Specification of post-quantum Matter operational certificate formats

Specify post-quantum operational certificate formats for Matter that support the public-key and signature sizes required by post-quantum algorithms and enable interoperable CASE handshakes.

Background

The message-size analysis constructs post-quantum certificates by modifying existing Matter certificate templates because Matter has not defined post-quantum operational certificate formats. The resulting encodings are explicitly treated as an assumption, so interoperability, exact encoding overhead, and compatibility with future Matter specifications remain unresolved. This issue is especially important because certificate size is a major determinant of whether a fully post-quantum CASE handshake can fit within Matter’s 1178-byte message limit.