What is structured data?
Structured data is information organized according to a clearly defined scheme. This means that individual data elements are located in the intended places - for example, in specific fields or tags - allowing computers to automatically locate and interpret them without guessing at the context.
Examples of structured data
- XML files, such as e-invoice KSeF. The Ministry of Finance clearly states that „PDF, JPG ≠ e-Invoice, e-Invoice = XML.” A structured invoice is an invoice issued via KSeF along with the identification number assigned to this invoice in the system. The definition of a structured invoice was introduced for the purposes of the VAT Act.
- Electronic forms, where data is entered into specific fields (e.g., first name, last name, address).
- Table files (CSV, XLS/XLSX), where the information is arranged in rows and columns.
Due to its structure, such data are ideal for automatic processing. Computer systems easily import them into databases, check their correctness and use the information, for example, to generate reports or statements. A typical example is official forms or e-invoices, which can be mass-processed by government systems.
Unstructured data - what is it?
Unstructured data has no set pattern. They are simply texts, images or scans that are primarily intended to be read by humans. A computer cannot automatically extract detailed information from them because they lack metadata that defines the structure of the content.
Examples of unstructured data
- PDF documents, such as scans of letters or traditional contracts.
- DOCX or ODT text files, where the content is continuous and there are no separate information fields.
- Images or scans saved as JPG, PNG or PDF containing only graphics.
These documents are easy for humans to read, but require additional processing to extract usable data for computers.
How to choose the format of an electronic signature?
The distinction between structured and unstructured data is important when choosing an electronic signature format.
XAdES signature - for structured data
XAdES (XML Advanced Electronic Signature) is the optimal solution for XML documents, such as e-invoices, official forms (e.g. tax returns or applications to the Social Security Administration). This signature does not interfere with the structure of the document, thus preserving the integrity of the data. It can be saved inside an XML file or separately (as an external .xades or .xml file).
XAdES It allows a signed document to be automatically imported into a computer system, which simplifies and speeds up its further processing.
PAdES and CAdES signature - for unstructured data
- PAdES (PDF Advanced Electronic Signature) is ideal for PDF documents. The signature is integrated directly in the PDF file, so that the recipient receives one convenient document for verification. In addition, it is possible to graphically visualize the signature, which improves the readability and intuitiveness of the documents.
- CAdES (CMS Advanced Electronic Signature) can be used to sign virtually any file (Word, image, ZIP). Creates a separate signature file (usually .p7s), which attaches to the original document. It is particularly useful where you can't or don't want to convert the document to PDF. Keep in mind, this format is the oldest signature format, which originated from the classic cryptographic signature technology used for many years. You can read more about its limitations here (Internal versus external signature - differences, formats and applications (Part 2)
In practice ...
...WHY CHOOSE?
- Structured data (e.g., XML) are best signed with the format of the XAdES.
- Unstructured data (e.g. PDF, DOCX, scans) - format PAdES (for PDF) or CAdES (for other types of files).
Choosing the right electronic signature format for the type of data ensures the convenience, integrity of the document and efficiency of its further use by both humans and computer systems.
However, regardless of the method chosen, both types of signatures (SimplySign i Certum Mini) guarantee the same The level of security and legal validity implied by a qualified certificate.
With this knowledge, we can consciously choose the format and type of signature best suited to a given situation, ensuring both convenience and compliance.
Qualified signatures SimplySign and Certum Mini
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