How Beeper Mini Works – Beeper Weblog

We’ve written this weblog put up that can assist you perceive how Beeper Mini works. At Beeper, we consider that it’s vital for you to have the ability to belief the software program that you just use, particularly one thing as essential and delicate as your chat app. We work to earn and maintain your belief in 3 ways:

1. Transparency – since we began Beeper 3 years in the past, we’ve been taking alternatives like this to elucidate how Beeper works. We’ve got a proud historical past of constructing merchandise, like Pebble, and stand publicly behind our work.

2. Open supply – every main piece of software program that we’ve constructed to work together with different chat networks is open supply at github.com/beeper.

3. Privateness and security-aligned enterprise mannequin – we make nice software program and cost a small subscription price. Easy as that. No advertisements. Your information stays non-public.

Learn all the put up for the complete story. TLDR: the next options of Beeper Mini be certain that all communication is encrypted and safe.

• All messages are end-to-end encrypted earlier than being despatched. Beeper (and Apple) can’t see your messages.

• Encryption keys by no means go away your system.

• Beeper Mini connects on to Apple servers. There isn’t a Mac server relay, like different apps.

• No Apple ID is required. Beeper doesn’t have entry to your Apple account.

• Your contact record by no means leaves your system.

Don’t consider that is potential? Attempt the open-source Python proof of concept by yourself laptop to see for your self. Safety researchers are invited to confirm all claims that we make, see appendix under.

Beeper Mini works in a different way than Beeper Cloud in essential ways in which enhance your privateness and safety. Beeper Mini is a standalone Android app. It doesn’t require a cloud server to ship and obtain messages. It additionally implements Apple’s end-to-end encryption protocol natively throughout the Android app itself. All messages are end-to-end encrypted earlier than they’re transmitted straight out of your system to Apple servers. Study extra about iMessage encryption on Apple Platform Security web page.

That is now potential as a result of the iMessage protocol and encryption have been reverse engineered by jjtech, a safety researcher. Leveraging this analysis, Beeper Mini implements the iMessage protocol domestically throughout the app. All messages are despatched and acquired by Beeper Mini Android app on to Apple’s servers. The encryption keys wanted to encrypt these messages by no means go away your cellphone. Neither Beeper, Apple, nor anybody besides the supposed recipients can learn your messages or attachments. Beeper doesn’t have entry to your Apple credentials.

We constructed Beeper Mini by analyzing the site visitors despatched between the native iMessage app and Apple’s servers, and rebuilding our personal app that sends the identical requests and understands the identical responses. Study extra by studying jjtech’s weblog put up, iMessage Explained, and his proof-of-concept Python implementation on Github. Anybody can obtain this code, run it on any laptop that helps Python, login to their iMessage account, and ship and obtain iMessage protocol messages. No Apple {hardware} required.

One other change is that Beeper Mini doesn’t use the Matrix protocol, encryption or code like Beeper Cloud. It’s a fully new codebase, versus our first Android app, which was a fork of Element. Sooner or later, we’re planning so as to add Matrix community assist again in, together with assist for the 15 different chat networks in Beeper Cloud. Learn extra about our roadmap.

Whenever you first begin the Beeper Mini app and register with Google, a registration request is distributed to our Beeper API Server. This service solely exists to confirm your subscription standing, in addition to give our assist staff the knowledge they should debug any points that you could be be operating into (together with your title and electronic mail deal with). No iMessage credentials or messages are transmitted by means of these servers, that are for Beeper Mini account administration solely.

After that, you might be prompted to permit notifications, which sends a push token to Beeper Push Notification service, which permits our servers to ship push notifications to your Android system. These push notifications don’t comprise the contents of messages.

Subsequent, you might be prompted to grant contact record and SMS permission entry.

• Contact record entry is used to match cellphone numbers to contact names, and show profile footage. Your contact record is rarely despatched to Beeper servers.

• SMS entry is used to ship an SMS textual content message out of your quantity to Apple’s “Gateway” service. The gateway sends a response through SMS, and the contents from that SMS response are despatched to Apple to register your cellphone quantity as a blue bubble. Your SMS chat historical past can be used to find out if any of your latest SMS chats have been with individuals who have iPhones. In that case, these chats are proven within the inbox.

It’s at this level that the app generates encryption keys which can be used for end-to-end encrypted messaging. The general public secret is despatched to Apple servers, and the non-public keys are saved within the Android system native filesystem. Beeper Mini is now signed in.

Optionally, you may additionally register to your Apple ID to allow sending/receiving out of your electronic mail deal with. This may also allow you to ship and obtain messages from different Apple gadgets like iPad or Macs. The Apple ID login sends your username, password and a 2-factor code utilizing encrypted HTTPS requests on to Apple servers.

Apple’s iMessage protocol works over Apple Push Notification service, which most builders could be acquainted because the service that permits them to ship push notifications to their iOS functions. For iMessage protocol, all messaging site visitors flows over this service in each instructions, encrypted with keys generated domestically on every system. Beeper Mini connects to APNs over TCP, utilizing the credentials generated in the course of the login course of.

A persistent connection to APNs is required to be notified of recent incoming messages in real-time. On an iPhone, an APNs connection is maintained by the working system, and linked always. In Beeper Mini, the connection can solely be maintained when the app is operating, since Android doesn’t assist APNs natively.

To work round this limitation, we constructed Beeper Push Notification service (BPNs). BPNs connects to Apple’s servers in your behalf when Beeper Mini Android app isn’t operating. We will do that whereas preserving consumer privateness due to Apple separating the credentials wanted to connect with APNs to ship and obtain content material (the “push” credentials) and the keys wanted to encrypt and decrypt messages (the “identification” keys). Push credentials will be shared securely with the Beeper Push Notification service, and BPNs can hook up with APNs in your behalf. Every time BPNs receives an encrypted message that it received’t have the ability to decrypt, it merely disconnects from APNs and sends an FCM push notification to get up the Android app, which then connects to APNs, downloads, decrypts and processes the incoming message. BPNs can solely inform when a brand new message is ready for you – it doesn’t have credentials to see or do anything.

BPNs might be notified whenever you obtain a message, however with out the encryption keys it will possibly’t decrypt something BPNs receives. Additionally, with out the identification credentials, BPNs can’t ship messages in your behalf. For those who don’t thoughts not receiving real-time push notifications for brand spanking new messages, your BPNs will be disabled fully by going to Settings → Handle Connection → Allow Push.

Whenever you create a brand new chat, the cellphone quantity or electronic mail deal with of your supposed recipient is transmitted to Apple servers. If the contact is on iMessage, a public secret is returned.

Sending messages is even less complicated. Whenever you hit ship, the message is encrypted with the general public keys of the supposed recipients and despatched on to Apple servers through an SSL encrypted TCP connection over APNs.

Beeper Mini connects to a couple different companies as a part of its operation. We use a self-hosted set up of Rudderstack (https://rudderstack.beeper-tools.com) for analytics and diagnostic occasions, which we use for bettering the app however will be disabled in Settings → Preferences →Share Diagnostics. We use OneSignal to ship training and account associated push notifications, and RevenueCat to assist combine Google Play subscriptions.

Aside from that, that’s it! No different servers or companies are used. Beeper Mini retains your messaging safe by protecting all messaging credentials, keys, messages and media native to your cellphone, and solely sends them on to Apple’s servers after encrypting them with iMessage’s end-to-end encryption algorithm.

We worth, really, we treasure suggestions. For those who run right into a bug or have a function request, there’s a button in-app to report an issue. We learn each single report.

See Also

Open supply e mail pioneer Roundcube joins the Nextcloud household

Brad Murray and Eric Migicovsky
Beeper cofounders

To write down this weblog put up, we carried out a crimson staff evaluation on our personal app. We made intensive use of the wonderful mitmproxy venture to seize the community site visitors coming from an actual cellphone operating a modified model of the Beeper Mini consumer. A modified model was wanted for this evaluation so as to disable certificates pinning, in order that the Beeper Mini Android app would settle for being linked to mitmproxy as an alternative of solely accepting Apple’s certificates for that connection. If researchers would really like a duplicate of this model of Beeper Mini (with cert pinning disabled) to carry out the same evaluation, please contact us at security@beeper.com.

Beneath is a seize of the requests that we make with Apple’s servers over HTTPS when logging into iMessage along with your cellphone quantity. We first register with a service named albert.beeper.com, which units up our “push” credentials and permits us to connect with APNS. We then make two requests to get the quantity we have to ship an SMS to register our cellphone quantity which is totally different for every service (This seize was taken with a tool registered with Rogers, a Canadian mobile phone service 🇨🇦). Lastly, we take the contents of the response SMS (not proven right here) and ship it to identification.ess.apple.com, registering our account with iMessage and producing the “identification” credentials we’ll use to ship and obtain.

Optionally, you may also register your Apple ID with Beeper Mini as effectively, as proven on this seize. You first present your username and password over encrypted HTTPS on to Apple’s servers, adopted by a second request to supply your 2FA code. We will then register for iMessage once more, this time offering the certificates from each the sooner cellphone quantity registration and our new Apple ID registration. Registering these collectively in the identical name hyperlinks them collectively, permitting some other system that you just’re logged in along with your Apple ID to ship and obtain with each your Apple ID emails and your cellphone quantity.

Subsequent, a seize of the keys shared with the Beeper Push Notification sevice (hostname imux.beeper.com). Observe, the RSA non-public key on this request is your “push” credentials that mean you can hook up with APNs, not your “identification” credentials that mean you can encrypt and decrypt iMesssages. Push credentials can’t be used to escalate permissions or entry something aside from the presence of a brand new APNs push notification. Take a look at [apns.py](<http://apns.py>) in pypush PoC to be taught extra about push credentials.

Sending and receiving isn’t proven right here, as they aren’t finished over HTTP however as an alternative by means of an SSL encrypted TCP connection to APNs. The APNs servers are hosted at *-[courier.push.apple.com](<http://courier.push.apple.com/>) , the place the asterisk is changed by a quantity between 1 and 30. All message contents and media are encrypted along with your “identification” keys, which by no means go away your Android cellphone.

There’s a /login endpoint on Beeper servers, however as talked about earlier, that is just for subscription administration functions. The consumer submits the token acquired from the Google login course of to our servers, and the response accommodates their subscription standing. No iMessage credentials are ever despatched to Beeper servers.

Observe: Beeper and Beeper Mini are fully unbiased software program merchandise, with no relationship to, or endorsement by, Apple, Google, or some other supported chat networks.

iMessage, Apple, Mac and iPhone are logos of Apple, Inc.

Android is a trademark of Google, LLC.