/**
 * Blind Index Generation (WASM-backed)
 *
 * Thin wrappers over `@totalreclaw/core` WASM module for SHA-256 blind
 * indices with Porter stemming. The `generateTrapdoors` and utility
 * functions remain in TypeScript as they compose on top of the WASM
 * blind index output.
 *
 * Matches mcp/src/subgraph/crypto.ts:generateBlindIndices() exactly.
 */
/**
 * Tokenize text into words for blind indexing.
 *
 * Performs basic tokenization:
 * - Converts to lowercase
 * - Removes punctuation (keeps Unicode letters, numbers, whitespace)
 * - Splits on whitespace
 * - Filters out short tokens (< 2 chars)
 *
 * Note: This TS tokenizer is kept for callers that need raw tokens
 * (e.g., BM25 scoring). The WASM module has its own tokenizer used
 * internally by generateBlindIndices().
 *
 * @param text - Text to tokenize
 * @returns Array of tokens
 */
export declare function tokenize(text: string): string[];
/**
 * Compute SHA-256 hash of a string.
 *
 * Uses Node.js crypto for callers that need ad-hoc hashing outside of
 * the blind index pipeline.
 *
 * @param input - String to hash
 * @returns Hex-encoded SHA-256 hash
 */
export declare function sha256Hash(input: string): string;
/**
 * Generate blind indices from text.
 *
 * Delegates to the WASM module which performs tokenization, Porter
 * stemming, and SHA-256 hashing. Stemmed tokens are prefixed with
 * "stem:" before hashing to avoid collisions.
 *
 * Matches mcp/src/subgraph/crypto.ts:generateBlindIndices().
 *
 * @param text - Document text
 * @returns Array of blind indices (hex-encoded SHA-256 hashes), deduplicated
 */
export declare function generateBlindIndices(text: string): string[];
/**
 * Generate trapdoors for search query.
 *
 * Trapdoors are SHA-256 hashes of:
 * 1. All tokens in the query (for keyword matching)
 * 2. Stemmed variants of tokens (for morphological matching)
 * 3. All LSH bucket identifiers from query embedding (for semantic matching)
 *
 * @param query - Search query text
 * @param lshBuckets - LSH bucket identifiers from query embedding (already blind-hashed)
 * @returns Array of trapdoors (hex-encoded SHA-256 hashes)
 */
export declare function generateTrapdoors(query: string, lshBuckets: string[]): string[];
/**
 * Generate only token-based blind indices (without LSH).
 *
 * Useful for keyword-only search or when embedding is not available.
 *
 * @param text - Text to index
 * @returns Array of blind indices for tokens only
 */
export declare function generateTokenIndices(text: string): string[];
/**
 * Verify that a blind index matches a trapdoor.
 *
 * Since both are SHA-256 hashes, this is a simple equality check.
 */
export declare function verifyBlindIndexMatch(blindIndex: string, trapdoor: string): boolean;
/**
 * Compute the overlap between two sets of blind indices.
 *
 * Used to estimate recall quality during development.
 */
export declare function computeIndexOverlap(indices1: string[], indices2: string[]): number;
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