy type bytes:

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

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

Solidity Imports

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

Specifications

Reference

Node Operators

Security

Precompile Addresses

Roles

Policy Scopes

Policy IDs

Variant Bytes

Supply and Decimals

Imports

​Precompile Addresses

​Roles

​Policy Scopes

​Policy IDs

​Variant Bytes

​Supply and Decimals

​Imports

Precompile Addresses

Roles

Policy Scopes

Policy IDs

Variant Bytes

Supply and Decimals

Imports