The Datagram Transport Layer Security (DTLS) Protocol Version 1.3
draft-ietf-tls-dtls13-26
TLS E. Rescorla
Internet-Draft RTFM, Inc.
Obsoletes: 6347 (if approved) H. Tschofenig
Intended status: Standards Track Arm Limited
Expires: September 6, 2018 N. Modadugu
Google, Inc.
March 05, 2018
The Datagram Transport Layer Security (DTLS) Protocol Version 1.3
draft-ietf-tls-dtls13-26
Abstract
This document specifies Version 1.3 of the Datagram Transport Layer
Security (DTLS) protocol. DTLS 1.3 allows client/server applications
to communicate over the Internet in a way that is designed to prevent
eavesdropping, tampering, and message forgery.
The DTLS 1.3 protocol is intentionally based on the Transport Layer
Security (TLS) 1.3 protocol and provides equivalent security
guarantees. Datagram semantics of the underlying transport are
preserved by the DTLS protocol.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on September 6, 2018.
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document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
Rescorla, et al. Expires September 6, 2018 [Page 1]
Internet-Draft DTLS 1.3 March 2018
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions and Terminology . . . . . . . . . . . . . . . . . 4
3. DTLS Design Rationale and Overview . . . . . . . . . . . . . 5
3.1. Packet Loss . . . . . . . . . . . . . . . . . . . . . . . 6
3.1.1. Reordering . . . . . . . . . . . . . . . . . . . . . 7
3.1.2. Message Size . . . . . . . . . . . . . . . . . . . . 7
3.2. Replay Detection . . . . . . . . . . . . . . . . . . . . 7
4. The DTLS Record Layer . . . . . . . . . . . . . . . . . . . . 7
4.1. Sequence Number Handling . . . . . . . . . . . . . . . . 9
4.1.1. Determining the Header Format . . . . . . . . . . . . 10
4.1.2. Reconstructing the Sequence Number and Epoch . . . . 11
4.2. Transport Layer Mapping . . . . . . . . . . . . . . . . . 11
4.3. PMTU Issues . . . . . . . . . . . . . . . . . . . . . . . 12
4.4. Record Payload Protection . . . . . . . . . . . . . . . . 14
4.4.1. Anti-Replay . . . . . . . . . . . . . . . . . . . . . 14
4.4.2. Handling Invalid Records . . . . . . . . . . . . . . 14
5. The DTLS Handshake Protocol . . . . . . . . . . . . . . . . . 15
5.1. Denial-of-Service Countermeasures . . . . . . . . . . . . 16
5.2. DTLS Handshake Message Format . . . . . . . . . . . . . . 18
5.3. ClientHello Message . . . . . . . . . . . . . . . . . . . 20
5.4. Handshake Message Fragmentation and Reassembly . . . . . 21
5.5. DTLS Handshake Flights . . . . . . . . . . . . . . . . . 22
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