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Oct 13, 2026 · 4 min read

Can quantum computers read my text messages?

Four thick chat bubbles drawn in white dots, alternating left and right like a conversation and stepping toward the viewer, each with a front face, a back face and an edge. The lines of text in the third bubble are drawn as rings instead of dots.

Most of us have years of private conversations sitting in our phones, and most of us assume they’re private because the app says they’re encrypted. So when people hear that quantum computers will one day break today’s encryption, they want to know whether someone will be able to read all of it.

No quantum computer can read your messages today. When one can, it still won’t be reading yours, because the average person’s messages won’t be worth the time. The reason comes down to how a messaging app keeps a conversation private in the first place, and which part of that a quantum computer could attack.

How a messaging app keeps your chats private

Apps like WhatsApp lock each message so that only the phones in the conversation can read it. Not even the company running the app can see what you wrote. This is called end-to-end encryption.

The lock needs a key, and both phones need the same one. Before the first message, the two phones agree on a secret key by swapping some numbers over the internet, and most apps do that using a method called elliptic-curve cryptography. The clever part is that someone who records the swap still can’t work out the key from it, at least with an ordinary computer.

A large enough quantum computer changes that. It could take a recording of the swap, work out the key, and unlock the messages that key protects. The newer post-quantum methods agree on keys in a different way, and nobody knows a way for a quantum computer to work those keys out. Some apps have already added them.

Signal and iMessage are protected, but most other apps aren’t yet

Which messaging apps are protected against future quantum computers, as of October 2026.

  • SignalProtected since September 2023
  • iMessageProtected since March 2024The blue bubbles on an iPhone.
  • WhatsAppNot protected yetMeta, which owns it, hasn't announced a date.
  • Facebook MessengerNot protected yet
  • Google MessagesNot protected yetIncluding chats between iPhones and Android phones.
  • TelegramNot protected yetOrdinary chats aren't end-to-end encrypted at all, so Telegram itself can read them today. Its optional Secret Chats are end-to-end encrypted, but not protected against quantum computers.

One kind of message is missing from that list, because it has no lock for a quantum computer to break: the plain text message.

Plain text messages can already be read without a quantum computer

A text sent as SMS, which shows up as a green bubble on an iPhone, isn’t end-to-end encrypted. It passes through your phone company’s computers in a form those computers can read.

That would matter less if phone companies were impossible to break into, but in 2024, hackers working for China’s government broke into AT&T, Verizon and other US phone companies, and could read some calls and texts as they were being sent. Among the systems they reached were the ones phone companies built so that police can tap a phone when a court orders it. The door built for the police turned out to work just as well for foreign spies.

Afterward, the FBI advised Americans to use encrypted messaging apps. That advice had some history behind it. For years, the FBI had asked Apple and other tech companies to build a similar way in for police into their encrypted apps. The companies refused, arguing that any way in for police would also be a way in for criminals and foreign spies, which is roughly what had just happened to the phone companies.

So a quantum computer makes no difference to SMS. Anyone who can get into a phone company’s systems can already read your texts.

Even a future quantum computer could break only about 26,000 keys a year

Encrypted apps are much harder to read in bulk. Even once a quantum computer can work out these keys, it can only do so one key at a time, and apps keep switching to new keys during a conversation. Each new key has to be broken separately, so reading the whole of someone’s chat history would mean breaking many keys.

How long does one key take? In 2026, Google researchers estimated that a quantum computer with under 500,000 qubits could work out one of these keys in about 20 minutes. No such machine exists yet: the largest today has about 1,100 qubits. Suppose one did exist and ran day and night all year. At three keys an hour, it would break about 26,000 keys a year. WhatsApp alone has more than 3 billion users.

The first machines able to do this will be rare and very expensive, and their owners will spend that time on governments, armies and large companies. Your group chat about who’s bringing what to the barbecue is not on the list.

The person most likely to read your old messages is whoever goes through your phone after you die. Apple and Google both let you choose that person in advance.

People whose messages will still matter in twenty years should switch now

There is one group for whom the timing matters, and it comes down to how governments collect information. Some governments record encrypted internet traffic and store it, so that they can unlock it once they have a quantum computer that can. This is called harvest now, decrypt later.

It means a message sent today on an unprotected app could be read years from now. Switching apps later doesn’t help, because the recording of the old message already exists and was locked the old way.

That matters for people whose messages a government would still want in ten or twenty years: journalists and their sources, lawyers, government officials, activists, and people who work in defense. They should use Signal or iMessage for sensitive conversations now. Everyone else will be protected as their apps update.

WhatsApp and Messenger are expected to add the protection well before it’s needed

Apple and Signal have already shown that this protection works in apps used by enormous numbers of people, and the method they use is a free public standard that any company can adopt. The first messages unlocked from old recordings will belong to governments and their officials.

Sources

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