Novolis.Messaging.SecureText 2026.1.1.47

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Novolis.Messaging.SecureText

Transport-neutral message envelopes and endpoint sessions for secure-text v1.

Install

dotnet add package Novolis.Messaging.SecureText

What this package provides

• Canonical binary SecureTextEnvelope serialization.
• Header authenticated data that binds routing, timestamp, key epoch, and counter.
• A bounded replay window and persistable counter state.
• SecureTextSession to protect and open UTF-8 text at endpoints.
• SecureTextGroupId and deterministic group-scoped pair conversation derivation for ciphertext-per-recipient group delivery.

The relay transports serialized envelopes as opaque bytes. It may validate size and routing fields, but it does not decrypt content.

Usage

using Novolis.Messaging.SecureText;
using Novolis.Security.SecureText;

var localIdentity = SecureTextDeviceIdentity.Create();
var localBundle = SecureTextPublicBundle.Create(localIdentity);
var trustedPeer = new SecureTextTrustedPeer(peerBundle);

using var session = new SecureTextSession(
    localIdentity,
    localBundle,
    peerBundle,
    trustedPeer,
    SecureTextConversationId.New());

var envelope = session.Protect("authenticated text");
byte[] wireBytes = SecureTextEnvelopeCodec.Serialize(envelope);

Persist session.State.Snapshot() before sending and after each successful receive. A reset counter weakens replay protection. Store private identities with a protected implementation of ISecureTextKeyStore; never place them in an ordinary file or configuration.

Approved group profile

SecureTextConversationId.DeriveForGroupMember(groupId, localDevice, peerDevice) derives a separate conversation and key scope for one sender/recipient copy inside a group membership epoch. The application sends one independently authenticated ciphertext to every approved recipient; it does not share a symmetric group key. The group id is therefore bound through the derived conversation id and authenticated envelope header.

Membership approval, roster delivery, and rekeying are transport/application responsibilities. Treat every membership change as a new group id and obtain explicit approval from every device before sending to that roster.

Limits

Secure-text v1 provides pairwise cryptographic sessions. Its approved group profile is pairwise fan-out, not sender keys or an MLS implementation. It is not an audited ratchet protocol and makes no forward-secrecy or post-compromise-security claim.