HPDFBuildHeadlessTimestampRequestForImprint
function HPDFBuildHeadlessTimestampRequestForImprint(const MessageImprint: SysUtils.TBytes;
Digest: THPDFHeadlessTimestampDigest; const Options: THPDFHeadlessTimestampOptions): SysUtils.TBytes;
Builds a bounded DER TimeStampReq from the exact supplied SHA256, SHA384 or SHA512 imprint, a fresh 128-bit cryptographic nonce and certReq enabled
The imprint length must match Digest, and the request honours Options.MaxSignatureBytes and CancellationToken
Retain the original request and pass it to HPDFVerifyHeadlessTimestampResponseForImprint to authenticate the nonce, imprint and digest selection
See Native RFC3161 timestamps for transport and trust configuration details