/**
 * Hash Utilities Module
 *
 * Provides SHA256 hashing utilities for:
 * - String content hashing (fingerprinting)
 * - File content hashing (delta detection)
 * - Project path hashing (index directory names)
 */
/**
 * Compute SHA256 hash of a string
 *
 * @param input - The string to hash
 * @returns Full SHA256 hex digest (64 characters)
 *
 * @example
 * ```typescript
 * hashString('hello world')
 * // => 'b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9'
 * ```
 */
export declare function hashString(input: string): string;
/**
 * Compute SHA256 hash of a file's content using streaming
 *
 * Uses streaming to handle large files without loading entire content into memory.
 * Falls back to synchronous read for small files for better performance.
 *
 * @param filePath - Absolute path to the file
 * @returns Promise resolving to SHA256 hex digest (64 characters)
 * @throws MCPError with FILE_NOT_FOUND if file doesn't exist
 * @throws MCPError with PERMISSION_DENIED if file can't be read
 *
 * @example
 * ```typescript
 * const hash = await hashFile('/path/to/file.ts');
 * // => 'a94a8fe5ccb19ba61c4c0873d391e987982fbbd3...'
 * ```
 */
export declare function hashFile(filePath: string): Promise<string>;
/**
 * Hash length constants for project path hashing
 *
 * SMCP-057: Increased from 16 to 32 characters for better collision resistance
 * - OLD_HASH_LENGTH (16 chars) = 64 bits of entropy
 * - NEW_HASH_LENGTH (32 chars) = 128 bits of entropy (recommended minimum for security)
 */
export declare const OLD_HASH_LENGTH = 16;
export declare const NEW_HASH_LENGTH = 32;
/**
 * Compute SHA256 hash of a project path for index directory naming
 *
 * SMCP-057: Returns a truncated hash (first 32 characters) suitable for directory names.
 * This provides 128 bits of entropy, which is the recommended minimum for security-sensitive
 * applications. Previously used 16 characters (64 bits).
 *
 * The path is normalized before hashing:
 * - Resolved to absolute path
 * - Lowercase on Windows for case-insensitivity
 * - Forward slashes normalized
 *
 * @param projectPath - Path to the project root
 * @returns First 32 characters of SHA256 hex digest
 *
 * @example
 * ```typescript
 * hashProjectPath('/Users/dev/my-project')
 * // => 'a1b2c3d4e5f6789001234567890abcde'
 *
 * // On Windows, paths are normalized:
 * hashProjectPath('C:\\Users\\Dev\\My-Project')
 * // Same as hashProjectPath('c:/users/dev/my-project')
 * ```
 */
export declare function hashProjectPath(projectPath: string): string;
/**
 * SMCP-057: Compute legacy (16-char) hash for backward compatibility
 *
 * Used during migration to support indexes created with the old hash format.
 * Should only be used for migration/compatibility checks.
 *
 * @param projectPath - Path to the project root
 * @returns First 16 characters of SHA256 hex digest (legacy format)
 */
export declare function hashProjectPathLegacy(projectPath: string): string;
/**
 * Compute SHA256 hash synchronously for a file
 *
 * Use this only when async is not possible (e.g., in certain callback contexts).
 * Prefer hashFile for normal operations.
 *
 * @param filePath - Absolute path to the file
 * @returns SHA256 hex digest (64 characters)
 * @throws MCPError with FILE_NOT_FOUND if file doesn't exist
 */
export declare function hashFileSync(filePath: string): string;
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