Frozen Chat vs Signal

If you are reading this, you probably already know Signal. It is the messenger that made strong end-to-end encryption normal, and its protocol now protects billions of conversations in other apps too. Frozen Chat uses the same library for one-to-one chats, libsignal, unchanged. So this is not a comparison between “secure” and “insecure”: both encrypt everything by default and neither company can read your messages.

The differences are about everything around the encryption: what you need to sign up, how you find people, how groups are built, how the service is paid for, and which devices you can use today. The table below sums it up, and the sections after it explain each point and where Signal is the better choice.

The biggest difference: your phone number

Signal needs a phone number to register. Since 2024 you can set a username and hide your number from people you chat with, which is a real improvement, but the account is still tied to a number that Signal verifies by SMS or call. In most countries a SIM card is registered to a legal name, so the number links the account to a person at the carrier level, and losing access to the number can complicate getting back in.

Frozen Chat has no phone number field anywhere in the system. You choose a username, solve a small proof-of-work puzzle that slows down spam bots, and enter a licence key. There is no SIM to register, no SMS code, and no e-mail. Read more in a messenger without a phone number and our article on why a messenger shouldn't need your phone number.

Encryption: mostly the same, by design

For one-to-one chats both apps use the Signal protocol: a PQXDH handshake that mixes elliptic-curve keys with a post-quantum ML-KEM key, then the Double Ratchet, which gives every message a fresh key. Both use sealed sender, so the server delivers a message without being told who sent it. Frozen Chat deliberately invents no cryptography of its own; it builds on what Signal published and reviewed.

Groups are where the designs part. Signal runs groups on its own private group system. Frozen Chat uses Messaging Layer Security (MLS, RFC 9420), the IETF standard for group encryption, with a hybrid X25519 + ML-KEM-768 cipher suite, so group keys also get post-quantum protection. Both approaches keep the server out of the group: it never holds group keys. Our security page lists exactly what our server can and can't see.

Finding people and contact lists

Signal can match your address book against registered phone numbers to show which contacts use Signal. It does this carefully, inside a secure hardware enclave, and you can decline. Frozen Chat never asks for your address book at all: you add people by username or by scanning their QR code. That makes the first step a little slower (you have to tell friends your username), and in exchange there is nothing about your social graph to upload.

Paying vs free

Signal is free and run by a nonprofit foundation funded by donations. That is a genuine strength: anyone can install it at no cost. Frozen Chat is paid. Plans are one-time licence keys bought with cryptocurrency on our pricing page, with no name, e-mail or account needed at checkout, and nothing renews automatically. Paying for the service is what lets us run it without ads, data deals or tracking, and the crypto checkout means the payment doesn't tie the account to a bank card.

Where Signal is the better choice

• You want it free. Signal costs nothing; Frozen Chat needs a licence key.
• You need iPhone or desktop apps today. Signal has apps for iOS, Windows, macOS and Linux. Frozen Chat is on Android with a web app linked to your phone, and iOS is coming soon.
• Your contacts are already there. Signal has a much larger network, and address-book matching makes it easy to find them.
• Track record and openness. Signal's client and server code is public and its protocol has been studied by academic researchers for over a decade.

Where Frozen Chat is the better choice

• You don't want a phone number on the account at all, not even a hidden one.
• You want to pay without a card and keep the purchase separate from your identity.
• You want post-quantum protection for groups too, through MLS with a hybrid suite.
• You share secrets outside the app. Private notes give you a link that opens once in any browser and then self-destructs, with the key kept out of our reach.

Known limits on our side

We prefer to say this plainly. The first contact with someone is trust-on-first-use until key transparency is added (compare safety numbers for people who matter, as you would on Signal). The web app is lower assurance than the phone app, because a browser runs the code a server sends. Both points are on our security page.