cipher-chat-ca.crt) and your own device certificate
(….p12) with its password. Without them the app can't connect.
Set up on Samsung Galaxy
Other Android phones are similar; search Settings for “certificate” if a menu is named differently.
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Save both files to Downloads
Get them from the server owner in person or over a USB cable or a trusted app. Don't use email.
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Install the CA certificate
Settings → Security and privacy → More security settings → Install from device storage → CA certificate. Tap Install anyway, confirm with your PIN, and pick
cipher-chat-ca.crt.This lets your phone recognise the server, so there's no security warning.
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Install your device certificate
Same menu → VPN and app user certificate → pick your
.p12file → enter its password → name it Cipher Chat.This is your key to get in. The server refuses every phone that doesn't have one.
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Enter the server address
When Chrome asks which certificate to use, pick Cipher Chat. If it asks to access devices on your network, tap Allow.
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Install the app
Use the Install app button at the top, or in Chrome tap ⋮ → Add to home screen → Install. It then lives in your app drawer like any other app.
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Create your username and check safety numbers
Pick a username. When you open a chat, tap Verify safety number and compare the number with your contact in person or on a call. If it matches, nobody can be listening in.
Something not working?
- “Can't reach the server”
- Check the address (it can change; ask the owner for the latest), that the server phone is on, and that both certificates are installed.
- Chrome never asked for a certificate
- Close Chrome completely (swipe it away in Recents) and open the link again.
- Picked the wrong certificate
- Chrome → ⋮ → Settings → Site settings → All sites → find the server → Clear & reset, then reload.
- Lost or replaced your phone
- Tell the server owner so they can block the old device and give you a new certificate.
How your messages stay private
- Scrambled on your phone. Each message is locked with a fresh key that only the receiver's phone can unlock.
- Scrambled again on the way. The connection itself is encrypted, so anyone tapping the network sees gibberish.
- The server can't read them. It only passes along scrambled messages and never stores them.
- Invite only. Phones without a device certificate can't even connect.