BDOC is a digital signature format created to replace the DDOC (DigiDoc) digital signature format specific to Estonia.
There are two technically different subformats of the BDOC digital signature format. They use different file extensions: .bdoc and .asice to make it easier for a standard user to distinguish between them.
The European Union countries, incl. Estonia, mainly use the .asice format and digital signatures added with the DigiDoc4 client are automatically given the .asice extension.
Signed files in .asice format
The .asice, i.e. BDOC-TS or ASiC-E LT, signature is a BDOC signature with a timestamp. Unlike in the case of the LT-TM format (digitally signed files with .bdoc extension), the long-term evidential value is ensured with a timestamp based on the RFC 3161 standard. ASiC-E LT signatures have the best international compatibility. DigiDoc4 automatically uses the .asice format when signing all new documents.
Signed files in .bdoc format
The .bdoc, i.e. BDOC-TS or ASiC-E LT-TM, signature is a BDOC signature with a timestamp. This means that the long-term evidential value of the digital signature is ensured by a time-mark based on the RFC 2560 standard. This has been the default signature format in Estonia since 2015. As this is an Estonia-based format, the .asice format is usually preferred.
BDOC2.1 – New Estonian digital signature standard format
The new version of the Estonian digital signature standard can be purchased from the Estonian Centre for Standardisation. Read more on how to purchase the digital signature standard and its revision history.
Main differences between DDOC and BDOC
A significant change from DDOC is that BDOC files are ZIP containers that include signed files, signatures and control information. As ZIP is a compressed format, BDOC files can be significantly smaller than DDOC files (which are XML text files). Additionally, the forwarding of BDOC files as ZIP files via e-mail is better supported (some mail servers filtered out DDOC attachments).
All DDOC files remained valid during the period of transitioning to BDOC format and the ID-software initially supported both formats. Today, .ddoc format is no longer used and all files are .bdoc format.