231 lines
8.2 KiB
JavaScript
231 lines
8.2 KiB
JavaScript
"use strict";
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Object.defineProperty(exports, "__esModule", { value: true });
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exports.polyval = exports.ghash = void 0;
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exports._toGHASHKey = _toGHASHKey;
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/**
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* GHash from AES-GCM and its little-endian "mirror image" Polyval from AES-SIV.
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*
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* Implemented in terms of GHash with conversion function for keys
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* GCM GHASH from
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* [NIST SP800-38d](https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-38d.pdf),
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* SIV from
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* [RFC 8452](https://datatracker.ietf.org/doc/html/rfc8452).
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*
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* GHASH modulo: x^128 + x^7 + x^2 + x + 1
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* POLYVAL modulo: x^128 + x^127 + x^126 + x^121 + 1
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*
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* @module
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*/
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const _assert_js_1 = require("./_assert.js");
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const utils_js_1 = require("./utils.js");
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const BLOCK_SIZE = 16;
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// TODO: rewrite
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// temporary padding buffer
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const ZEROS16 = /* @__PURE__ */ new Uint8Array(16);
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const ZEROS32 = (0, utils_js_1.u32)(ZEROS16);
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const POLY = 0xe1; // v = 2*v % POLY
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// v = 2*v % POLY
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// NOTE: because x + x = 0 (add/sub is same), mul2(x) != x+x
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// We can multiply any number using montgomery ladder and this function (works as double, add is simple xor)
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const mul2 = (s0, s1, s2, s3) => {
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const hiBit = s3 & 1;
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return {
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s3: (s2 << 31) | (s3 >>> 1),
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s2: (s1 << 31) | (s2 >>> 1),
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s1: (s0 << 31) | (s1 >>> 1),
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s0: (s0 >>> 1) ^ ((POLY << 24) & -(hiBit & 1)), // reduce % poly
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};
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};
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const swapLE = (n) => (((n >>> 0) & 0xff) << 24) |
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(((n >>> 8) & 0xff) << 16) |
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(((n >>> 16) & 0xff) << 8) |
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((n >>> 24) & 0xff) |
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0;
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/**
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* `mulX_POLYVAL(ByteReverse(H))` from spec
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* @param k mutated in place
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*/
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function _toGHASHKey(k) {
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k.reverse();
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const hiBit = k[15] & 1;
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// k >>= 1
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let carry = 0;
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for (let i = 0; i < k.length; i++) {
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const t = k[i];
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k[i] = (t >>> 1) | carry;
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carry = (t & 1) << 7;
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}
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k[0] ^= -hiBit & 0xe1; // if (hiBit) n ^= 0xe1000000000000000000000000000000;
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return k;
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}
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const estimateWindow = (bytes) => {
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if (bytes > 64 * 1024)
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return 8;
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if (bytes > 1024)
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return 4;
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return 2;
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};
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class GHASH {
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// We select bits per window adaptively based on expectedLength
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constructor(key, expectedLength) {
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this.blockLen = BLOCK_SIZE;
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this.outputLen = BLOCK_SIZE;
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this.s0 = 0;
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this.s1 = 0;
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this.s2 = 0;
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this.s3 = 0;
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this.finished = false;
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key = (0, utils_js_1.toBytes)(key);
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(0, _assert_js_1.abytes)(key, 16);
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const kView = (0, utils_js_1.createView)(key);
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let k0 = kView.getUint32(0, false);
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let k1 = kView.getUint32(4, false);
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let k2 = kView.getUint32(8, false);
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let k3 = kView.getUint32(12, false);
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// generate table of doubled keys (half of montgomery ladder)
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const doubles = [];
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for (let i = 0; i < 128; i++) {
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doubles.push({ s0: swapLE(k0), s1: swapLE(k1), s2: swapLE(k2), s3: swapLE(k3) });
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({ s0: k0, s1: k1, s2: k2, s3: k3 } = mul2(k0, k1, k2, k3));
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}
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const W = estimateWindow(expectedLength || 1024);
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if (![1, 2, 4, 8].includes(W))
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throw new Error('ghash: invalid window size, expected 2, 4 or 8');
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this.W = W;
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const bits = 128; // always 128 bits;
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const windows = bits / W;
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const windowSize = (this.windowSize = 2 ** W);
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const items = [];
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// Create precompute table for window of W bits
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for (let w = 0; w < windows; w++) {
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// truth table: 00, 01, 10, 11
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for (let byte = 0; byte < windowSize; byte++) {
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// prettier-ignore
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let s0 = 0, s1 = 0, s2 = 0, s3 = 0;
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for (let j = 0; j < W; j++) {
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const bit = (byte >>> (W - j - 1)) & 1;
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if (!bit)
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continue;
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const { s0: d0, s1: d1, s2: d2, s3: d3 } = doubles[W * w + j];
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(s0 ^= d0), (s1 ^= d1), (s2 ^= d2), (s3 ^= d3);
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}
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items.push({ s0, s1, s2, s3 });
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}
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}
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this.t = items;
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}
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_updateBlock(s0, s1, s2, s3) {
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(s0 ^= this.s0), (s1 ^= this.s1), (s2 ^= this.s2), (s3 ^= this.s3);
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const { W, t, windowSize } = this;
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// prettier-ignore
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let o0 = 0, o1 = 0, o2 = 0, o3 = 0;
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const mask = (1 << W) - 1; // 2**W will kill performance.
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let w = 0;
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for (const num of [s0, s1, s2, s3]) {
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for (let bytePos = 0; bytePos < 4; bytePos++) {
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const byte = (num >>> (8 * bytePos)) & 0xff;
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for (let bitPos = 8 / W - 1; bitPos >= 0; bitPos--) {
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const bit = (byte >>> (W * bitPos)) & mask;
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const { s0: e0, s1: e1, s2: e2, s3: e3 } = t[w * windowSize + bit];
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(o0 ^= e0), (o1 ^= e1), (o2 ^= e2), (o3 ^= e3);
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w += 1;
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}
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}
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}
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this.s0 = o0;
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this.s1 = o1;
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this.s2 = o2;
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this.s3 = o3;
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}
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update(data) {
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data = (0, utils_js_1.toBytes)(data);
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(0, _assert_js_1.aexists)(this);
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const b32 = (0, utils_js_1.u32)(data);
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const blocks = Math.floor(data.length / BLOCK_SIZE);
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const left = data.length % BLOCK_SIZE;
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for (let i = 0; i < blocks; i++) {
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this._updateBlock(b32[i * 4 + 0], b32[i * 4 + 1], b32[i * 4 + 2], b32[i * 4 + 3]);
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}
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if (left) {
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ZEROS16.set(data.subarray(blocks * BLOCK_SIZE));
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this._updateBlock(ZEROS32[0], ZEROS32[1], ZEROS32[2], ZEROS32[3]);
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(0, utils_js_1.clean)(ZEROS32); // clean tmp buffer
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}
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return this;
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}
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destroy() {
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const { t } = this;
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// clean precompute table
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for (const elm of t) {
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(elm.s0 = 0), (elm.s1 = 0), (elm.s2 = 0), (elm.s3 = 0);
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}
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}
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digestInto(out) {
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(0, _assert_js_1.aexists)(this);
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(0, _assert_js_1.aoutput)(out, this);
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this.finished = true;
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const { s0, s1, s2, s3 } = this;
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const o32 = (0, utils_js_1.u32)(out);
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o32[0] = s0;
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o32[1] = s1;
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o32[2] = s2;
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o32[3] = s3;
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return out;
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}
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digest() {
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const res = new Uint8Array(BLOCK_SIZE);
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this.digestInto(res);
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this.destroy();
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return res;
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}
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}
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class Polyval extends GHASH {
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constructor(key, expectedLength) {
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key = (0, utils_js_1.toBytes)(key);
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const ghKey = _toGHASHKey((0, utils_js_1.copyBytes)(key));
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super(ghKey, expectedLength);
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(0, utils_js_1.clean)(ghKey);
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}
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update(data) {
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data = (0, utils_js_1.toBytes)(data);
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(0, _assert_js_1.aexists)(this);
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const b32 = (0, utils_js_1.u32)(data);
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const left = data.length % BLOCK_SIZE;
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const blocks = Math.floor(data.length / BLOCK_SIZE);
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for (let i = 0; i < blocks; i++) {
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this._updateBlock(swapLE(b32[i * 4 + 3]), swapLE(b32[i * 4 + 2]), swapLE(b32[i * 4 + 1]), swapLE(b32[i * 4 + 0]));
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}
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if (left) {
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ZEROS16.set(data.subarray(blocks * BLOCK_SIZE));
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this._updateBlock(swapLE(ZEROS32[3]), swapLE(ZEROS32[2]), swapLE(ZEROS32[1]), swapLE(ZEROS32[0]));
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(0, utils_js_1.clean)(ZEROS32);
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}
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return this;
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}
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digestInto(out) {
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(0, _assert_js_1.aexists)(this);
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(0, _assert_js_1.aoutput)(out, this);
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this.finished = true;
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// tmp ugly hack
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const { s0, s1, s2, s3 } = this;
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const o32 = (0, utils_js_1.u32)(out);
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o32[0] = s0;
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o32[1] = s1;
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o32[2] = s2;
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o32[3] = s3;
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return out.reverse();
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}
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}
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function wrapConstructorWithKey(hashCons) {
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const hashC = (msg, key) => hashCons(key, msg.length).update((0, utils_js_1.toBytes)(msg)).digest();
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const tmp = hashCons(new Uint8Array(16), 0);
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hashC.outputLen = tmp.outputLen;
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hashC.blockLen = tmp.blockLen;
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hashC.create = (key, expectedLength) => hashCons(key, expectedLength);
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return hashC;
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}
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/** GHash MAC for AES-GCM. */
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exports.ghash = wrapConstructorWithKey((key, expectedLength) => new GHASH(key, expectedLength));
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/** Polyval MAC for AES-SIV. */
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exports.polyval = wrapConstructorWithKey((key, expectedLength) => new Polyval(key, expectedLength));
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//# sourceMappingURL=_polyval.js.map
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