Time-Based Uni-Directional Attestation
draft-birkholz-rats-tuda-04
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
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on July 17, 2021.
Fuchs, et al. Expires July 17, 2021 [Page 1]
Internet-Draft TUDA January 2021
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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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