/**
 * Message signing and verification for EVM (EIP-191) and UTXO (Bitcoin-style)
 * networks.
 */
/**
 * Signs a message using EIP-191 personal sign (the same scheme as MetaMask's
 * `personal_sign`).
 *
 * @param message - The message to sign (string or raw bytes).
 * @param privateKey - The 32-byte private key.
 * @returns The 65-byte signature as a hex string with `0x` prefix.
 */
export declare function signEvmMessage(message: string | Uint8Array, privateKey: Uint8Array): string;
/**
 * Verifies an EIP-191 personal sign signature.
 *
 * @param message - The original message (string or raw bytes).
 * @param signature - The signature (hex string with `0x` prefix).
 * @param address - The expected signer address (EIP-55 checksummed or lowercase).
 * @returns `true` if the signature is valid and was produced by the given address.
 */
export declare function verifyEvmMessage(message: string | Uint8Array, signature: string, address: string): boolean;
/**
 * Signs a message using the Bitcoin message signing standard.
 *
 * @param message - The message to sign (string or raw bytes).
 * @param privateKey - The 32-byte private key.
 * @param prefix - The chain-specific sign header. Defaults to Bitcoin's prefix.
 * @returns The signature as a base64 string (65 bytes).
 */
export declare function signUtxoMessage(message: Uint8Array | string, privateKey: Uint8Array, prefix?: string): string;
/**
 * Recovers the compressed public key from a Bitcoin-style signed message.
 *
 * @param message - The original message.
 * @param signature - The base64-encoded signature (65 bytes).
 * @param prefix - The chain-specific sign header.
 * @returns The recovered compressed public key (33 bytes).
 */
export declare function recoverUtxoPublicKey(message: Uint8Array | string, signature: string, prefix?: string): Uint8Array;