THPDFSignatureInputKind Type

Tells a signature provider whether the request input carries the raw message or a digest computed in advance

Declaration

THPDFSignatureInputKind= (
  sikMessage,
  sikDigest
  );

HPDFSignatureProvider

Value	Purpose
`sikMessage`	The request input holds the message bytes themselves; PureEdDSA providers such as Ed25519 and Ed448 insist on this and hash internally
`sikDigest`	The request input holds a digest that has already been computed; digest-based signers such as RSA and ECDSA insist on this

Providers turn down a request whose input kind does not match their algorithm with spsMalformed, so check the algorithm before filling in the request
With sikMessage there is no separate hashing step, which is precisely what PureEdDSA expects; any digest you pass would be signed as opaque data
Use sikDigest where the bytes to hash have already been consumed elsewhere, for example whilst the placeholder digest was being computed during signing