Clarifications for Elliptic Curve Cryptography Subject Public Key Information SECOM CO., LTD.
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LAMPS PKIX X.509 This document updates RFC 5480 to specify semantics for the keyEncipherment and dataEncipherment key usage bits when used in certificates that support Elliptic Curve Cryptography.
Status of This Memo This is an Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at .
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Table of Contents
  • .  Introduction
  • .  Terminology
  • .  Updates to Section 3
  • .  Security Considerations
  • .  IANA Considerations
  • .  Normative References
  • Authors' Addresses
Introduction specifies the syntax and semantics for the Subject Public Key Information field in certificates that support Elliptic Curve Cryptography. As part of these semantics, it defines what combinations are permissible for the values of the key usage extension . specifies 7 of the 9 values; it makes no mention of the keyEncipherment and dataEncipherment key usage bits. This document corrects this omission by updating to make it clear that neither keyEncipherment nor the dataEncipherment key usage bits are set for key agreement algorithms defined therein. The additions are to be made to the end of .
Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 when, and only when, they appear in all capitals, as shown here.
Updates to Section 3 If the keyUsage extension is present in a certificate that indicates id-ecPublicKey in SubjectPublicKeyInfo, then the following values MUST NOT be present:
  • keyEncipherment; and
  • dataEncipherment.
If the keyUsage extension is present in a certificate that indicates id-ecDH or id-ecMQV in SubjectPublicKeyInfo, then the following values also MUST NOT be present:
  • keyEncipherment; and
  • dataEncipherment.
Security Considerations This document introduces no new security considerations beyond those found in .
IANA Considerations This document has no IANA actions.
Normative References Key words for use in RFCs to Indicate Requirement Levels In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile This memo profiles the X.509 v3 certificate and X.509 v2 certificate revocation list (CRL) for use in the Internet. An overview of this approach and model is provided as an introduction. The X.509 v3 certificate format is described in detail, with additional information regarding the format and semantics of Internet name forms. Standard certificate extensions are described and two Internet-specific extensions are defined. A set of required certificate extensions is specified. The X.509 v2 CRL format is described in detail along with standard and Internet-specific extensions. An algorithm for X.509 certification path validation is described. An ASN.1 module and examples are provided in the appendices. [STANDARDS-TRACK] Elliptic Curve Cryptography Subject Public Key Information This document specifies the syntax and semantics for the Subject Public Key Information field in certificates that support Elliptic Curve Cryptography. This document updates Sections 2.3.5 and 5, and the ASN.1 module of "Algorithms and Identifiers for the Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile", RFC 3279. [STANDARDS-TRACK] Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings.
Authors' Addresses SECOM CO., LTD.
tadahiko.ito.public@gmail.com
sn3rd
sean@sn3rd.com