bech32

Bech32 Precompile

Address

0x0000000000000000000000000000000000000400

Description

The Bech32 precompile provides address format conversion between Ethereum hex addresses and Cosmos bech32 addresses. This enables smart contracts to interact with Cosmos SDK modules that require bech32-formatted addresses.

Interface

Methods

hexToBech32

function hexToBech32(
    address addr,
    string memory prefix
) external returns (string memory bech32Address);

Converts an Ethereum hex address to bech32 format with the specified human-readable prefix (HRP).

Parameters:

• addr: The Ethereum address to convert
• prefix: The bech32 human-readable prefix (e.g., "cosmos", "evmos")

Returns:

• Bech32-formatted address string

Validation:

• Prefix must be non-empty and properly formatted
• Address must be a valid 20-byte Ethereum address
• Reverts if bech32 encoding fails

bech32ToHex

function bech32ToHex(
    string memory bech32Address
) external returns (address addr);

Converts a bech32-formatted address to Ethereum hex format.

Parameters:

• bech32Address: The bech32 address string to convert

Returns:

• Ethereum address in hex format

Validation:

• Input must be a valid bech32 address with proper formatting
• Address must contain the separator character "1"
• The decoded address must be 20 bytes
• Reverts if bech32 decoding fails

Implementation Details

Gas Usage

The precompile uses a configurable base gas amount for all operations. The gas cost is fixed regardless of string length within reasonable bounds.

Address Validation

Both methods perform validation on the address format:

• Hex addresses must be exactly 20 bytes
• Bech32 addresses must conform to the bech32 specification
• Invalid addresses result in execution reversion

Prefix Handling

For hexToBech32:

• The prefix parameter determines the human-readable part of the bech32 address
• Common prefixes include account addresses, validator addresses, and consensus addresses
• Empty or whitespace-only prefixes are rejected

For bech32ToHex:

• The prefix is automatically extracted from the bech32 address
• No prefix parameter is required as it's embedded in the address

State Mutability

Both methods are marked as nonpayable in the ABI but function as read-only operations. They do not modify blockchain state and could technically be seen as view functions.