/**
 * Simple keyring for managing a single account from a private key.
 * Used for importing existing accounts that are not derived from a mnemonic.
 */
export declare class SimpleKeyring {
    readonly type = "Simple";
    private privateKey;
    address: string;
    /**
     * Creates a new SimpleKeyring instance from a private key.
     * @param privateKey - The private key to import (hex string without '0x' prefix)
     */
    constructor(privateKey: string);
    /**
     * Returns the private key. This should be used with extreme caution.
     * @returns The private key as a hex string
     */
    getPrivateKey(): string;
    /**
     * Serializes the keyring into a plain object for encryption and storage.
     * @returns An object containing the keyring type and private key
     */
    serialize(): any;
    /**
     * Deserializes a plain object back into a SimpleKeyring instance.
     * @param data - The serialized keyring data
     * @returns A new SimpleKeyring instance
     * @throws Error if the data is invalid or missing required fields
     */
    static deserialize(data: any): SimpleKeyring;
}