Are Text Messages Encrypted Over WiFi? 11 Apps + 3 Critical Factors


Did you send a private text message that you’re afraid someone else might read? A lot of people think being connected to Wi-Fi means your texts are secure. But, are text messages encrypted over WiFi?

Regular SMS text messages are not encrypted and go over the cellular network voice channel. Most messenger apps only encrypt texts while sending them over WiFi or mobile data. The service can access messages. The most secure apps use end-to-end encryption, so only recipients can read them.

Being on WiFi does not automatically guarantee a text is transmitted or stored encrypted.

On a smartphone, which messenger app you use determines how secure your texts are.

Mike Chu

The following list of the most popular messaging apps summarizes how each service handles your messages.

11 Messenger Apps: Can Someone See Your Text Messages?

Messenger apps each use different ways to transmit and store texts. Some services switch between insecure SMS and WiFi or mobile data like iMessage and Android Messages. The best way to ensure your message is protected from your school, employer, or service provider is to use an end-to-end encrypted messenger.

If you’re concerned someone other than your recipient might see your text messages, use an app from lower on this list. These messaging services send encrypted text messages with the most privacy.

App/ServiceEncryptionSent ViaService Readable
Android
Messages
None/Clear TextCellular NetworkYes
iMessage
with non-iMessage Users
(green text bubbles)
None/Clear TextCellular NetworkYes
TalkatoneOnly While SendingWiFi/Mobile DataUnknown
LINEEnd-to-End (partial)WiFi/Mobile DataUnknown
Facebook
Messenger
Only While Sending 1WiFi/Mobile DataYes1
iMessage
with other iMessage Users
(blue text bubbles)
End-to-EndWiFi/Mobile DataNo
ViberEnd-to-EndWiFi/Mobile DataNo
WhatsappEnd-to-End
with non-default Expiration
WiFi/Mobile DataNo
SnapchatEnd-to-End
with Expiration
WiFi/Mobile DataNo
TelegramEnd-to-End
with Expiration
WiFi/Mobile DataNo
SignalEnd-to-End
with Expiration
WiFi/Mobile DataNo
BriarEnd-to-EndTor (WiFi/Mobile Data), BluetoothDecentralized
1 unless using non-default Secret Conversation mode

3 Critical Privacy Factors

The columns in the above table represent the three critical factors to your text message privacy on your mobile device.

Encryption

This column describes how well your text messages are protected using encryption.

  1. None/Clear Text: Texts are sent in plain text and are most vulnerable. Anyone can read texts that are stored unencrypted.
  2. Only While Sending: Texts are encrypted only in transit. Transport encryption protects them from being read while moving across the Internet. They are otherwise stored in plain/cleartext.
  3. End-to-End: Texts are encrypted and decrypted only when the recipient receives them.
  4. End-to-End with Expiration: Texts are end-to-end encrypted and destroy themselves after a given amount of time. This encryption method is best for privacy.

Sent Via

  1. Cellular Network: Texts are sent through the voice channel of your cellular service and sometimes count against a limited messaging plan.
  2. WiFi/Mobile Data: Texts are moved through your local WiFi or mobile data connection.
  3. Bluetooth: Texts are transmitted between two devices in close range, less than 100 meters or 328 feet.
  4. Tor (WiFi/Mobile Data): Texts are wrapped in a data connection that travels through three random, anonymous nodes, each unaware of the contents of the inner encrypted data. This sending method is best for privacy.

Here’s a short explainer video (1m12s@2x) about The Onion Router (Tor) network.

Service Readable

  1. Yes: Texts are logged and can be viewed by the service provider. Metadata like recipients, date and time, etc. are also available.
  2. Unknown: Texts are potentially logged as plain text, or the service can decrypt content when compelled by law enforcement. Company documentation or national law is unclear.
  3. No: Texts are not read by the service. Metadata like sender and recipient, timestamps, message length, etc. might be kept for a varying amount of time.
  4. Decentralized: Texts do not have a centralized service provider. They are sent peer-to-peer over available data connections. This service method is best for privacy.

How To Know If You’re Going To Text Over WiFi?

Man holding smartphone texting wondering if it's sent over wifi

If you’re ever in doubt of whether your text is going to be sent over WiFi, follow these steps:

  1. Go to Airplane Mode.
  2. Turn back on WiFi.
  3. Now, try sending a test SMS message (text) or MMS message (picture) from iMessage, Android Messages, or whatever default app you’re using
  4. Did the message send successfully?

If the message sent successfully, then you can be certain that your using the Wi-Fi network for text messaging. This test also confirms you’re texting over data when you’re off Wifi and using cellular data.

If the message stays in a waiting state or fails, then you’re using an old, insecure SMS text message. It’s time to move to a more secure messaging app. By switching, you’ll ensure that your device sends texts over WiFi. Most secure messaging apps include additional features like encrypted WiFi calling and vanishing texts.

Additional Notes

  • Prefer services that allow sign up without a phone number and instead use login credentials.
  • Go with messaging services that do not use your contact list to help link accounts.
  • Projects that are open source provide greater security and transparency to guard against security holes.
  • Some of these services include encrypted calling which you can use instead of standard calls on your mobile phone plan.
  • Messaging apps that include voice and encrypted video calls can cut down costs on your cell phone plan.
  • Use trusted WiFi whenever possible to avoid linking data usage with your phone number and higher charges for data rates.
  • No messaging service or app is hack-proof. Choose one that fits your privacy level to send encrypted texts.

Final Word

Remember that being connected to Wi-Fi does not automatically mean your text messages are inaccessible by other people. You need to know and trust the technology behind the messaging app you’re using.

This video (5m7s@2x) walks you through an easy set of questions to answer when selecting a secure messaging app.

Mike Chu

Mike is a web developer and content writer living as a digital nomad. With more than 20 years of devops experience, he brings his "programmer with people skills" approach to help explain technology to the average user. Check out his full author bio by clicking here.

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