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1/*2 * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.3 * SPDX-License-Identifier: Apache-2.0.4 */5 6/**7 * A module containing support for a variety of cryptographic operations.8 *9 * @packageDocumentation10 * @module crypto11 * @mergeTarget12 */13 14import * as Crypto from "crypto-js";15import { Hashable } from "../common/crypto";16 17export { Hashable } from "../common/crypto";18 19/**20 * CryptoJS does not provide easy access to underlying bytes.21 * As a workaround just dump it to a string and then reinterpret chars as individual bytes.22 * Note: we are using Latin1 here because its a static sized 8 bit encoding so each char maps directly to a byte value.23 * TODO: long term we would probably want to move to WebCrypto for SHA's and some other 3p for crc's and md5.24 * @param hash 25 * @returns 26 */27function wordArrayToUint8Array(hash: Crypto.WordArray) {28    return Uint8Array.from(hash.toString(Crypto.enc.Latin1).split('').map(c => c.charCodeAt(0)));;29}30 31class BaseHash {32    private hasher : any;33 34    constructor(hasher: any) {35        this.hasher = hasher;36    }37 38    /**39     * Hashes additional data40     * @param data Additional data to hash41     */42    update(data: Hashable) {43        this.hasher.update(data.toString());44    }45 46    /**47     * Completes the hash computation and returns the final hash digest.48     *49     * @param truncate_to The maximum number of bytes to receive. Leave as undefined or 0 to receive the entire digest.50     *51     * @returns the final hash digest52     */53    finalize(truncate_to?: number): DataView {54        const hashBuffer = wordArrayToUint8Array(this.hasher.finalize()) ;55        const truncated = hashBuffer.slice(0, truncate_to ? truncate_to : hashBuffer.length);56        return new DataView(truncated.buffer);;57    }58}59 60/**61 * Object that allows for continuous MD5 hashing of data.62 *63 * @category Crypto64 */65export class Md5Hash extends BaseHash {66    constructor() {67        super(Crypto.algo.MD5.create());68    }69}70 71 72/**73 * Computes an MD5 hash. Use this if you don't need to stream the data you're hashing and can load the entire input74 * into memory.75 *76 * @param data The data to hash77 * @param truncate_to The maximum number of bytes to receive. Leave as undefined or 0 to receive the entire digest.78 *79 * @returns the data's hash digest80 *81 * @category Crypto82 */83export function hash_md5(data: Hashable, truncate_to?: number): DataView {84    const md5 = new Md5Hash();85    md5.update(data);86    return md5.finalize(truncate_to);87}88 89/**90 * Object that allows for continuous SHA256 hashing of data.91 *92 * @category Crypto93 */94export class Sha256Hash extends BaseHash {95    constructor() {96        super(Crypto.algo.SHA256.create());97    }98}99 100/**101 * Computes an SHA256 hash. Use this if you don't need to stream the data you're hashing and can load the entire input102 * into memory.103 *104 * @param data The data to hash105 * @param truncate_to The maximum number of bytes to receive. Leave as undefined or 0 to receive the entire digest.106 *107 * @returns the data's hash digest108 *109 * @category Crypto110 */111export function hash_sha256(data: Hashable, truncate_to?: number): DataView {112    const sha256 = new Sha256Hash();113    sha256.update(data);114    return sha256.finalize(truncate_to);115}116 117/**118 * Object that allows for continuous SHA1 hashing of data.119 *120 * @category Crypto121 */122 export class Sha1Hash extends BaseHash {123    constructor() {124        super(Crypto.algo.SHA1.create());125    }126}127 128/**129 * Computes an SHA1 hash. Use this if you don't need to stream the data you're hashing and can load the entire input130 * into memory.131 *132 * @param data The data to hash133 * @param truncate_to The maximum number of bytes to receive. Leave as undefined or 0 to receive the entire digest.134 *135 * @returns the data's hash digest136 *137 * @category Crypto138 */139export function hash_sha1(data: Hashable, truncate_to?: number): DataView {140    const sha1 = new Sha1Hash();141    sha1.update(data);142    return sha1.finalize(truncate_to);143}144 145/**146 * Object that allows for continuous hashing of data with an hmac secret.147 *148 * @category Crypto149 */150export class Sha256Hmac extends BaseHash {151    /**152     * Constructor for the Sha256Hmac class type153     * @param secret secret key to seed the hmac process with154     */155    constructor(secret: Hashable) {156        // @ts-ignore types file doesn't have this signature of create()157        super(Crypto.algo.HMAC.create(Crypto.algo.SHA256, secret));158    }159}160 161/**162 * Computes an SHA256 HMAC. Use this if you don't need to stream the data you're hashing and can load the entire input163 * into memory.164 *165 * @param secret The key to use for the HMAC process166 * @param data The data to hash167 * @param truncate_to The maximum number of bytes to receive. Leave as undefined or 0 to receive the entire digest.168 *169 * @returns the data's hmac digest170 *171 * @category Crypto172 */173export function hmac_sha256(secret: Hashable, data: Hashable, truncate_to?: number): DataView {174    const hmac = new Sha256Hmac(secret);175    hmac.update(data);176    return hmac.finalize(truncate_to);177}178