Guide
A private messenger: what Sika protects, and what it does not
Privacy claims are easy to make. Here is what Sika does, in plain words, including the parts that are not hidden.
What is end-to-end encrypted
Private chats, files and calls are locked on your phone and unlocked only on the other person's phone. The keys are made on your phone and stay under your control; a backup, if you make one, is locked with a code only you hold. Sika's servers carry the locked messages. They cannot read a message, open a file or listen to a call. Nothing in Sika is built with homemade cryptography: it uses well-known, reviewed libraries.
What servers still see
- If you sign up with a phone number or email, Sika knows that account exists. It does not know what you say.
- The relay that carries messages can see who mails whom, when, and how big the message is. It does not see the content.
- Public content, such as channels and halls, is public and stored on our servers. It is labelled public and kept separate from private chats.
- Orders in SikaPay keep the order's state so the payment and delivery steps can work.
What you control
- A PIN lock on the app, and safety numbers to check that you are talking to the right person.
- Disappearing messages for a chat, and deleting a message for everyone on your own messages.
- An encrypted backup that only you can open, so a lost phone does not mean lost chats. If you forget the backup code, nobody can reset it for you.
Checking us
Our Security page says how to report a problem, and the Privacy Policy lists every kind of data we keep, why, and for how long.
Questions people ask
Can Sika read my private chats?
No. They are end-to-end encrypted, and the keys stay on your phone and the other person's phone.
Do I need a phone number?
No. You can sign up with a phone number or an email, and find friends from your contacts, but the app also works with only a name and a key.
What if I lose my phone?
Make an encrypted backup in Settings, then restore it on the new phone. Without a backup, the old chats cannot be recovered.
Try it
Sika is in early access and runs on Android 7 and later. Download Sika, or read how we protect your chats on the Security page. More help is in the Help Centre.