/// <reference types="node" />
/**
 * Generate and encode a PreimageSha256 crypto-condition from a secret
 *
 * The function decodes the provided secret using utf8 and uses this as the preimage.
 *
 * @param secret the secret to use as a preimage
 */
export declare function preimageSha256(secret: string): {
    condition: Buffer;
    fulfillment: Buffer;
};