Scott Nonnenberg
parent
817cf5ed03
commit
a7d78c0e9b
38 changed files with 2996 additions and 789 deletions
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@ -1,39 +1,82 @@
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/* eslint-env browser */
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/* global dcodeIO */
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/* eslint-disable camelcase */
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/* eslint-disable camelcase, no-bitwise */
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module.exports = {
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encryptSymmetric,
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decryptSymmetric,
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arrayBufferToBase64,
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base64ToArrayBuffer,
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bytesFromString,
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concatenateBytes,
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constantTimeEqual,
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decryptAesCtr,
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decryptSymmetric,
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deriveAccessKey,
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encryptAesCtr,
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encryptSymmetric,
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fromEncodedBinaryToArrayBuffer,
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getAccessKeyVerifier,
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getRandomBytes,
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getViewOfArrayBuffer,
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getZeroes,
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highBitsToInt,
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hmacSha256,
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intsToByteHighAndLow,
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splitBytes,
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stringFromBytes,
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trimBytes,
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verifyAccessKey,
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};
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// High-level Operations
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async function deriveAccessKey(profileKey) {
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const iv = getZeroes(12);
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const plaintext = getZeroes(16);
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const accessKey = await _encrypt_aes_gcm(profileKey, iv, plaintext);
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return _getFirstBytes(accessKey, 16);
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}
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async function getAccessKeyVerifier(accessKey) {
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const plaintext = getZeroes(32);
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const hmac = await hmacSha256(accessKey, plaintext);
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return hmac;
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}
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async function verifyAccessKey(accessKey, theirVerifier) {
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const ourVerifier = await getAccessKeyVerifier(accessKey);
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if (constantTimeEqual(ourVerifier, theirVerifier)) {
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return true;
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}
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return false;
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}
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const IV_LENGTH = 16;
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const MAC_LENGTH = 16;
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const NONCE_LENGTH = 16;
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async function encryptSymmetric(key, plaintext) {
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const iv = _getZeros(IV_LENGTH);
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const nonce = _getRandomBytes(NONCE_LENGTH);
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const iv = getZeroes(IV_LENGTH);
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const nonce = getRandomBytes(NONCE_LENGTH);
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const cipherKey = await _hmac_SHA256(key, nonce);
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const macKey = await _hmac_SHA256(key, cipherKey);
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const cipherKey = await hmacSha256(key, nonce);
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const macKey = await hmacSha256(key, cipherKey);
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const cipherText = await _encrypt_aes256_CBC_PKCSPadding(
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cipherKey,
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iv,
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plaintext
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);
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const mac = _getFirstBytes(
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await _hmac_SHA256(macKey, cipherText),
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MAC_LENGTH
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);
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const mac = _getFirstBytes(await hmacSha256(macKey, cipherText), MAC_LENGTH);
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return _concatData([nonce, cipherText, mac]);
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return concatenateBytes(nonce, cipherText, mac);
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}
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async function decryptSymmetric(key, data) {
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const iv = _getZeros(IV_LENGTH);
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const iv = getZeroes(IV_LENGTH);
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const nonce = _getFirstBytes(data, NONCE_LENGTH);
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const cipherText = _getBytes(
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@ -43,11 +86,11 @@ async function decryptSymmetric(key, data) {
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);
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const theirMac = _getBytes(data, data.byteLength - MAC_LENGTH, MAC_LENGTH);
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const cipherKey = await _hmac_SHA256(key, nonce);
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const macKey = await _hmac_SHA256(key, cipherKey);
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const cipherKey = await hmacSha256(key, nonce);
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const macKey = await hmacSha256(key, cipherKey);
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const ourMac = _getFirstBytes(
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await _hmac_SHA256(macKey, cipherText),
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await hmacSha256(macKey, cipherText),
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MAC_LENGTH
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);
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if (!constantTimeEqual(theirMac, ourMac)) {
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@ -73,56 +116,135 @@ function constantTimeEqual(left, right) {
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return result === 0;
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}
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async function _hmac_SHA256(key, data) {
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// Encryption
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async function hmacSha256(key, plaintext) {
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const algorithm = {
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name: 'HMAC',
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hash: 'SHA-256',
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};
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const extractable = false;
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const cryptoKey = await window.crypto.subtle.importKey(
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'raw',
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key,
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{ name: 'HMAC', hash: { name: 'SHA-256' } },
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algorithm,
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extractable,
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['sign']
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);
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return window.crypto.subtle.sign(
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{ name: 'HMAC', hash: 'SHA-256' },
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cryptoKey,
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data
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);
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return window.crypto.subtle.sign(algorithm, cryptoKey, plaintext);
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}
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async function _encrypt_aes256_CBC_PKCSPadding(key, iv, data) {
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async function _encrypt_aes256_CBC_PKCSPadding(key, iv, plaintext) {
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const algorithm = {
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name: 'AES-CBC',
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iv,
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};
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const extractable = false;
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const cryptoKey = await window.crypto.subtle.importKey(
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'raw',
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key,
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{ name: 'AES-CBC' },
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algorithm,
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extractable,
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['encrypt']
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);
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return window.crypto.subtle.encrypt({ name: 'AES-CBC', iv }, cryptoKey, data);
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return window.crypto.subtle.encrypt(algorithm, cryptoKey, plaintext);
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}
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async function _decrypt_aes256_CBC_PKCSPadding(key, iv, data) {
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async function _decrypt_aes256_CBC_PKCSPadding(key, iv, plaintext) {
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const algorithm = {
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name: 'AES-CBC',
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iv,
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};
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const extractable = false;
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const cryptoKey = await window.crypto.subtle.importKey(
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'raw',
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key,
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{ name: 'AES-CBC' },
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algorithm,
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extractable,
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['decrypt']
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);
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return window.crypto.subtle.decrypt({ name: 'AES-CBC', iv }, cryptoKey, data);
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return window.crypto.subtle.decrypt(algorithm, cryptoKey, plaintext);
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}
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function _getRandomBytes(n) {
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async function encryptAesCtr(key, plaintext, counter) {
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const extractable = false;
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const algorithm = {
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name: 'AES-CTR',
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counter: new Uint8Array(counter),
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length: 128,
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};
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const cryptoKey = await crypto.subtle.importKey(
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'raw',
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key,
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algorithm,
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extractable,
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['encrypt']
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);
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const ciphertext = await crypto.subtle.encrypt(
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algorithm,
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cryptoKey,
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plaintext
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);
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return ciphertext;
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}
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async function decryptAesCtr(key, ciphertext, counter) {
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const extractable = false;
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const algorithm = {
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name: 'AES-CTR',
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counter: new Uint8Array(counter),
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length: 128,
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};
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const cryptoKey = await crypto.subtle.importKey(
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'raw',
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key,
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algorithm,
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extractable,
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['decrypt']
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);
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const plaintext = await crypto.subtle.decrypt(
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algorithm,
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cryptoKey,
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ciphertext
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);
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return plaintext;
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}
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async function _encrypt_aes_gcm(key, iv, plaintext) {
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const algorithm = {
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name: 'AES-GCM',
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iv,
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};
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const extractable = false;
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const cryptoKey = await crypto.subtle.importKey(
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'raw',
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key,
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algorithm,
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extractable,
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['encrypt']
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);
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return crypto.subtle.encrypt(algorithm, cryptoKey, plaintext);
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}
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// Utility
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function getRandomBytes(n) {
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const bytes = new Uint8Array(n);
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window.crypto.getRandomValues(bytes);
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return bytes;
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}
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function _getZeros(n) {
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function getZeroes(n) {
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const result = new Uint8Array(n);
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const value = 0;
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return result;
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}
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function _getFirstBytes(data, n) {
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const source = new Uint8Array(data);
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return source.subarray(0, n);
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function highBitsToInt(byte) {
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return (byte & 0xff) >> 4;
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}
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function _getBytes(data, start, n) {
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const source = new Uint8Array(data);
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return source.subarray(start, start + n);
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function intsToByteHighAndLow(highValue, lowValue) {
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return ((highValue << 4) | lowValue) & 0xff;
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}
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function _concatData(elements) {
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function trimBytes(buffer, length) {
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return _getFirstBytes(buffer, length);
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}
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function arrayBufferToBase64(arrayBuffer) {
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return dcodeIO.ByteBuffer.wrap(arrayBuffer).toString('base64');
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}
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function base64ToArrayBuffer(base64string) {
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return dcodeIO.ByteBuffer.wrap(base64string, 'base64').toArrayBuffer();
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}
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function fromEncodedBinaryToArrayBuffer(key) {
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return dcodeIO.ByteBuffer.wrap(key, 'binary').toArrayBuffer();
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}
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function bytesFromString(string) {
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return dcodeIO.ByteBuffer.wrap(string, 'utf8').toArrayBuffer();
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}
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function stringFromBytes(buffer) {
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return dcodeIO.ByteBuffer.wrap(buffer).toString('utf8');
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}
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function getViewOfArrayBuffer(buffer, start, finish) {
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const source = new Uint8Array(buffer);
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const result = source.slice(start, finish);
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return result.buffer;
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}
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function concatenateBytes(...elements) {
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const length = elements.reduce(
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(total, element) => total + element.byteLength,
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0
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@ -161,5 +309,45 @@ function _concatData(elements) {
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throw new Error('problem concatenating!');
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}
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return result;
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return result.buffer;
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}
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function splitBytes(buffer, ...lengths) {
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const total = lengths.reduce((acc, length) => acc + length, 0);
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if (total !== buffer.byteLength) {
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throw new Error(
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`Requested lengths total ${total} does not match source total ${
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buffer.byteLength
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}`
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);
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}
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const source = new Uint8Array(buffer);
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const results = [];
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let position = 0;
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for (let i = 0, max = lengths.length; i < max; i += 1) {
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const length = lengths[i];
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const result = new Uint8Array(length);
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const section = source.slice(position, position + length);
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result.set(section);
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position += result.byteLength;
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results.push(result);
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}
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return results;
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}
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// Internal-only
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function _getFirstBytes(data, n) {
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const source = new Uint8Array(data);
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return source.subarray(0, n);
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}
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function _getBytes(data, start, n) {
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const source = new Uint8Array(data);
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return source.subarray(start, start + n);
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}
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