Home / The record / EdDSA, the new clause

The signed message is the message followed by the appendix, and the appendix is the witness, the second part and the optional text. The order is fixed: the message first, then the signature structure. A protocol that puts the appendix first is carrying the same values in a different container.

What it asks

Define the signed message layout in the interface specification and test it against a second implementation. Where the protocol frames the signature separately, record how the appendix is reconstructed before verification, because a reconstruction step is where the bytes drift.

What the amendment does

Inserts 6.13.4.8. So this is new text rather than a change to wording.

Who it binds

The protocol owner and the integration test owner.

Evidence an auditor samples

• The signed message layout, with the order of the parts (interface specification)
• The interoperation test with a second implementation (integration report)
• The reconstruction code and its test (source repository)

The test you can run

Verify a signed message produced by a second implementation without changing the bytes. A failure means the layout or the reconstruction is wrong.

Common failures

• The signature is base64 encoded and the encoding is not canonical.
• The appendix is rebuilt from separate fields and one field is defaulted.

How to close it

Interoperation is the only test that proves a layout. Run it against a second implementation before the release, and keep the fixture so that a library upgrade is checked against the same bytes. Start with the signed message layout, with the order of the parts and let the row close when it exists with a date and a named holder.

Where it sits against the base standard

The base standard does not carry this text. The amendment adds it, so an estate working from the 2018 edition alone will not find it. The citation has to name the amendment, and the record for 6.13.4.8 is the only place a reader can see it.