Simple Public Key Infrastructure S-Expressions
RFC 9804, “Simple Public Key Infrastructure S-Expressions”, is an Informational document published in June 2025 by R. Rivest, D. Eastlake 3rd. The canonical text is published by the RFC Editor.
Abstract
This memo specifies the data structure representation that was devised to support Simple Public Key Infrastructure (SPKI) certificates, as detailed in RFC 2692, with the intent that it be more widely applicable. It has been and is being used elsewhere. There are multiple implementations in a variety of programming languages. Uses of this representation are referred to in this document as "S-expressions". This memo makes precise the encodings of these SPKI S-expressions: It gives a "canonical form" for them, describes two "transport" representations, and also describes an "advanced" format for display to people.
What “Informational” means
Published for the general information of the community. It does not define an IETF standard and carries no standards-track status.
The canonical text of RFC 9804 is hosted at rfc-editor.org. Available in HTML,TXT,PDF,XML.
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