/// <reference types="node" />
import { Optional } from '@salesforce/ts-types';
/**
 * Returns the intended type of the object to return. This is implementation specific.
 *
 * @param buffer A buffer containing the decrypted secret.
 */
export declare type DecipherCallback<T> = (buffer: Buffer) => T;
/**
 * Used to store and retrieve a sensitive information in memory. This is not meant for at rest encryption.
 *
 * ```
 * const sString: SecureBuffer<string> = new SecureBuffer();
 * sString.consume(secretTextBuffer);
 * const value: string = sString.value((buffer: Buffer): string => {
 *     const password: string = buffer.toString('utf8');
 *     // doSomething with the password
 *     // returns something of type <T>
 *     return testReturnValue;
 * });
 * ```
 */
export declare class SecureBuffer<T> {
    private key;
    private iv;
    private secret?;
    /**
     * Invokes a callback with a decrypted version of the buffer.
     *
     * @param cb The callback containing the decrypted buffer parameter that returns a desired.
     * typed object. It's important to understand that once the callback goes out of scope the buffer parameters is
     * overwritten with random data. Do not make a copy of this buffer and persist it!
     */
    value(cb: DecipherCallback<T>): Optional<T>;
    /**
     * Overwrites the value of the encrypted secret with random data.
     */
    clear(): void;
    /**
     * Consumes a buffer of data that's intended to be secret.
     *
     * @param buffer Data to encrypt. The input buffer is overwritten with random data after it's encrypted
     * and assigned internally.
     */
    consume(buffer: Buffer): void;
}