/**
 * Noah — SHA-256 Hash Chain
 *
 * Provides cryptographic integrity verification for temporal records.
 * Each record's hash includes the previous record's hash, forming
 * an immutable chain. Patent reference: Temporal Ethical Guidance §7.
 */
/**
 * Compute a SHA-256 hash of the given data string.
 */
export declare function sha256(data: string): string;
/**
 * Compute the hash for a temporal assessment record.
 * The hash covers all meaningful fields plus the previous hash,
 * creating an immutable chain.
 */
export declare function computeRecordHash(record: Record<string, unknown>, previousHash: string): string;
/**
 * Verify the integrity of a hash chain.
 * Returns { valid: true } if the chain is intact,
 * or { valid: false, brokenAt } with the index of the first broken link.
 */
export declare function verifyHashChain(records: Array<{
    cryptographicHash: string;
    previousHash: string;
} & Record<string, unknown>>): {
    valid: boolean;
    brokenAt?: number;
};
/**
 * The genesis previousHash — SHA-256 of empty string.
 * Used as the previousHash for the very first record in a chain.
 */
export declare const GENESIS_HASH: string;
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