/**
 * Platform-agnostic crypto utilities for browser and Node.js environments.
 *
 * This module provides cryptographic functions that work in both browser and Node.js
 * environments, abstracting away the differences between Web Crypto API and Node.js crypto.
 *
 * **Platform Detection Boundary:**
 * This file uses `isBrowserEnvironment()` and `isNodeEnvironment()` to detect the
 * runtime platform and conditionally load the appropriate crypto implementation:
 * - Browser: uses `window.crypto.getRandomValues()` (Web Crypto API)
 * - Node.js: uses `require('crypto').randomBytes` (loaded lazily via `require()`)
 *
 * The Node.js `crypto` module is never imported at the top level; it is loaded
 * dynamically inside `getRandomBytes()` only when `isBrowserEnvironment()` returns
 * false. This ensures the module can be bundled for browsers without triggering
 * missing-module errors.
 *
 * SHA-1 hashing uses `@noble/hashes/sha1`, which is a pure-JS implementation
 * that works identically in both environments — no platform branching needed.
 *
 * @platform Node.js (conditional — `getRandomBytes` falls back to Node.js `crypto` when not in a browser)
 * @module platformCrypto
 * @see Requirements 11.1, 11.2, 11.3, 11.4, 11.5
 * @see Requirement 18.4 — platform-specific code isolated behind detection boundary
 */
/**
 * Interface for platform-agnostic crypto operations.
 */
export interface IPlatformCrypto {
    /**
     * Generate cryptographically secure random bytes.
     * @param length - Number of bytes to generate
     * @returns Uint8Array of random bytes
     */
    randomBytes(length: number): Uint8Array;
    /**
     * Compute SHA-1 hash of input data.
     * @param data - String or Uint8Array to hash
     * @returns Uint8Array containing the hash
     */
    sha1(data: string | Uint8Array): Uint8Array;
}
/**
 * Detects whether the code is running in a browser environment.
 *
 * @returns true if running in a browser with Web Crypto API available
 * @see Requirement 11.5
 */
export declare function isBrowserEnvironment(): boolean;
/**
 * Detects whether the code is running in a Node.js environment.
 *
 * @returns true if running in Node.js
 * @see Requirement 11.5
 */
export declare function isNodeEnvironment(): boolean;
/**
 * Generate cryptographically secure random bytes.
 *
 * Uses Web Crypto API (crypto.getRandomValues) in browser environments
 * and Node.js crypto.randomBytes in Node.js environments.
 *
 * Handles the Web Crypto API limit of 65,536 bytes per call by chunking
 * large requests.
 *
 * @param length - Number of bytes to generate (must be non-negative)
 * @returns Uint8Array of cryptographically secure random bytes
 * @throws Error if length is negative
 * @see Requirements 11.1, 11.2, 11.3
 *
 * @example
 * ```typescript
 * const bytes = getRandomBytes(32);
 * console.log(bytes.length); // 32
 * ```
 */
export declare function getRandomBytes(length: number): Uint8Array;
/**
 * Compute SHA-1 hash of input data.
 *
 * Uses @noble/hashes for cross-platform SHA-1 implementation that works
 * in both browser and Node.js environments.
 *
 * @param data - String or Uint8Array to hash
 * @returns Uppercase hexadecimal string representation of the SHA-1 hash
 * @see Requirement 11.4
 *
 * @example
 * ```typescript
 * const hash = sha1Hash('password');
 * console.log(hash); // '5BAA61E4C9B93F3F0682250B6CF8331B7EE68FD8'
 * ```
 */
export declare function sha1Hash(data: string | Uint8Array): string;
/**
 * Compute SHA-1 hash of input data and return as Uint8Array.
 *
 * Uses @noble/hashes for cross-platform SHA-1 implementation that works
 * in both browser and Node.js environments.
 *
 * @param data - String or Uint8Array to hash
 * @returns Uint8Array containing the SHA-1 hash (20 bytes)
 * @see Requirement 11.4
 *
 * @example
 * ```typescript
 * const hashBytes = sha1HashBytes('password');
 * console.log(hashBytes.length); // 20
 * ```
 */
export declare function sha1HashBytes(data: string | Uint8Array): Uint8Array;
/**
 * Default implementation of IPlatformCrypto interface.
 *
 * Provides a class-based wrapper around the standalone functions
 * for use cases that prefer object-oriented patterns.
 */
export declare class PlatformCrypto implements IPlatformCrypto {
    /**
     * Generate cryptographically secure random bytes.
     * @param length - Number of bytes to generate
     * @returns Uint8Array of random bytes
     */
    randomBytes(length: number): Uint8Array;
    /**
     * Compute SHA-1 hash of input data.
     * @param data - String or Uint8Array to hash
     * @returns Uint8Array containing the hash
     */
    sha1(data: string | Uint8Array): Uint8Array;
}
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