Extension for protecting (D)TLS handshakes against Denial of Service

Document Type Expired Internet-Draft (individual)
Authors Marco Tiloca  , Ludwig Seitz  , Maarten Hoeve  , Olaf Bergmann 
Last updated 2018-09-06 (latest revision 2018-03-05)
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


This document describes an extension for TLS and DTLS to protect the server from Denial of Service attacks against the handshake protocol, carried out by an on-path adversary. The extension includes a nonce and a Message Authentication Code (MAC) over that nonce, encoded as a Handshake Token that a Trust Anchor entity computes and provides to the client. The server registered at the Trust Anchor verifies the MAC to determine whether continuing or aborting the handshake.


Marco Tiloca (marco.tiloca@ri.se)
Ludwig Seitz (ludwig.seitz@ri.se)
Maarten Hoeve (maarten.hoeve@encs.eu)
Olaf Bergmann (bergmann@tzi.org)

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)