SureSpot is an Android and iPhone open source app for encrypted end to end chat, you can send pictures and text,nobody can decrypt the messages, not even the app delelopers. AES256 bit encryption keys are created in your phone and the Diffie-Hellman key agreement protocol is used to exchange them securely without having to grant private keys access to a third party, only the person you are communicating with is able to read the messages and view the photos you send.
An spy agency attempting to wiretap Surespot will find that there is not a single server they can attack for mass surveillance, they would have to hack all the end point phones to listen in, this would be impossible to do if Surespot became popular. For further privacy, Surespot can create multiple identities to chat with different contacts, your identity can be backed up, restored or permanently erased and the paranoid person can create new encryption keys as often as needed.
Another nifty feature is that you can delete the messages you have sent from the receiver’s inbox and lock attached images to stop them from being saved outside the app, Surespot also locks itself after a few minutes of inactivity to stop impersonation in case your phone is taken while still on.
Unlike WhatsApp and other privacy invasive chat apps, people in your contact list will not get automatically notified when you install Surespot, before a chat can take place you need to know the nickname of the person you would like to communicate with and that person will have to accept the invitation. The app is free for chat, paying a small fee will add voice messaging so that instead of typing in you can talk to your mic, record a message and send it encrypted to your contact, another tab in the app allows you for an optional Paypal or Bitcoin donation.
This privacy app earned of the highest marks in the Electronic Frontiers Foundation score card, the only downside the EFF highlighted were that Surespot code has not been audited and the possibility of somebody getting access to your phone. The common auditing problem comes down to raising enough money, it is not the developers fault, and the danger of having your phone stolen, it can be partially fixed fully encrypting the phone.
I liked this app a lot, it has all I want from a secure mobile chat app, the most important factors being that Surespot is based on trusted encryption algorithms, it is open source which allows experts to peek in and check for bugs or backdoors, and the app does not use your phone number as a contact, the person you are chatting will not find it out unless you tell him, the only missing feature is that you can’t set up a group chat, which I don’t currently use. I am adding Surespot to my list of favourite apps.