Alternatives to SMS Text Messages

Thursday, October 3, 2013

TL;DR:

  • Text messages are unreliable and insecure
  • Apple iMessage and Google+ Hangouts suffice in most situations
  • Off-the-Record messaging provides personal encryption on top of Google and Facebook services

Many of us use SMS for text messaging, but have had some trouble with delayed or lost messages. Text messages are inherently unreliable and insecure. Because our work often involves confidential information, we need to consider the limitations of our favorite communication channel.┬áMany of you know that I’m technically oriented. As a software developer with mobile technology experience, I’d like to start by explaining how text messages work.

Cell phone networks carry voice traffic. To prevent interference among conversations, there’s a small side channel for traffic control signals, tiny messages that help regulate the voice traffic.

Traffic control signals are only really useful when there’s traffic. In 1984, two clever network engineers, Friedhelm Hillebrand and Bernard Ghillebaert, figured out how to repurpose the control channel, during downtime, for text messages. It works with existing infrastructure and is essentially free, but they could charge 10 cents/message.

Most of the time, it works pretty well. The problem arises when there’s a lot of voice traffic. Text messages could be put on hold on the order of seconds, minutes, or hours. Some are dropped entirely.

Sender identity is another issue. Text messages are similar to snail mail and email in that the sender sets the return address (phone number). This is often abused. And when we exchange confidential information, we really need to know who we’re talking to.

If you have a smartphone with a data plan, you might have tried iMessage or Google Talk (now known as Hangouts). They’re far superior to regular text messages, and are good enough in most situations.

There’s still the possibility that Apple or Google might examine or store our messages for their own purposes. If that’s a problem, we could take privacy into our own hands with Off-the-Record messaging, a system for encoding messages so that only the intended recipients could decode them. It works with many platforms, and could be used with Google and Facebook.

There’re a couple of potential pitfalls. The app needs to be running for you to decode messages, which could use additional battery power. I like to start a conversation using other channels, then take it off the record as needed. There’s no group messaging support at this time.

Let’s all think about what we could do to protect our privacy.

One Comment

  1. mateor says:

    Hey Jiang!

    Let me recommend TextSecure from WhisperSystems. Already in Play Store for Android, but will be available for iOS pretty soon. I have nothing to do with the project, but have admired it from afar. Hope you’re well.

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