]> Clarifications for Ed25519, Ed448, X25519, and X448 Algorithm Identifiers sn3rd
sean@sn3rd.com
SJD AB
simon@josefsson.org
Square Inc.
daniel@binaryparadox.net
SECOM CO., LTD.
tadahiko.ito.public@gmail.com
sec lamps PKIX X.509 keyUsage Elliptic Curve Cryptography This document updates RFC 8410 to clarify existing semantics, and specify missing semantics, for key usage bits when used in certificates that support the Ed25519, Ed448, X25519, and X448 Elliptic Curve Cryptography algorithms.
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 keyUsage 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 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 any of the following MUST NOT be present: If the keyUsage extension is present in an end-entity certificate that indicates id-Ed25519 or id-Ed448 in SubjectPublicKeyInfo, then the keyUsage extension MUST contain at least one of the following: and any of the following MUST NOT be present: If the keyUsage extension is present in a CRL issuer certificate that indicates id-Ed25519 or id-Ed448 in SubjectPublicKeyInfo, then the keyUsage extension MUST contain: and zero or more of the following: and any of the following MUST NOT be present: and if the CRL issuer is also a certification authority, then the keyUsage extension MUST also contain: 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 any of 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 Informative References Erratum ID 5696 RFC Errata RFC 8410
Acknowledgments We would like to thank , , and for their comments.