Signature Formatting Provider

The Signature Formatting Provider is a connector interface responsible for assembling the data structures involved in a signing operation — building the exact bytes that Core must sign, and reconstituting the finished signed object once the signature is available. It holds no keys and performs no cryptographic signing itself; that stays with Core.

Overview

A connector implementing this interface is referenced by a Signing Profile as its Signature Formatting Connector. Core calls it around the cryptographic operation: once to prepare what must be signed, and once to assemble the signed result. The concrete structures produced depend on the implementation and the signing workflow.

How it works

Core calls a Signature Formatting Provider at two points in a signing operation:

1. formatDtbs — given the values Core has gathered for the operation, build the data to be signed (DTBS) and return the byte sequence that must be signed.
2. formatSigningResponse — after Core has signed the DTBS with the profile's managed key, assemble the signature and the formatted structures into the finished signed object.

Each call is independent — the connector receives everything it needs as request input and returns the result of that single step, with nothing carried over from the other call.

Attributes

An implementation may expose configurable attributes that control optional content in the formatted output. Attributes are set when configuring the connector on the Signing Profile and validated through the connector's Attributes interface; an unrecognized attribute name is rejected. The specific attributes depend on the implementation.

Implementations

Connector	Workflow	Output
Timestamp Formatting Connector	Timestamping	RFC 3161 timestamp tokens

Specification

A Signature Formatting Provider implements the Common Interfaces in addition to the two formatting operations above.