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Versions: 00 01 02 03 04 RFC 4059

Internet Engineering Task Force                           D. Linsenbardt
Internet-Draft                                                S. Pontius
December 2002                                                A. Sturgeon
Expires: June 2003                                                 SPYRUS

                     Warranty Certificate Extension

Status of this Memo

  This document is an Internet-Draft and is in full conformance with all
  provisions of Section 10 of RFC2026.

  Internet-Drafts are working documents of the Internet Engineering Task
  Force (IETF), its areas, and its working groups.  Note that other
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  This document describes a certificate extension to explicitly state
  the warranty offered by a Certificate Authority (CA) for the
  certificate containing the extension.

Conventions Used In This Document

  The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
  document are to be interpreted as described in [RFC2119].

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1. Introduction

  The warranty certificate extension identifies the warranty policy
  associated with a X.509 public key certificate [X.509-97, PROFILE].
  Often the Certificate Authority (CA) will obtain an insurance policy
  to ensure coverage of the warranty.

  The certificate warranty provides an extended monetary coverage for
  the end entities.  The certificate warranty primarily concerns the use,
  storage, and reliance on a certificate by a subscriber, a relying party,
  and the CA.  It is common for a CA to establish reliance limits on the
  use of a certificate.  It is not uncommon for a CA to attempt through
  contractual means to exclude its liability entirely.  However, this
  has the effect of undermining the confidence that commerce requires to
  gainfully use certificates.

  Alternatively a CA may provide extended coverage for the use of the
  certificate.  Usually, the subscriber pays for the extended warranty
  coverage.  In turn, subscribers are covered by an appropriately drafted
  insurance policy.  The certificate warranty is backed by an insurance
  policy issued by a licensed insurance company, which results in a financial
  backing that is far greater than that of the CA.  This extra financial
  backing provides a further element of confidence necessary to encourage the
  use of certificates in commerce.

  A relying party that has a warranty from a CA may obtain compensation from a
  CA depending on the conditions for such compensation expressed in either the CA's
  Certificate Policy or the CA's insurance policy, or both.  Evidence of an extended     warranty, provided through the certificate extension, will give the relying party
  additional confidence that compensation is possible, and will therefore further
  enhance trust in the process.  Risk for a non-subscriber relying party may be
  reduced by the presence of a warranty extension with an explicit warranty stated.
  The warranty extension allows this aspect of risk management to be automated.

  When a certificate contains a warranty certificate extension, the extension MUST be   non-critical, and it MUST contain either a NULL to indicate that no warranty is
  provided or base warranty data to indicate that a warranty is provided.  The
  extension MAY contain optional qualifiers.

2. Warranty Extension Format

  Like all X.509 certificate extensions, the warranty certificate
  extension is defined using ASN.1 [X.208-88, X.209-88].

  The non-critical warranty extension is identified by

     id-pe-warrantyData OBJECT IDENTIFIER  ::=  { id-pe <<TBD>> }

  A non-null warranty always includes a base warranty.  The warranty
  information includes the period during which the warranty applies, a
  warranty value, and a warranty type.  The warranty type tells the
  warranty limit against claims.  The extension definition
  supports two alternatives: aggregated and per-transaction.  With
  aggregation, claims are fulfilled until a ceiling value is reached.
  After that, no further claims are fulfilled.  With per-transaction, a
  ceiling value is imposed on each claim, but each transaction is

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  considered independently.

  The warranty extension permits inclusion of two optional warranty
  qualifiers. The first qualifier provides extended warranty information.
  The second qualifier provides a pointer to the warranty terms and

  When present, the extended warranty information provides information
  about coverage beyond the scope of the base warranty.  Like the base
  warranty information, the extended warranty information includes the
  period during which the warranty applies, a warranty value, and a
  warranty type.

  When present, the terms and conditions pointer provides a reference to
  a document containing the terms and conditions associated with the
  warranty.  The document may be a Certificate Policy that contains this
  information, or it may be a document specifically about the warranty.
  It may also be a Relying Party Agreement.  The pointer is always a
  uniform resource locator (URL). The URL MUST be a non-relative URL,
  and it MUST follow the URL syntax and encoding rules specified in
  RFC 1738 [URL].

2.1. Warranty Extension Syntax

  The syntax for the warranty extension is:

     Warranty  ::=  CHOICE  {
       none                 NULL,            -- No warranty provided
       wData                WarrantyData  }  -- Explicit warranty

     WarrantyData  ::=  SEQUENCE  {
       base                 WarrantyInfo,
       extended             WarrantyInfo OPTIONAL,
       tcURL                TermsAndConditionsURL OPTIONAL  }

     WarrantyInfo  ::=  SEQUENCE  {
       validity             WarrantyValidityPeriod,
       amount               CurrencyAmount,
       wType                WarrantyType  }

     WarrantyValidityPeriod  ::=  CHOICE  {
       sameAsCertificate    NULL,
       explicitPeriod       ValidityPeriod  }

     ValidityPeriod  ::=  SEQUENCE  {
       notBefore            GeneralizedTime,
       notAfter             GeneralizedTime  }

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     -- CurrencyAmount specifies the currency and a monetary value.
     -- Currency codes are defined in ISO 4217.  The monetary value
     -- is: amount / (10 ** amtExp10), and the exponent MUST be the
     -- minor unit of currency specified in ISO 4217.

     CurrencyAmount  ::=  SEQUENCE  {
       currency             INTEGER (1..999),
       amount               INTEGER (0..MAX),
       amtExp10             INTEGER (0..MAX)  }

     WarrantyType  ::=  INTEGER  {
       aggregated           (0),
       perTransaction       (1)  }

     TermsAndConditionsURL  ::=  IA5String

2.2. Warranty Extension Semantics

  Warranty is a CHOICE; it is represented either by NULL or
  WarrantyData.  If the CA selects NULL, then the CA is explicitly
  stating that no warranty is provided.  If the CA selects WarrantyData,
  then the CA is explicitly stating that a warranty is provided, and the
  fields within the WarrantyData type MUST provide details about the
  warranty that is provided.

  WarrantyData MUST contain information about the base warranty.
  WarrantyData MAY contain information about an extended warranty.  Both
  base warranty and extended warranty information is provided using the
  WarrantyInfo type.  WarrantyData MAY contain a URL that points to the
  terms and conditions of the warranty.  The URL is provided using the
  TermsAndConditionsURL type, which is an IA5 string.

  WarrantyInfo MUST contain the warranty validity period, the currency
  amount of the warranty, and the type of warranty.  The warranty
  validity period is provided using the WarrantyValidityPeriod type.
  The currency amount of the warranty is provided using the
  CurrencyAmount type.  The type of warranty is provided using the
  WarrantyType type.

  WarrantyValidityPeriod is a CHOICE; it is represented either by NULL
  or ValidityPeriod.  If the CA selects NULL, then the validity period
  of the warranty MUST be exactly the same as the validity period of the
  certificate.  If the CA selects ValidityPeriod, then the CA is
  explicitly stating a warranty validity period that is different than
  the validity period of the certificate.  If the warranty validity
  period and the certificate validity period are the same, then the CA
  MUST select the NULL choice.  The validity periods are expected to be
  the same in the vast majority of the cases.

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  ValidityPeriod is a SEQUENCE of two GeneralizedTime values.  The first
  (notBefore) GeneralizedTime value MUST indicate the date and time that
  the warranty become valid, and the second (notAfter) GeneralizedTime
  value MUST indicate the date and time that the warranty expires.

  CurrencyAmount is a SEQUENCE if three integers.  Together the integers
  specify the currency and a monetary value.  The first integer
  (currency) MUST indicate the currency using one of the currency codes
  defined in ISO 4217.  The second integer (amount) MUST indicate the
  value of the warranty.  The third integer (amtExp10) MUST indicate the
  correct placement of the decimal point in the monetary value, and it
  MUST be the minor unit of currency specified in ISO 4217.  For example
  $48,525.50 (in US dollars) is represented as:
     currency =      840
     amount   =  4852550
     amtExp10 =        2

  WarrantyType is an integer.  A value of zero indicates that claims
  against the warranty will be aggregated, and once the value of
  fulfilled claims reaches the warranty currency amount, then no further
  claim will be fulfilled.  A value of one indicates that each claim is
  handled independently, but no individual claim can exceed the warranty
  currency amount.  The CA MUST select either zero or one for this
  integer value.

3. Security Considerations

  The procedures and practices employed by the CA MUST ensure that the
  correct values for the warranty are inserted in each certificate that is
  issued.  Relying parties and users may accept or reject a particular
  certificate for an intended use based on the information provided in
  warranty extension.  Incorrect representation of the actual warranty
  may result in otherwise avoidable warranty claims for the CA.

4. References

  ISO 4217  ISO. Codes for the Representation of Currencies and
            Funds," ISO 4217. 1995.

  PROFILE   Housley, R., Ford, W., Polk, W. and D. Solo, "Internet
            X.509 Public Key Infrastructure: Certificate and CRL
            Profile", RFC 3280, May 2002.

  URL       Berners-Lee, T., Masinter, L., and M. McCahill. "Uniform
            Resource Locators (URL)", RFC 1738, December 1994.

  X.208-88  CCITT.  Recommendation X.208: Specification of Abstract
            Syntax Notation One (ASN.1).  1988.

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  X.209-88  CCITT.  Recommendation X.209: Specification of Basic
            Encoding Rules for Abstract Syntax Notation One (ASN.1).

  X.509-97  ITU-T.  Recommendation X.509: The Directory -
            Authentication Framework.  1997.

This Internet-Draft was developed with the expertise and support of Russ Housley,
RSA Laboratories, and Dr. Adrian McCullagh, Freehills Australia.

Author's Address

  Duane Linsenbardt
  Sue Pontius
  2355 Oakland Road
  Suite 1
  San Jose CA 95131

  Alice Sturgeon
  Suite 1502, 222 Queen St.,
  Ottawa ON K0A 2T0

  Person & email address to contact for further information:
  Alice Sturgeon <asturgeon@spyrus.com>

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