What is MIME type "application/x-bdoc"?

A MIME type is a string that tells browsers and other tools how to handle a particular kind of file.

application/x-bdoc is used for container files that store digitally signed documents. It bundles the original document with its cryptographic signature and related metadata.

This format increases trust by ensuring the document’s integrity and authenticity. It is crucial in legal and secure communications where proof of origin and content integrity matter.

Files using this MIME type include containers such as BDOC and ASICE.

Digital signatures: They wrap the document with a signature to verify the issuer.
Data integrity: They protect against unauthorized modifications.
Secure document transmission between trusted parties.
Compliance with electronic legal signing standards.

The container design supports both verifying the signer’s credentials and confirming that the document has not been altered. For further technical details, visit ETSI or check file information on Filext.

Associated file extensions

.asice, .bdoc

Usage Examples

HTTP Header

When serving content with this MIME type, set the Content-Type header:


    Content-Type: application/x-bdoc

HTML

In HTML, you can specify the MIME type in various elements:


    <a href="file.dat" type="application/x-bdoc">Download file</a>

Server-side (Node.js)

Setting the Content-Type header in Node.js:


    const http = require('http');    
    
    http.createServer((req, res) => {    
      res.setHeader('Content-Type', 'application/x-bdoc');    
      res.end('Content here');    
    }).listen(3000);

Associated file extensions

.asice, .bdoc

FAQs

How do I open a file with the application/x-bdoc MIME type?

You need specialized digital signature software, such as the DigiDoc client or other eIDAS compliant tools, to properly view and verify these files. Standard text editors cannot interpret the binary structure of the container; learn more about the extensions at bdoc or asice.

How do I configure Apache to serve .bdoc and .asice files correctly?

To ensure browsers handle these signed containers correctly, add the AddType directive to your .htaccess or server configuration file. Use the line: AddType application/x-bdoc .bdoc .asice.

What is the correct Nginx configuration for application/x-bdoc?

In your Nginx mime.types file, you should map the MIME type to the relevant extensions. Add the line application/x-bdoc bdoc asice; and reload the server to apply the changes.

Why does my browser download the file instead of displaying it?

Web browsers like Chrome, Firefox, and Edge do not have native support for rendering digital signature containers. Therefore, the browser defaults to downloading the file so it can be handled by a desktop application capable of verifying the cryptographic signature.

Are .bdoc and .asice files actually ZIP archives?

Yes, modern BDOC and ASICE formats are often based on the ZIP standard. You can technically rename the file extension to .zip to extract the inner document, but doing so invalidates the digital signature and breaks the chain of trust.

Is application/x-bdoc the only MIME type used for these files?

While application/x-bdoc is common for legacy reasons and specific regional software (like Estonian ID software), the standard ASiC-E format may also use application/vnd.etsi.asic-e+zip. Always check the specific requirements of the client software consuming the documents.

General FAQ

What is a MIME type?

A MIME (Multipurpose Internet Mail Extensions) type is a standard that indicates the nature and format of a document, file, or assortment of bytes. MIME types are defined and standardized in IETF's RFC 6838.

MIME types are important because they help browsers and servers understand how to process a file. When a browser receives a file from a server, it uses the MIME type to determine how to display or handle the content, whether it's an image to display, a PDF to open in a viewer, or a video to play.

MIME types consist of a type and a subtype, separated by a slash (e.g., text/html, image/jpeg, application/pdf). Some MIME types also include optional parameters.

How do I find the MIME type for a file?

You can check the file extension or use a file identification tool such as file --mime-type on the command line. Many programming languages also provide libraries to detect MIME types.

Why are multiple MIME types listed for one extension?

Different applications and historical conventions may use alternative MIME identifiers for the same kind of file. Showing them all helps ensure compatibility across systems.