]> sn3rd

sean@sn3rd.com

SJD AB

simon@josefsson.org

Square Inc.

daniel@binaryparadox.net

SECOM CO., LTD.

tadahiko.ito.public@gmail.com

Security LAMPS Internet-Draft This document updates RFC 8410 to clarify existing and specify missing semantics for key usage bits when used in certificates that support the Ed25519, Ed448, X25519, and X448 Elliptic Curve Cryptography algorithms. About This Document Status information for this document may be found at . Source for this draft and an issue tracker can be found at .

Introduction specifies the syntax and semantics for the Subject Public Key Information field in certificates that support Ed25519, Ed448, X25519, and X448 Elliptic Curve Cryptography (ECC) algorithms. As part of these semantics, it defines what combinations are permissible for the values of the key usage extension . did not define what values are not permissible nor did it refer to keyEncipherment or dataEncipherment. has also been submitted to clarify that keyCertSign is always set in certification authority certificates. To address these changes, this document replaces Section 5 of with .

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.

New Section 5 for RFC 8410 The intended application for the key is indicated in the keyUsage certificate extension. If the keyUsage extension is present in a certificate that indicates id-X25519 or id-X448 in SubjectPublicKeyInfo, then the following MUST be present: one of the following MAY also be present: and the following MUST NOT be present: If the keyUsage extension is present in an end-entity or CRL issuer certificate that indicates id-Ed25519 or id-Ed448 in SubjectPublicKeyInfo, then the keyUsage extension MUST contain at least one of the following: and the following MUST NOT be present: If the keyUsage extension is present in a certification authority certificate that indicates id-Ed25519 or id-Ed448 in SubjectPublicKeyInfo, then the keyUsage extension MUST contain: and zero or more of the following: and the following MUST NOT be present:

Security Considerations This document introduces no new security considerations beyond those found in .

IANA Considerations This document has no IANA actions.

References Normative References This document specifies algorithm identifiers and ASN.1 encoding formats for elliptic curve constructs using the curve25519 and curve448 curves. The signature algorithms covered are Ed25519 and Ed448. The key agreement algorithms covered are X25519 and X448. The encoding for public key, private key, and Edwards-curve Digital Signature Algorithm (EdDSA) structures is provided. 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] 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. 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. Informative References

Acknowledgments We would like to thank Russ Housley, Mike Jenkins, and Corey Bonnell for the comments.