# About files

Learn which file types to expect and how to retrieve them.

# The unsigned files

First, here's an overview of the file types supported by our API.

Identity Provider (IDP) PDF Text Html XML
Norwegian BankID Yes Yes N/A Yes
Norwegian BankID on Mobile Yes* (1) Yes* (2) N/A N/A
Buypass Yes Yes N/A N/A
Swedish BankID Yes Yes N/A N/A
Danish NemID Yes* (3) Yes N/A Yes
  1. Supported with reference sign.
  2. Supported with reference sign on longer texts.
  3. Only a subset of the PDF specification is supported for signing. For further information, refer to the Implementation Guidelines (opens new window), section 5.4.2 PDF whitelisting. It is recommended that PDF documents used for signing comply with the PDF/A standard.

What is reference sign?

Norwegian BankID on Mobile only offers signing of short texts. As a workaround we sign the document checksum.

# Converting files

Our API supports conversion of the most common file types (docx, odt, txt, ..) to the pdf format in the API call if you don't want to do that yourself. For further information, refer to How to create a document.

# The signed files for a PKI signature

See the table below for available signed files on the document.

File Norwegian BankID Norwegian BankID mobile Swedish BankID Danish NemID
PDF native, standard_packaging, pades native*(1), standard_packaging, pades standard_packaging, pades standard_packaging, pades
Text native, standard_packaging native*(1), standard_packaging standard_packaging standard_packaging
XML native, standard_packaging native*(1), standard_packaging N/A standard_packaging

1.Only if there is a single signer on the document


In addition to the document files, you can download native and standard_packaging files from each of the signers.

# The native file

The file type we call native is actually the raw signature we retrieve from the ID provider, so each signer will have a native file you can download. On the document, however, only Norwegian BankID supports a merged native file for all the signers as a single file.

# The standard_packaging file

The standard_packaging file is a file of our own making. The file contains the raw signature(s), in addition to log statements explaining the signature process.

# The PAdES file

The end product of a digital signature process is a PAdES (PDF Advanced Electronic Signature). This is a standardised PDF format which contains key information about the signature, such as a timestamp and details about the eID method used to sign (i.e. BankID).

Signature data is incorporated directly within the signed PDF document, much like an ink signature becomes an integral part of a paper document, allowing the complete self-contained PDF file to be copied, stored, and distributed as a single electronic file. The document can be validated by a third party to ensure that the document has not been faked or tampered with. Our validation API can be used to validate signed documents.

A significant advantage of PAdES is that it is being deployed by means of widely available PDF software: it does not require development or customisation of specialised software. When opening a PAdES in, for instance, Acrobat Reader, a blue line will appear at the top of the document. This blue line indicates that the document integrity is intact and that the document has not been changed or tampered with after the time of signature.

# PAdES file size

The size of the PAdES document will be approximately 2-3 times larger than the original document if you have a single signer. For multiple signers it will further increase in size.

Last updated: 20/07/2023 12:11 UTC