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DTLS In Constrained Environments

Document Charter DTLS In Constrained Environments WG (dice)
Title DTLS In Constrained Environments
Last updated 2015-10-14
State Approved
WG State Concluded
IESG Responsible AD Stephen Farrell
Charter edit AD Stephen Farrell
Send notices to (None)


The Constrained Application Protocol (CoAP) can be used to manipulate resources on a device in constrained environments secured by Datagram Transport Layer Security (DTLS, RFC 6347). The DTLS In Constrained Environments (DICE) working group focuses on supporting the use of DTLS Transport-Layer Security in these environments. Constrained environments looked at in DICE include contrained devices (e.g. memory, algorithm choices) and constrained networks (e.g. PDU sizes, packet loss).

The first task of the working group is to define a DTLS profile that is suitable for Internet of Things applications and is reasonably implementable on many constrained devices.

The second task of the working group is to define how DTLS record layer can be used to transmit multicast messages securely. Security for these multicast messages is needed in many Internet of Things environments, as some messages are commonly multicast among a set of receivers. Session keys are needed in order to use the DTLS record layer in this way. Changes to the DTLS handshake to support this may be needed in future but are not part of the initial charter for DICE wg.

The third task of the working group is to investigate practical issues around the DTLS handshake in constrained environments. Many current systems end up fragmenting messages, and the re-transmission and re-ordering of handshake messages results in significant complexity and reliability problems. Additional reliability mechanisms for transporting DTLS handshake messages are required as they will ensure that handling of re-ordered messages needs to be done only once in a single place in the stack. The DICE working group may also look at alternative TLS transports in cooperation with the TLS WG.

The DTLS state machine should not be modified and key management (including for multicast security) and multi-cast session setup are out the scope for the initial work.

The DICE working group will work closely with the TLS, CoRE and LWIG working groups.