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101 lines
2.9 KiB
TypeScript
101 lines
2.9 KiB
TypeScript
import { EncryptionType } from '../types/EncryptionType';
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import { SignalService } from '../../protobuf';
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import { UserUtil } from '../../util';
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import { CipherTextObject } from '../../../libtextsecure/libsignal-protocol';
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/**
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* Add padding to a message buffer
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* @param messageBuffer The buffer to add padding to.
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*/
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export function padPlainTextBuffer(messageBuffer: Uint8Array): Uint8Array {
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const plaintext = new Uint8Array(
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getPaddedMessageLength(messageBuffer.byteLength + 1) - 1
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);
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plaintext.set(new Uint8Array(messageBuffer));
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plaintext[messageBuffer.byteLength] = 0x80;
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return plaintext;
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}
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function getPaddedMessageLength(originalLength: number): number {
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const messageLengthWithTerminator = originalLength + 1;
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let messagePartCount = Math.floor(messageLengthWithTerminator / 160);
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if (messageLengthWithTerminator % 160 !== 0) {
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messagePartCount += 1;
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}
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return messagePartCount * 160;
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}
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/**
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* Encrypt `plainTextBuffer` with given `encryptionType` for `device`.
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*
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* @param device The device to encrypt for.
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* @param plainTextBuffer The unpadded plaintext buffer.
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* @param encryptionType The type of encryption.
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* @returns The envelope type and the base64 encoded cipher text
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*/
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export async function encrypt(
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device: string,
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plainTextBuffer: Uint8Array,
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encryptionType: EncryptionType
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): Promise<{
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envelopeType: SignalService.Envelope.Type;
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cipherText: Uint8Array;
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}> {
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const plainText = padPlainTextBuffer(plainTextBuffer);
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const address = new window.libsignal.SignalProtocolAddress(device, 1);
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if (encryptionType === EncryptionType.MediumGroup) {
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// TODO: Do medium group stuff here
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throw new Error('Encryption is not yet supported');
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}
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let innerCipherText: CipherTextObject;
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if (encryptionType === EncryptionType.SessionRequest) {
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const cipher = new window.libloki.crypto.FallBackSessionCipher(address);
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innerCipherText = await cipher.encrypt(plainText.buffer);
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} else {
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const cipher = new window.libsignal.SessionCipher(
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window.textsecure.storage.protocol,
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address
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);
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innerCipherText = await cipher.encrypt(plainText.buffer);
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}
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return encryptUsingSealedSender(device, innerCipherText);
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}
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async function encryptUsingSealedSender(
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device: string,
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innerCipherText: CipherTextObject
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): Promise<{
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envelopeType: SignalService.Envelope.Type;
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cipherText: Uint8Array;
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}> {
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const ourNumber = await UserUtil.getCurrentDevicePubKey();
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if (!ourNumber) {
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throw new Error('Failed to fetch current device public key.');
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}
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const certificate = SignalService.SenderCertificate.create({
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sender: ourNumber,
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senderDevice: 1,
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});
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const cipher = new window.Signal.Metadata.SecretSessionCipher(
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window.textsecure.storage.protocol
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);
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const cipherTextBuffer = await cipher.encrypt(
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device,
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certificate,
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innerCipherText
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);
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return {
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envelopeType: SignalService.Envelope.Type.UNIDENTIFIED_SENDER,
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cipherText: new Uint8Array(cipherTextBuffer),
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};
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}
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