Glossary
The vocabulary, defined.
The standards vocabulary behind NextPDF, in plain English. Each entry names the standard it comes from so you can read the source.
- PDF 2.0ISO 32000-2
- The current PDF standard. It defines the modern PDF object model that NextPDF generates to natively — tagged structure, signature containers, archival profiles, and proper colour management — rather than shimming features onto a 1.x-era engine.
- PDF/UA-2ISO 14289-2
- The accessibility profile: a tagged logical structure (headings, reading order, figure alternative text, document language) so assistive technology can navigate a document’s meaning, not just its pixels.
- PDF/A-3ISO 19005-3
- An archival profile that permits embedded files. Hybrid e-invoices (ZUGFeRD / Factur-X) use it so the structured XML can live inside the human-readable PDF.
- PDF/A-4ISO 19005-4
- The newer archival profile for long-term preservation, built on PDF 2.0. NextPDF Enterprise targets it for standalone archival output.
- PAdESETSI EN 319 142-1
- PDF Advanced Electronic Signatures — the ETSI profiles that define how a standards-based signature is embedded in a PDF, across the baseline levels B-B, B-T, B-LT, and B-LTA.
- PAdES B-B (Baseline)ETSI EN 319 142-1
- The baseline level: a CMS SignedData container, embedded in the document via a /ByteRange, that binds the document to the signer. A Core capability.
- PAdES B-T (Timestamped)RFC 3161
- Adds an RFC 3161 trusted timestamp over the signature, attesting when it was signed by an independent time authority. A Pro capability.
- PAdES B-LT (Long-term)ETSI EN 319 142-1
- Embeds the validation material — the DSS, with certificates and revocation data — so the signature still verifies after the signing certificate expires or its revocation service goes offline. An Enterprise capability.
- PAdES B-LTA (Long-term archival)ETSI EN 319 142-1
- Adds renewable archival document timestamps over the validation material, so the signature keeps verifying across decades as algorithms age. An Enterprise capability.
- CMS SignedDataRFC 5652
- The Cryptographic Message Syntax structure that carries a digital signature and the signer’s certificate — the cryptographic core embedded inside a PAdES-signed PDF.
- ByteRangeISO 32000-2
- The PDF entry that records which bytes of the file a signature covers — typically the whole document around the hole that holds the signature itself — so a verifier can confirm nothing changed after signing.
- DSS (Document Security Store)ISO 32000-2
- A PDF structure that embeds the certificates and revocation data needed to validate a signature long after signing. It is what makes the long-term levels (B-LT / B-LTA) self-contained.
- RFC 3161 timestampRFC 3161
- A trusted timestamp from an independent Time-Stamping Authority, proving a signature existed at a point in time. NextPDF Pro adds it for the B-T level.
- EN 16931EN 16931-1
- The European semantic data model for the core of an electronic invoice. NextPDF Enterprise produces output that targets this model inside hybrid PDF invoices.
- ZUGFeRD / Factur-XEN 16931 · PDF/A-3
- The German (ZUGFeRD) and French (Factur-X) hybrid e-invoice formats: a human-readable PDF carrying an embedded EN 16931 XML payload, so one file is both readable by a person and ingestible by a tax system.
- ICC v4 colourISO 15076-1
- Version 4 ICC colour profiles for colour-managed output, so colours render predictably across devices — part of producing archival-grade documents.
- MCP (Model Context Protocol)
- A protocol for exposing tools to AI systems. NextPDF Connect speaks it (alongside REST and gRPC) so an agent can create, analyse, sign, and inspect PDFs through a typed, deterministic contract.
- HSM / PKCS#11
- A Hardware Security Module and the PKCS#11 interface to it: the private signing key stays inside the dedicated hardware module and the application only ever sees a signature, never the key. An Enterprise signing option.