Move web_api.js and js/modules/crypto.js to TypeScript
This commit is contained in:
parent
71436d18e2
commit
9ab54b9b83
29 changed files with 770 additions and 427 deletions
540
ts/Crypto.ts
Normal file
540
ts/Crypto.ts
Normal file
|
@ -0,0 +1,540 @@
|
|||
// Yep, we're doing some bitwise stuff in an encryption-related file
|
||||
// tslint:disable no-bitwise
|
||||
|
||||
// We want some extra variables to make the decrption algorithm easier to understand
|
||||
// tslint:disable no-unnecessary-local-variable
|
||||
|
||||
// Seems that tslint doesn't understand that crypto.subtle.importKey does return a Promise
|
||||
// tslint:disable await-promise
|
||||
|
||||
export function typedArrayToArrayBuffer(typedArray: Uint8Array): ArrayBuffer {
|
||||
const { buffer, byteOffset, byteLength } = typedArray;
|
||||
|
||||
// tslint:disable-next-line no-unnecessary-type-assertion
|
||||
return buffer.slice(byteOffset, byteLength + byteOffset) as ArrayBuffer;
|
||||
}
|
||||
|
||||
export function arrayBufferToBase64(arrayBuffer: ArrayBuffer) {
|
||||
return window.dcodeIO.ByteBuffer.wrap(arrayBuffer).toString('base64');
|
||||
}
|
||||
export function base64ToArrayBuffer(base64string: string) {
|
||||
return window.dcodeIO.ByteBuffer.wrap(base64string, 'base64').toArrayBuffer();
|
||||
}
|
||||
|
||||
export function fromEncodedBinaryToArrayBuffer(key: string) {
|
||||
return window.dcodeIO.ByteBuffer.wrap(key, 'binary').toArrayBuffer();
|
||||
}
|
||||
|
||||
export function bytesFromString(string: string) {
|
||||
return window.dcodeIO.ByteBuffer.wrap(string, 'utf8').toArrayBuffer();
|
||||
}
|
||||
export function stringFromBytes(buffer: ArrayBuffer) {
|
||||
return window.dcodeIO.ByteBuffer.wrap(buffer).toString('utf8');
|
||||
}
|
||||
export function hexFromBytes(buffer: ArrayBuffer) {
|
||||
return window.dcodeIO.ByteBuffer.wrap(buffer).toString('hex');
|
||||
}
|
||||
export function bytesFromHexString(string: string) {
|
||||
return window.dcodeIO.ByteBuffer.wrap(string, 'hex').toArrayBuffer();
|
||||
}
|
||||
|
||||
export async function deriveStickerPackKey(packKey: ArrayBuffer) {
|
||||
const salt = getZeroes(32);
|
||||
const info = bytesFromString('Sticker Pack');
|
||||
|
||||
const [part1, part2] = await window.libsignal.HKDF.deriveSecrets(
|
||||
packKey,
|
||||
salt,
|
||||
info
|
||||
);
|
||||
|
||||
return concatenateBytes(part1, part2);
|
||||
}
|
||||
|
||||
// High-level Operations
|
||||
|
||||
export async function encryptDeviceName(
|
||||
deviceName: string,
|
||||
identityPublic: ArrayBuffer
|
||||
) {
|
||||
const plaintext = bytesFromString(deviceName);
|
||||
const ephemeralKeyPair = await window.libsignal.KeyHelper.generateIdentityKeyPair();
|
||||
const masterSecret = await window.libsignal.Curve.async.calculateAgreement(
|
||||
identityPublic,
|
||||
ephemeralKeyPair.privKey
|
||||
);
|
||||
|
||||
const key1 = await hmacSha256(masterSecret, bytesFromString('auth'));
|
||||
const syntheticIv = getFirstBytes(await hmacSha256(key1, plaintext), 16);
|
||||
|
||||
const key2 = await hmacSha256(masterSecret, bytesFromString('cipher'));
|
||||
const cipherKey = await hmacSha256(key2, syntheticIv);
|
||||
|
||||
const counter = getZeroes(16);
|
||||
const ciphertext = await encryptAesCtr(cipherKey, plaintext, counter);
|
||||
|
||||
return {
|
||||
ephemeralPublic: ephemeralKeyPair.pubKey,
|
||||
syntheticIv,
|
||||
ciphertext,
|
||||
};
|
||||
}
|
||||
|
||||
export async function decryptDeviceName(
|
||||
{
|
||||
ephemeralPublic,
|
||||
syntheticIv,
|
||||
ciphertext,
|
||||
}: {
|
||||
ephemeralPublic: ArrayBuffer;
|
||||
syntheticIv: ArrayBuffer;
|
||||
ciphertext: ArrayBuffer;
|
||||
},
|
||||
identityPrivate: ArrayBuffer
|
||||
) {
|
||||
const masterSecret = await window.libsignal.Curve.async.calculateAgreement(
|
||||
ephemeralPublic,
|
||||
identityPrivate
|
||||
);
|
||||
|
||||
const key2 = await hmacSha256(masterSecret, bytesFromString('cipher'));
|
||||
const cipherKey = await hmacSha256(key2, syntheticIv);
|
||||
|
||||
const counter = getZeroes(16);
|
||||
const plaintext = await decryptAesCtr(cipherKey, ciphertext, counter);
|
||||
|
||||
const key1 = await hmacSha256(masterSecret, bytesFromString('auth'));
|
||||
const ourSyntheticIv = getFirstBytes(await hmacSha256(key1, plaintext), 16);
|
||||
|
||||
if (!constantTimeEqual(ourSyntheticIv, syntheticIv)) {
|
||||
throw new Error('decryptDeviceName: synthetic IV did not match');
|
||||
}
|
||||
|
||||
return stringFromBytes(plaintext);
|
||||
}
|
||||
|
||||
// Path structure: 'fa/facdf99c22945b1c9393345599a276f4b36ad7ccdc8c2467f5441b742c2d11fa'
|
||||
export function getAttachmentLabel(path: string) {
|
||||
const filename = path.slice(3);
|
||||
|
||||
return base64ToArrayBuffer(filename);
|
||||
}
|
||||
|
||||
const PUB_KEY_LENGTH = 32;
|
||||
export async function encryptAttachment(
|
||||
staticPublicKey: ArrayBuffer,
|
||||
path: string,
|
||||
plaintext: ArrayBuffer
|
||||
) {
|
||||
const uniqueId = getAttachmentLabel(path);
|
||||
|
||||
return encryptFile(staticPublicKey, uniqueId, plaintext);
|
||||
}
|
||||
|
||||
export async function decryptAttachment(
|
||||
staticPrivateKey: ArrayBuffer,
|
||||
path: string,
|
||||
data: ArrayBuffer
|
||||
) {
|
||||
const uniqueId = getAttachmentLabel(path);
|
||||
|
||||
return decryptFile(staticPrivateKey, uniqueId, data);
|
||||
}
|
||||
|
||||
export async function encryptFile(
|
||||
staticPublicKey: ArrayBuffer,
|
||||
uniqueId: ArrayBuffer,
|
||||
plaintext: ArrayBuffer
|
||||
) {
|
||||
const ephemeralKeyPair = await window.libsignal.KeyHelper.generateIdentityKeyPair();
|
||||
const agreement = await window.libsignal.Curve.async.calculateAgreement(
|
||||
staticPublicKey,
|
||||
ephemeralKeyPair.privKey
|
||||
);
|
||||
const key = await hmacSha256(agreement, uniqueId);
|
||||
|
||||
const prefix = ephemeralKeyPair.pubKey.slice(1);
|
||||
|
||||
return concatenateBytes(prefix, await encryptSymmetric(key, plaintext));
|
||||
}
|
||||
|
||||
export async function decryptFile(
|
||||
staticPrivateKey: ArrayBuffer,
|
||||
uniqueId: ArrayBuffer,
|
||||
data: ArrayBuffer
|
||||
) {
|
||||
const ephemeralPublicKey = getFirstBytes(data, PUB_KEY_LENGTH);
|
||||
const ciphertext = _getBytes(data, PUB_KEY_LENGTH, data.byteLength);
|
||||
const agreement = await window.libsignal.Curve.async.calculateAgreement(
|
||||
ephemeralPublicKey,
|
||||
staticPrivateKey
|
||||
);
|
||||
|
||||
const key = await hmacSha256(agreement, uniqueId);
|
||||
|
||||
return decryptSymmetric(key, ciphertext);
|
||||
}
|
||||
|
||||
export async function deriveAccessKey(profileKey: ArrayBuffer) {
|
||||
const iv = getZeroes(12);
|
||||
const plaintext = getZeroes(16);
|
||||
const accessKey = await _encrypt_aes_gcm(profileKey, iv, plaintext);
|
||||
|
||||
return getFirstBytes(accessKey, 16);
|
||||
}
|
||||
|
||||
export async function getAccessKeyVerifier(accessKey: ArrayBuffer) {
|
||||
const plaintext = getZeroes(32);
|
||||
|
||||
return hmacSha256(accessKey, plaintext);
|
||||
}
|
||||
|
||||
export async function verifyAccessKey(
|
||||
accessKey: ArrayBuffer,
|
||||
theirVerifier: ArrayBuffer
|
||||
) {
|
||||
const ourVerifier = await getAccessKeyVerifier(accessKey);
|
||||
|
||||
if (constantTimeEqual(ourVerifier, theirVerifier)) {
|
||||
return true;
|
||||
}
|
||||
|
||||
return false;
|
||||
}
|
||||
|
||||
const IV_LENGTH = 16;
|
||||
const MAC_LENGTH = 16;
|
||||
const NONCE_LENGTH = 16;
|
||||
|
||||
export async function encryptSymmetric(
|
||||
key: ArrayBuffer,
|
||||
plaintext: ArrayBuffer
|
||||
) {
|
||||
const iv = getZeroes(IV_LENGTH);
|
||||
const nonce = getRandomBytes(NONCE_LENGTH);
|
||||
|
||||
const cipherKey = await hmacSha256(key, nonce);
|
||||
const macKey = await hmacSha256(key, cipherKey);
|
||||
|
||||
const cipherText = await _encrypt_aes256_CBC_PKCSPadding(
|
||||
cipherKey,
|
||||
iv,
|
||||
plaintext
|
||||
);
|
||||
const mac = getFirstBytes(await hmacSha256(macKey, cipherText), MAC_LENGTH);
|
||||
|
||||
return concatenateBytes(nonce, cipherText, mac);
|
||||
}
|
||||
|
||||
export async function decryptSymmetric(key: ArrayBuffer, data: ArrayBuffer) {
|
||||
const iv = getZeroes(IV_LENGTH);
|
||||
|
||||
const nonce = getFirstBytes(data, NONCE_LENGTH);
|
||||
const cipherText = _getBytes(
|
||||
data,
|
||||
NONCE_LENGTH,
|
||||
data.byteLength - NONCE_LENGTH - MAC_LENGTH
|
||||
);
|
||||
const theirMac = _getBytes(data, data.byteLength - MAC_LENGTH, MAC_LENGTH);
|
||||
|
||||
const cipherKey = await hmacSha256(key, nonce);
|
||||
const macKey = await hmacSha256(key, cipherKey);
|
||||
|
||||
const ourMac = getFirstBytes(
|
||||
await hmacSha256(macKey, cipherText),
|
||||
MAC_LENGTH
|
||||
);
|
||||
if (!constantTimeEqual(theirMac, ourMac)) {
|
||||
throw new Error(
|
||||
'decryptSymmetric: Failed to decrypt; MAC verification failed'
|
||||
);
|
||||
}
|
||||
|
||||
return _decrypt_aes256_CBC_PKCSPadding(cipherKey, iv, cipherText);
|
||||
}
|
||||
|
||||
export function constantTimeEqual(left: ArrayBuffer, right: ArrayBuffer) {
|
||||
if (left.byteLength !== right.byteLength) {
|
||||
return false;
|
||||
}
|
||||
let result = 0;
|
||||
const ta1 = new Uint8Array(left);
|
||||
const ta2 = new Uint8Array(right);
|
||||
const max = left.byteLength;
|
||||
for (let i = 0; i < max; i += 1) {
|
||||
// eslint-disable-next-line no-bitwise
|
||||
result |= ta1[i] ^ ta2[i];
|
||||
}
|
||||
|
||||
return result === 0;
|
||||
}
|
||||
|
||||
// Encryption
|
||||
|
||||
export async function hmacSha256(key: ArrayBuffer, plaintext: ArrayBuffer) {
|
||||
const algorithm = {
|
||||
name: 'HMAC',
|
||||
hash: 'SHA-256',
|
||||
};
|
||||
const extractable = false;
|
||||
|
||||
const cryptoKey = await window.crypto.subtle.importKey(
|
||||
'raw',
|
||||
key,
|
||||
algorithm as any,
|
||||
extractable,
|
||||
['sign']
|
||||
);
|
||||
|
||||
return window.crypto.subtle.sign(algorithm, cryptoKey, plaintext);
|
||||
}
|
||||
|
||||
export async function _encrypt_aes256_CBC_PKCSPadding(
|
||||
key: ArrayBuffer,
|
||||
iv: ArrayBuffer,
|
||||
plaintext: ArrayBuffer
|
||||
) {
|
||||
const algorithm = {
|
||||
name: 'AES-CBC',
|
||||
iv,
|
||||
};
|
||||
const extractable = false;
|
||||
|
||||
const cryptoKey = await window.crypto.subtle.importKey(
|
||||
'raw',
|
||||
key,
|
||||
algorithm as any,
|
||||
extractable,
|
||||
['encrypt']
|
||||
);
|
||||
|
||||
return window.crypto.subtle.encrypt(algorithm, cryptoKey, plaintext);
|
||||
}
|
||||
|
||||
export async function _decrypt_aes256_CBC_PKCSPadding(
|
||||
key: ArrayBuffer,
|
||||
iv: ArrayBuffer,
|
||||
plaintext: ArrayBuffer
|
||||
) {
|
||||
const algorithm = {
|
||||
name: 'AES-CBC',
|
||||
iv,
|
||||
};
|
||||
const extractable = false;
|
||||
|
||||
const cryptoKey = await window.crypto.subtle.importKey(
|
||||
'raw',
|
||||
key,
|
||||
algorithm as any,
|
||||
extractable,
|
||||
['decrypt']
|
||||
);
|
||||
|
||||
return window.crypto.subtle.decrypt(algorithm, cryptoKey, plaintext);
|
||||
}
|
||||
|
||||
export async function encryptAesCtr(
|
||||
key: ArrayBuffer,
|
||||
plaintext: ArrayBuffer,
|
||||
counter: ArrayBuffer
|
||||
) {
|
||||
const extractable = false;
|
||||
const algorithm = {
|
||||
name: 'AES-CTR',
|
||||
counter: new Uint8Array(counter),
|
||||
length: 128,
|
||||
};
|
||||
|
||||
const cryptoKey = await crypto.subtle.importKey(
|
||||
'raw',
|
||||
key,
|
||||
algorithm as any,
|
||||
extractable,
|
||||
['encrypt']
|
||||
);
|
||||
|
||||
const ciphertext = await crypto.subtle.encrypt(
|
||||
algorithm,
|
||||
cryptoKey,
|
||||
plaintext
|
||||
);
|
||||
|
||||
return ciphertext;
|
||||
}
|
||||
|
||||
export async function decryptAesCtr(
|
||||
key: ArrayBuffer,
|
||||
ciphertext: ArrayBuffer,
|
||||
counter: ArrayBuffer
|
||||
) {
|
||||
const extractable = false;
|
||||
const algorithm = {
|
||||
name: 'AES-CTR',
|
||||
counter: new Uint8Array(counter),
|
||||
length: 128,
|
||||
};
|
||||
|
||||
const cryptoKey = await crypto.subtle.importKey(
|
||||
'raw',
|
||||
key,
|
||||
algorithm as any,
|
||||
extractable,
|
||||
['decrypt']
|
||||
);
|
||||
const plaintext = await crypto.subtle.decrypt(
|
||||
algorithm,
|
||||
cryptoKey,
|
||||
ciphertext
|
||||
);
|
||||
|
||||
return plaintext;
|
||||
}
|
||||
|
||||
export async function _encrypt_aes_gcm(
|
||||
key: ArrayBuffer,
|
||||
iv: ArrayBuffer,
|
||||
plaintext: ArrayBuffer
|
||||
) {
|
||||
const algorithm = {
|
||||
name: 'AES-GCM',
|
||||
iv,
|
||||
};
|
||||
const extractable = false;
|
||||
|
||||
const cryptoKey = await crypto.subtle.importKey(
|
||||
'raw',
|
||||
key,
|
||||
algorithm as any,
|
||||
extractable,
|
||||
['encrypt']
|
||||
);
|
||||
|
||||
return crypto.subtle.encrypt(algorithm, cryptoKey, plaintext);
|
||||
}
|
||||
|
||||
// Utility
|
||||
|
||||
export function getRandomBytes(n: number) {
|
||||
const bytes = new Uint8Array(n);
|
||||
window.crypto.getRandomValues(bytes);
|
||||
|
||||
return typedArrayToArrayBuffer(bytes);
|
||||
}
|
||||
|
||||
export function getRandomValue(low: number, high: number): number {
|
||||
const diff = high - low;
|
||||
const bytes = new Uint32Array(1);
|
||||
window.crypto.getRandomValues(bytes);
|
||||
|
||||
// Because high and low are inclusive
|
||||
const mod = diff + 1;
|
||||
|
||||
return (bytes[0] % mod) + low;
|
||||
}
|
||||
|
||||
export function getZeroes(n: number) {
|
||||
const result = new Uint8Array(n);
|
||||
|
||||
const value = 0;
|
||||
const startIndex = 0;
|
||||
const endExclusive = n;
|
||||
result.fill(value, startIndex, endExclusive);
|
||||
|
||||
return typedArrayToArrayBuffer(result);
|
||||
}
|
||||
|
||||
export function highBitsToInt(byte: number): number {
|
||||
return (byte & 0xff) >> 4;
|
||||
}
|
||||
|
||||
export function intsToByteHighAndLow(
|
||||
highValue: number,
|
||||
lowValue: number
|
||||
): number {
|
||||
return ((highValue << 4) | lowValue) & 0xff;
|
||||
}
|
||||
|
||||
export function trimBytes(buffer: ArrayBuffer, length: number) {
|
||||
return getFirstBytes(buffer, length);
|
||||
}
|
||||
|
||||
export function getViewOfArrayBuffer(
|
||||
buffer: ArrayBuffer,
|
||||
start: number,
|
||||
finish: number
|
||||
) {
|
||||
const source = new Uint8Array(buffer);
|
||||
const result = source.slice(start, finish);
|
||||
|
||||
return result.buffer;
|
||||
}
|
||||
|
||||
export function concatenateBytes(...elements: Array<ArrayBuffer | Uint8Array>) {
|
||||
const length = elements.reduce(
|
||||
(total, element) => total + element.byteLength,
|
||||
0
|
||||
);
|
||||
|
||||
const result = new Uint8Array(length);
|
||||
let position = 0;
|
||||
|
||||
const max = elements.length;
|
||||
for (let i = 0; i < max; i += 1) {
|
||||
const element = new Uint8Array(elements[i]);
|
||||
result.set(element, position);
|
||||
position += element.byteLength;
|
||||
}
|
||||
if (position !== result.length) {
|
||||
throw new Error('problem concatenating!');
|
||||
}
|
||||
|
||||
return typedArrayToArrayBuffer(result);
|
||||
}
|
||||
|
||||
export function splitBytes(
|
||||
buffer: ArrayBuffer,
|
||||
...lengths: Array<number>
|
||||
): Array<ArrayBuffer> {
|
||||
const total = lengths.reduce((acc, length) => acc + length, 0);
|
||||
|
||||
if (total !== buffer.byteLength) {
|
||||
throw new Error(
|
||||
`Requested lengths total ${total} does not match source total ${buffer.byteLength}`
|
||||
);
|
||||
}
|
||||
|
||||
const source = new Uint8Array(buffer);
|
||||
const results = [];
|
||||
let position = 0;
|
||||
|
||||
const max = lengths.length;
|
||||
for (let i = 0; i < max; i += 1) {
|
||||
const length = lengths[i];
|
||||
const result = new Uint8Array(length);
|
||||
const section = source.slice(position, position + length);
|
||||
result.set(section);
|
||||
position += result.byteLength;
|
||||
|
||||
results.push(typedArrayToArrayBuffer(result));
|
||||
}
|
||||
|
||||
return results;
|
||||
}
|
||||
|
||||
export function getFirstBytes(data: ArrayBuffer, n: number) {
|
||||
const source = new Uint8Array(data);
|
||||
|
||||
return typedArrayToArrayBuffer(source.subarray(0, n));
|
||||
}
|
||||
|
||||
// Internal-only
|
||||
|
||||
export function _getBytes(
|
||||
data: ArrayBuffer | Uint8Array,
|
||||
start: number,
|
||||
n: number
|
||||
) {
|
||||
const source = new Uint8Array(data);
|
||||
|
||||
return typedArrayToArrayBuffer(source.subarray(start, start + n));
|
||||
}
|
Loading…
Add table
Add a link
Reference in a new issue