GLOSSARY.md

Glossary

Keys and identities

• LTIK (Long-Term Identity Key)
  • Root identity key used to authenticate a user/device identity over longer periods.
• MTSK (Medium-Term Signing Key)
  • Operational signing key authorized by the LTIK.

Sessions and ratchets

• Handshake
  • The initial protocol that authenticates peers and establishes a shared secret.
• Double Ratchet
  • A key schedule that evolves keys over time to provide forward secrecy and post-compromise recovery.
• Chain Key (CK)
  • A symmetric secret that is advanced to derive per-message keys.
• Message Key (MK)
  • A one-time key used with an AEAD (e.g., ChaCha20-Poly1305) to encrypt one message.

Network

• Relay node
  • A mesh participant that forwards encrypted cells hop-by-hop.
• Mailbox node
  • A node that temporarily stores encrypted payloads for offline recipients.

Threats

• MITM (Man-in-the-middle)
  • An attacker intercepts and modifies traffic between two parties.
• Replay attack
  • An attacker re-sends valid old messages to cause confusion or state rollback.
• Sybil attack
  • An attacker runs many identities/nodes to gain disproportionate influence.