Certificate Limitation Policy
draft-belyavskiy-certificate-limitation-policy-04

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Network Working Group
Internet-Draft                                                       TCI
Intended status: Experimental                         September 11, 2017
Expires: March 15, 2018

                     Certificate Limitation Policy
           draft-belyavskiy-certificate-limitation-policy-04

Abstract

   The document provides a specification of the application-level trust
   model.  Being provided at the application level, the limitations of
   trust can be distributed separately using cryptographically protected
   format instead of hardcoding the checks into the application itself.

Status of This Memo

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   This Internet-Draft will expire on March 15, 2018.

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Internet-Draft        Certificate Limitation Policy       September 2017

1.  Introduction

   Binary trust model standardized as a set of trusted anchors and CRLs/
   OCSP services does not cover all corner cases in the modern crypto
   world.  There is a need in more differentiated limitations.  Some of
   them are suggested [1] by Google when it limits the usage of
   Symantec's certificates.  The CRL profile does not fit the purpose of
   such limitations.  The CRLs are issued by the same CAs that are
   subject to be limited.

   Currently the set of CAs trusted by OS or browsers can be used for
   the validation purposes.  In case when a large enough CA becomes
   untrusted, it cannot be deleted from the storage of trusted CAs
   because it may cause error of validation of many certificates.  The
   measures usually taken in such cases usually include application-
   level limitation of certificates lifetimes, refusing to accept EV-
   certificates in other way than DV, requirements to use Certificate
   Transparency, etc.

   This document suggests a cryptographically signed format dubbed
   Certificate Limitation Profile (CLP) designed for description of such
   limitations.  This format can be used by applications that use
   system-wide set of trust anchors for validating purposes or by
   applications with own wide enough set of trusted anchors in case when
   the trust anchor for the entity found misbehaving cannot be revoked.

   Currently the only way to provide such limitations is hard coding
   them in application itself.  Using of CLPs does not allow to
   completely avoid hard coding but allows to hard code only the minimal
   set of rarely changing data:

      the fact that application uses CLP

      the certificate to verify the signature under the CLP file

      minimal date of the CLP to be used for the current version of
      application.

   It will be possible to move the checks for the limitations to the
   external cryptographical libraries, such as OpenSSL, instead of
   checking them at the application level.

2.  Certificate Limitations Profile

   A proposed syntax and overall structure of CLP is very similar to the
   one defined for CRLs [2].

                         Expires March 15, 2018                 [Page 2]
Internet-Draft        Certificate Limitation Policy       September 2017

      CertificateList  ::=  SEQUENCE  {
           tbsCertList          TBSCertList,
           signatureAlgorithm   AlgorithmIdentifier,
           signatureValue       BIT STRING  }

      TBSCertList  ::=  SEQUENCE  {
           version                 Version,
           signature               AlgorithmIdentifier,
           issuer                  Name,
           thisUpdate              Time,
           limitedCertificates     SEQUENCE OF SEQUENCE  {
                userCertificate         CertificateSerialNumber,