import { SignatureProviderInterface, SignatureProviderInterfaceParams, SignatureProviderRequestEnvelope } from 'eosjs-signature-provider-interface';
export declare class SignatureProvider extends SignatureProviderInterface {
    private localStorage;
    private expiryMs;
    constructor(params: SignatureProviderInterfaceParams);
    protected sendRequest(requestEnvelope: SignatureProviderRequestEnvelope): void;
    getCachedKeys(): string[];
    setCachedKeys(keys: string[]): void;
    clearCachedKeys(): void;
    cleanUp(): void;
    private onWindowMessage;
}