Time-Based Uni-Directional Attestation
draft-birkholz-rats-tuda-04

Document Type Active Internet-Draft (individual)
Authors Andreas Fuchs  , Henk Birkholz  , Ira McDonald  , Carsten Bormann 
Last updated 2021-01-13
Replaces draft-birkholz-i2nsf-tuda
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RATS Working Group                                              A. Fuchs
Internet-Draft                                               H. Birkholz
Intended status: Standards Track                          Fraunhofer SIT
Expires: July 17, 2021                                       I. McDonald
                                                          High North Inc
                                                              C. Bormann
                                                 Universitaet Bremen TZI
                                                        January 13, 2021

                 Time-Based Uni-Directional Attestation
                      draft-birkholz-rats-tuda-04

Abstract

   This document defines the method and bindings used to convey Evidence
   via Time-based Uni-Directional Attestation (TUDA) in Remote
   ATtestation procedureS (RATS).  TUDA does not require a challenge-
   response handshake and thereby does not rely on the conveyance of a
   nonce to prove freshness of remote attestation Evidence.  TUDA
   enables the creation of Secure Audit Logs that can constitute
   believable Evidence about both current and past operational states of
   an Attester.  In TUDA, RATS entities require access to a Handle
   Distributor to which a trustable and synchronized time-source is
   available.  The Handle Distributor takes on the role of a Time Stamp
   Authority (TSA) to distribute Handles incorporating Time Stamp Tokens
   (TST) to the RATS entities.  RATS require an Attesting Environment
   that generates believable Evidence.  While a TPM is used as the
   corresponding root of trust in this specification, any other type of
   root of trust can be used with TUDA.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on July 17, 2021.

Fuchs, et al.             Expires July 17, 2021                 [Page 1]
Internet-Draft                    TUDA                      January 2021

Copyright Notice

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   document authors.  All rights reserved.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Forward Authenticity  . . . . . . . . . . . . . . . . . .   4
     1.2.  TUDA Objectives . . . . . . . . . . . . . . . . . . . . .   5
     1.3.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   5
   2.  Remote Attestation Principles . . . . . . . . . . . . . . . .   6
     2.1.  Authenticity of Evidence  . . . . . . . . . . . . . . . .   6
     2.2.  Generating Evidence about Software Component Integrity  .   7
     2.3.  Measurements and Digests Generated by an Attester . . . .   7
     2.4.  Attesting Environments and Roots of Trust . . . . . . . .   8
     2.5.  Indeterministic Measurements  . . . . . . . . . . . . . .   9
   3.  TUDA Principles and Requirements  . . . . . . . . . . . . . .  10
     3.1.  Attesting Environment Requirements  . . . . . . . . . . .  11
     3.2.  Handle Distributor Requirements: Time Stamp Authority . .  11
   4.  Information Elements and Conveyance . . . . . . . . . . . . .  11
   5.  TUDA Core Concept . . . . . . . . . . . . . . . . . . . . . .  12
     5.1.  TPM Specific Terms  . . . . . . . . . . . . . . . . . . .  13
     5.2.  Certificates  . . . . . . . . . . . . . . . . . . . . . .  13
   6.  The TUDA Protocol Family  . . . . . . . . . . . . . . . . . .  14
     6.1.  TUDA Information Elements Update Cycles . . . . . . . . .  15
   7.  Sync Base Protocol  . . . . . . . . . . . . . . . . . . . . .  18
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  18
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  18
   10. Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  19
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  19
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