How can my EVM contract look up associated addresses or trigger address association?

Sei provides an Address Precompile at 0x0000000000000000000000000000000000001004 specifically for managing the link between Sei Native (sei1...) and EVM (0x...) addresses derived from the same private key.

Key Functions (Solidity Interface):

interface ISeiAddressPrecompile {
    // --- View Functions --- 

    /**
     * @notice Gets the associated Sei Bech32 address for a given EVM address.
     * @param evmAddr The EVM address (`0x...`) to look up.
     * @return seiAddr The associated Sei address string (`sei1...`). Reverts if not associated.
     */
    function getSeiAddr(address evmAddr) external view returns (string memory seiAddr);

    /**
     * @notice Gets the associated EVM address for a given Sei Bech32 address.
     * @param seiAddr The Sei address string (`sei1...`) to look up.
     * @return evmAddr The associated EVM address (`0x...`). Reverts if not associated.
     */
    function getEvmAddr(string memory seiAddr) external view returns (address evmAddr);

    // --- State Changing Functions --- 

    /**
     * @notice Associates the EVM and Sei addresses derived from the signer of the provided message.
     * @dev Requires a signature created off-chain over the customMessage.
     * @param v The recovery ID (usually 27 or 28, potentially as hex string "0x1b" or "0x1c").
     * @param r The R component of the ECDSA signature (as hex string).
     * @param s The S component of the ECDSA signature (as hex string).
     * @param customMessage The exact message string that was signed.
     * @return seiAddr The associated Sei address.
     * @return evmAddr The associated EVM address.
     */
    function associate(string memory v, string memory r, string memory s, string memory customMessage) external returns (string memory seiAddr, address evmAddr);

    /**
     * @notice Associates the EVM and Sei addresses derived from a provided public key.
     * @dev The public key must be in compressed format, represented as a hex string without the "0x" prefix.
     * @param pubKeyHex The compressed public key hex string.
     * @return seiAddr The associated Sei address.
     * @return evmAddr The associated EVM address.
     */
    function associatePubKey(string memory pubKeyHex) external returns (string memory seiAddr, address evmAddr);
}

How to Use:

• Lookups (getSeiAddr, getEvmAddr): Call these view functions directly from your contract to find an existing association. Handle potential reverts if no association exists (e.g., using try/catch).
• Association (associate, associatePubKey): These functions create the on-chain link. They are typically not called directly by end-users from a generic contract.
  • The associate function requires an off-chain signature generated by the user's wallet, making it suitable for integration into dApp frontends or dedicated association tools.
  • The associatePubKey function requires the user's compressed public key, which might be less common for users to handle directly.
  • These functions will fail if an association already exists for the derived addresses.

Important Considerations:

• Association Requirement: Many other Sei precompiles (like Staking, IBC, Bank send) require the caller to be associated before they can be used successfully.
• Gas Costs: Lookup functions are cheap. Association functions (associate, associatePubKey) have a higher base gas cost (e.g., 50,000) due to cryptographic operations.
• Security: Association proves ownership. The associate function relies on cryptographic signatures for security.