Council – Encrypted Messaging

Council is an encrypted calling and messaging app where the conversation keys stay with the people in the conversation. Every network is locked with a passphrase only its members know: your device turns that passphrase into encryption keys using Argon2id, our servers store and relay only ciphertext, and the protocol is designed to resist both today's adversaries and future quantum computers. Your security is as strong as the passphrase you choose.

ENCRYPTED VOICE CALLS

Call the people in your network, one to one or as a group, with end to end encrypted voice. Audio is encrypted frame by frame on your device with keys derived from your network passphrase; the server relays ciphertext it cannot decrypt. Incoming calls ring full screen with Accept and Decline, the way a phone call should.

HOW IT WORKS

Every Council network is locked with a passphrase that only its members know. Your device derives the encryption keys from that passphrase with Argon2id; the server stores and forwards ciphertext and is not part of the key exchange. On top of that, every device holds a unique secret protected by ML-KEM-1024 post-quantum key encapsulation, so a compromised passphrase alone is not enough to decrypt a message: an attacker would also need a secret held on a member's device.

BUILT TO RESIST QUANTUM ATTACK

Every layer of the protocol, including key derivation, key encapsulation, message encryption, and call audio, uses cryptography chosen to resist quantum attack: ML-KEM-1024 for key encapsulation, AES-256-GCM for encryption, and HKDF-SHA-384 for key derivation. There are no elliptic-curve or RSA primitives in the protocol. That matters now, because encrypted traffic can be recorded today and decrypted once the hardware exists.

BURN WHEN DONE

When you burn a Council network, the server deletes the network and its dependent records in one cascade rather than flagging them for a later cleanup, and the key material goes with it. Ciphertext without its keys cannot be decrypted.

YOUR NETWORK IS NOT YOUR CONTACT LIST

You sign in with your phone number, which receives a one-time code and secures your account. Your number is never shown to other members and never used to find contacts or map who you know, and Council doesn't request access to your contact list at all. You join a network by knowing its passphrase. There is no contact-graph import to leak or sell.

NO SIGNATURE TIES A MESSAGE TO YOU

Messages in Council are authenticated within your group but cannot be cryptographically attributed to any individual outside of it. There is no digital signature tying a message to your identity.

KEY FEATURES

• End to end encrypted voice calls, one to one and group
• Incoming calls ring full screen, like a phone call
• Encryption keys created on your device from a passphrase you choose
• Post-quantum cryptography (ML-KEM-1024) in every layer of the protocol
• Burn a network to delete it and its records in one cascade
• No contact-list access; networks are joined by passphrase
• Encrypted media sharing for photos, videos, GIFs, and files
• Device-bound secrets, so a passphrase alone is not enough to decrypt
• No per-person signature: a message can't be pinned on you outside the group

Council Pro unlocks unlimited encrypted networks. Subscribe yearly or redeem a license key.

Privacy Policy: https://councilapp.com/pp Terms of Service: https://councilapp.com/tos Support: https://support.councilapp.com