/**
 * SHA-256 that can be fed in pieces, as `createHash('sha256')` is, with the same digest. Strings are
 * hashed as UTF-8. Synchronous, unlike Web Crypto's `digest()`, so a cache key can be computed where
 * it is needed.
 */
export declare class Sha256 {
    private readonly state;
    private readonly block;
    private readonly words;
    private filled;
    private total;
    /** Adds data: a string, as UTF-8, or bytes. */
    update(data: string | Uint8Array): this;
    /** The digest as lowercase hex. The hash takes no more data afterwards. */
    digest(): string;
    private compress;
}
/**
 * The SHA-256 digest of a string, as UTF-8, or of bytes, as lowercase hex. Native where the runtime
 * has it, which is ten times faster on large inputs, and the same digest everywhere else.
 */
export declare function sha256Hex(data: string | Uint8Array): string;
/** A SHA-256 fed in pieces, as a stream's bytes arrive. */
export interface IncrementalSha256 {
    /** Adds bytes. */
    update(data: Uint8Array): unknown;
    /** The digest so far, as lowercase hex. Call once, at the end. */
    digest(): string;
}
/** A SHA-256 to feed in pieces: native where the runtime has it, and the same digest everywhere else. */
export declare function createSha256(): IncrementalSha256;