PAdES, XAdES and CAdES are the three main electronic signature formats under eIDAS, one each for PDF, XML and any binary file. The format is separate from the legal level (simple, advanced, or qualified). Tindom validates PAdES, XAdES, CAdES, and JAdES signed documents.
A signature’s eIDAS level (SES, AdES, or QES) describes how strong its legal standing is. Its format describes how it’s technically packaged inside, or alongside, the document. ETSI, the European standards body, defines the main formats; each is built around a different underlying document type.
PAdES (PDF Advanced Electronic Signatures, ETSI EN 319 142) embeds the signature directly inside the PDF file itself, using PDF’s native signature dictionary. It’s the format almost everyone encounters day to day, since it’s the one built into Adobe Acrobat and most e-signature platforms when the underlying document is a PDF. A single PDF can carry multiple PAdES signatures, useful for multi-party contracts.
XAdES (XML Advanced Electronic Signatures, ETSI EN 319 132) signs XML documents or fragments. It’s common in structured data exchange between systems rather than human-facing documents: government-to-government messaging, electronic invoicing formats, and API-based workflows where the payload is XML rather than a rendered document.
CAdES (CMS Advanced Electronic Signatures, ETSI EN 319 122) is built on CMS (Cryptographic Message Syntax), the same underlying structure as PKCS#7. Unlike PAdES and XAdES, it isn’t tied to a specific document format: it can sign any binary file, often as a separate detached signature file (commonly with a .p7s extension) that travels alongside the original, unmodified file rather than being embedded inside it.
JAdES (JSON Advanced Electronic Signatures) is a newer addition, built for JSON payloads rather than XML or binary files. As more government and financial infrastructure moves to JSON-based APIs, JAdES is the format built to keep pace. Tindom validates JAdES-signed documents alongside the other three.
A validator needs to know which format it’s looking at to check the signature correctly, since the cryptographic structure differs between PAdES, XAdES, CAdES, and JAdES. Tindom’s validator checks all four — whichever format the signing platform used — against every trust list it carries: the EU trusted lists, third-country lists recognised under eIDAS, the Swiss and UK trusted lists, and the Adobe Approved Trust List.