namespace channel {
    string new_double_ratchet([ByRef] sequence<u8> session_key, [ByRef] sequence<u8> sending_header_key, [ByRef] sequence<u8> next_receiving_header_key, boolean is_sender, [ByRef] sequence<u8> sending_ephemeral_private_key, [ByRef] sequence<u8> receiving_ephemeral_key);
    DoubleRatchetStateAndEnvelope double_ratchet_encrypt(DoubleRatchetStateAndMessage ratchet_state_and_message);
    DoubleRatchetStateAndMessage double_ratchet_decrypt(DoubleRatchetStateAndEnvelope ratchet_state_and_envelope);

    TripleRatchetStateAndMetadata new_triple_ratchet([ByRef] sequence<sequence<u8>> peers, [ByRef] sequence<u8> peer_key, [ByRef] sequence<u8> identity_key, [ByRef] sequence<u8> signed_pre_key, u64 threshold, boolean async_dkg_ratchet);
    TripleRatchetStateAndMetadata triple_ratchet_init_round_1(TripleRatchetStateAndMetadata ratchet_state_and_metadata);
    TripleRatchetStateAndMetadata triple_ratchet_init_round_2(TripleRatchetStateAndMetadata ratchet_state_and_metadata);
    TripleRatchetStateAndMetadata triple_ratchet_init_round_3(TripleRatchetStateAndMetadata ratchet_state_and_metadata);
    TripleRatchetStateAndMetadata triple_ratchet_init_round_4(TripleRatchetStateAndMetadata ratchet_state_and_metadata);
    TripleRatchetStateAndEnvelope triple_ratchet_encrypt(TripleRatchetStateAndMessage ratchet_state_and_message);
    TripleRatchetStateAndMessage triple_ratchet_decrypt(TripleRatchetStateAndEnvelope ratchet_state_and_envelope);
};

dictionary DoubleRatchetStateAndEnvelope {
  string ratchet_state;
  string envelope;
};

dictionary DoubleRatchetStateAndMessage {
  string ratchet_state;
  sequence<u8> message;
};

dictionary TripleRatchetStateAndMetadata {
  string ratchet_state;
  record<string, string> metadata;
};

dictionary TripleRatchetStateAndEnvelope {
  string ratchet_state;
  string envelope;
};

dictionary TripleRatchetStateAndMessage {
  string ratchet_state;
  sequence<u8> message;
};