/**
 * HD (Hierarchical Deterministic) keyring for managing multiple accounts
 * derived from a single mnemonic phrase using BIP-44 derivation paths.
 * Supports EVM-compatible chains.
 */
export declare class HDKeyring {
    readonly type = "HD";
    private mnemonic;
    private seed;
    private static seedCache;
    accounts: string[];
    /**
     * Creates a new HDKeyring instance from a mnemonic phrase.
     * @param mnemonic - The mnemonic phrase (12, 15, 18, 21, or 24 words)
     * @throws Error if the mnemonic is invalid
     */
    constructor(mnemonic: string);
    /**
     * Initializes the keyring by generating the seed and creating the first account.
     * This method must be called before using the keyring.
     * @returns Promise that resolves when initialization is complete
     * @throws Error if seed generation or account derivation fails
     */
    initialize(): Promise<void>;
    /**
     * Derives an account at a specific index using BIP-44 derivation.
     * @param index - The account index to derive (0-based)
     * @returns Promise resolving to an object containing the derived address and private key
     * @throws Error if the keyring is not initialized or derivation fails
     */
    private deriveAccount;
    /**
     * Adds a new account derived from the mnemonic at the next available index.
     * @returns Promise resolving to the address of the newly created account
     * @throws Error if account derivation fails or duplicate address is generated
     */
    addNewAccount(): Promise<string>;
    /**
     * Gets the private key for a given address managed by this keyring.
     * @param address - The account address to get the private key for
     * @returns Promise resolving to the private key as a hex string
     * @throws Error if the address is not found in this keyring
     */
    getPrivateKeyForAddress(address: string): Promise<string>;
    /**
     * Returns the mnemonic phrase. USE WITH CAUTION - this exposes sensitive data.
     * @returns The mnemonic phrase as a string
     */
    getMnemonic(): string;
    /**
     * Serializes the keyring data for encryption and storage.
     * @returns An object containing the keyring type, mnemonic, and account addresses
     */
    serialize(): any;
    /**
     * Deserializes data into an HDKeyring instance.
     * @param data - The serialized keyring data
     * @returns Promise resolving to a new HDKeyring instance
     * @throws Error if the data is invalid or missing required fields
     */
    static deserialize(data: any): Promise<HDKeyring>;
    /**
     * Clears the seed cache to free up memory.
     * Call this when you want to clear sensitive data from memory.
     */
    static clearSeedCache(): void;
    /**
     * Gets the cache size for debugging purposes.
     * @returns Number of cached seeds
     */
    static getSeedCacheSize(): number;
}