Best texting app for simplicitySo you want to send a short, instant, text-based dispatch to another human. The options are endless -- iMessage, Slack, Instagram, WhatsApp, Skype, Snapchat -- but their security is variable. Short of whispering words into another person's ear, it's difficult to guarantee that no one else will ever be eavesdropping.
For anything you wouldn't want to be seen by your ISP or used against you in a court of law, end-to-end encryption is necessary. It works by giving every user of an app a public key and a private key. Messages sent to you are encrypted with your public key and can only be opened with the private key. To anybody without your private key -- including the app company or a government that comes for the data later -- the text is indecipherable.
Even the privacy nonprofit Electronic Frontier Foundation does not recommend any single messaging app.
Now the choice of medium to send confidential information gets a little more complicated -- so much so that even the privacy nonprofit Electronic Frontier Foundation does not recommend any single messaging app.
Messaging apps only work when the people you want to message are on them. Signal is generally the privacy expert's choice for secure comms, but your aunt might not have it. SMS reaches everyone with a phone number but is largely unsecured. iMessage has end-to-end encryption but is only available on Apple devices. WhatsApp and Facebook Messenger have massive global reach but also share a common liability: Facebook.
top 10 Secret Messaging App
At its core, your choice of app comes down to your specific security situation versus the need for convenience like backups versus who you need to reach.