Changelog

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1.0.1 - 2026-09-21

Fixed

  • Link the README's documentation list to HexDocs and its security policy to the repository. The hex.pm package page rewrites repository-relative links into tarball previews, so those entries served raw markdown and the security policy link returned 404.

1.0.0 - 2026-09-21

Decibel 1.0 establishes its first stable public API, strengthens protocol-boundary validation, and documents a safer integration contract. The project remains unaudited and has not been declared production-ready; see the security posture.

Added

  • Add Decibel.ReplayWindow, a pure bitmap replay helper for application-owned connectionless state, with executable guidance for ordered, lossy in-order, and lossy reordered transports.
  • Publish a Getting Started guide with runnable NN and IK examples, application framing, remote-key trust validation, and focused recipes for keys, PSKs, handshake payloads, channel binding, rekeying, fallback, connectionless delivery, session cleanup, and error handling, alongside dedicated security, Noise Pipes, connectionless transport, and 1.0 upgrade guides.
  • Publish the supported Noise r34 patterns, modifiers, primitives, and runtime combinations, together with safe-use guidance for peer authentication, key and PSK handling, negotiation, framing, replay protection, rekeying, and failure handling.
  • Add a security policy with private vulnerability reporting and a latest-release support policy.
  • Add stable, machine-readable exception contracts for peer-message failures, nonce failures, discarded one-way directions, and session ownership, lifetime, and phase errors. Rejected operations leave session state unchanged.

Changed

  • Breaking: Require Elixir ~> 1.18 instead of ~> 1.14. Migration: upgrade the application to Elixir 1.18 or later before updating Decibel.
  • Breaking: Make handshake_complete?/1, handshake_hash/1, nonce/2, and remote_key/1 the canonical accessors. Migration: rename calls from is_handshake_complete?/1, get_handshake_hash/1, get_nonce/2, and get_remote_key/1; the 0.2 names remain deprecated aliases until 2.0.
  • Breaking: Replace bare session references with opaque, owner-aware handles and reject cross-process, closed, unknown, and phase-invalid use with Decibel.SessionError. Migration: treat handles as opaque, drop 0.2-era is_reference/1 checks on session values, perform every operation serially in the process that called new/4, call close/1 when finished, and create a new session after the owner exits.
  • Make the raising API contract explicit: data-producing operations return their payload directly, state-only operations return :ok, and rejected operations raise stable exceptions without committing session state.
  • Breaking: Enforce initiator-to-responder transport direction after the one-way N, K, and X handshakes. Migration: only the initiator may encrypt and only the responder may decrypt; choose an interactive pattern when the application needs bidirectional transport.
  • Breaking: Reject attempts to move an outbound transport nonce backwards. Migration: read the next outbound value with nonce/2, leave it unchanged or move it forward only, and keep application-owned replay state when selecting inbound nonces with set_nonce/3.
  • Breaking: Generate a fresh local ephemeral keypair for every ordinary handshake and reject caller-supplied ephemeral keys outside fallback pre-messages. Migration: omit :e and :re for ordinary handshakes and supply them only for their role-specific fallback pre-message within the same Noise Pipes run.
  • Breaking: Enforce Noise's 65,535-byte limit for handshake and transport messages. Transport plaintexts are limited to 65,519 bytes to leave room for the authentication tag. Migration: split larger logical messages and preserve and authenticate Noise message boundaries in application framing.
  • Make connectionless replay protection explicitly application-owned, with a bounded replay-window example that records nonces only after successful authentication and guidance for coordinated rekeying.
  • Correct handshake-hash, Diffie-Hellman keypair, and nonce types so HexDocs accurately describes 32- and 64-byte hashes, stored keypairs, usable nonce bounds, and the reserved exhaustion value.

Removed

  • Breaking: Remove the unsupported custom :registry construction option. Migration: select a supported Noise r34 pattern from Decibel's built-in registry; :swap remains available for interactive fallback handshakes.

Fixed

  • Validate all role-specific static key material, fallback ephemerals, prologue data, and construction options during session creation, raising stable field-level errors before storing session state. Configurations that previously failed later must now provide exactly the key material required by the selected role and fully modified pattern.
  • Reject malformed or non-canonical Noise protocol names, invalid modifier placements, and missing, malformed, or unused pre-shared keys during session creation instead of silently omitting PSK authentication.
  • Return Decibel.DecryptionError with a stable reason for truncated, unauthenticated, or invalid-key peer messages, preserving processed remote keys and leaving session state unchanged.
  • Allow Noise's final usable transport nonce (2^64 - 2) once, then raise Decibel.NonceError on exhaustion; set_nonce/3 now rejects reserved, negative, non-integer, and oversized nonce values without changing session state.

0.2.4 - Jan 22, 2025

  • Update deps
  • Fix compiler errors

0.2.3 - June 6, 2023

  • Fix unused alias warning.

0.2.2 - June 6, 2023

  • Add get_remote_key/1 to the public API.

0.2.1 - June 6, 2023 (Reverted)

  • Add get_public_key/2 to the public API.

0.2.0 - May 19, 2023

  • Breaking change - renamed set_n/3 and get_n/2 to set_nonce/3 and get_nonce/2 respectively
  • AEAD failure now raises a Decibel.DecryptionError rather than a RuntimeError. If this is raised during a handshake, this struct will also contain any remote public keys processed during the handshake, up to the point of failure
  • Added fallback tests
  • Improved documentation around Noise Pipes and connectionless transports

0.1.1 - April 25, 2023

  • Initial revision