.. include:: ../abbreviations.txt

.. _asn1_json_conversion_rules_label:

|ASN.1| and |JSON| conversion rules
===================================

Conversion of ASN.1 primitive types into JSON are defined here. Main rules of *ITU-T X.697* specifications are followed.

Unsupported ASN.1 structures
----------------------------

Some ASN.1 structures **are not supported** for JSON conversion:

- ``REAL``
- ``ENUMERATED``

These types are not used by ICAO and eIDAS.


Differences with *ITU-T X.697* specifications
---------------------------------------------

ASN.1 ``ANY``
'''''''''''''

An *ASN.1 ANY* element is encoded as a **JSON string** in hexadecimal format (containing only ``0123456789ABCDEF``
characters). Returned string will contain DER ``Tag``, ``Length`` and ``Value``.


ASN1.1 named ``BIT STRING``
'''''''''''''''''''''''''''

If applicable, an **ASN.1 named BIT STRING** element is encoded as a **JSON object**, and:

- for each named ``BIT``, there is a *JSON key* with same name
- corresponding *JSON value* is ``true`` or ``false``, depending on corresponding ``BIT`` value