X-Git-Url: http://www.git.cypherpunks.ru/?a=blobdiff_plain;f=doc%2Ffeatures.rst;h=76d6830d3913f6872ae1a2f25608f5a9d1916515;hb=7af6ff46e2927030706fc4c0df0ddeadfa55dd79;hp=dcbd0ebcdc8b3ce6c9afdae23050a869411b0eef;hpb=93983afa262463982e07a617c2904df7fbfb47b3;p=pyderasn.git

diff --git a/doc/features.rst b/doc/features.rst
index dcbd0eb..76d6830 100644
--- a/doc/features.rst
+++ b/doc/features.rst
@@ -1,53 +1,86 @@
 Features
 ========
 
+* BER/CER/DER decoding, DER encoding
 * Basic ASN.1 data types (X.208): BOOLEAN, INTEGER, BIT STRING, OCTET
   STRING, NULL, OBJECT IDENTIFIER, ENUMERATED, all strings, UTCTime,
   GeneralizedTime, CHOICE, ANY, SEQUENCE (OF), SET (OF)
 * Size :ref:`constraints <bounds>` checking
 * Working with sequences as high level data objects with ability to
   (un)marshall them
-* Python 2.7/3.5 compatibility
+* Python 2.7/3.5/3.6 compatibility
+* Aimed to be complaint with `X.690-201508 <https://www.itu.int/rec/T-REC-X.690-201508-I/en>`__
 
-Why yet another library? `pyasn1 <https://github.com/etingof/pyasn1>`__
+Why yet another library? `pyasn1 <http://snmplabs.com/pyasn1/>`__
 had all of this a long time ago. PyDERASN resembles it in many ways. In
 practice it should be relatively easy to convert ``pyasn1``'s code to
-``pyderasn``'s one. But additionally it offers:
+``pyderasn``'s one.
+Also there is `asn1crypto <https://github.com/wbond/asn1crypto>`__.
 
 * Small, simple and trying to be reviewable code. Just a single file
-* Automatic decoding of :ref:`DEFINED BY <definedby>` fields
+  with `six <https://pypi.org/project/six/>`__ dependency
 * Ability to know :ref:`exact decoded <decoding>` objects offsets and
   lengths inside the binary
-* :ref:`Pretty printer <pprinting>` and command-line decoder, that could
-  conveniently replace utilities like either ``dumpasn1`` or
-  ``openssl asn1parse``
+* Automatic decoding of :ref:`DEFINED BY <definedby>` fields
+* Ability to know exact decoded field presence, emptiness: for example
+  ``SEQUENCE`` can lack ``OPTIONAL SEQUENCE OF`` field, but also can
+  have it with no elements inside
+* **Strict** DER-encoding checks. If whole input binary is parsed, then
+  it must be completely valid DER-encoded structure
+* Ability to allow BER-encoded data with knowing if any of specified
+  field has either DER or BER encoding (or possibly indefinite-length
+  encoding). For example
+  `CMS <https://en.wikipedia.org/wiki/Cryptographic_Message_Syntax>`__
+  structures allow BER encoding for the whole message, except for
+  ``SignedAttributes`` -- you can easily verify your CMS satisfies that
+  requirement
+* Extensive and comprehensive
+  `hypothesis <https://hypothesis.readthedocs.io/en/master/>`__
+  driven tests coverage. It also has been fuzzed with
+  `python-afl <http://jwilk.net/software/python-afl>`__
 * Some kind of strong typing: SEQUENCEs require the exact **type** of
-  settable values, even when they are inherited
-* However they do not require tags matching: IMPLICIT/EXPLICIT tags will
-  be set automatically in the given sequence
-* ``__slots__`` friendliness
-* Could be significantly faster. For example parsing of CACert.org's CRL
-  under Python 3.5.2:
+  settable values, even when they are inherited (assigning ``Integer``
+  to the field with the type ``CMSVersion(Integer)`` is not allowed)
+* However they do not require exact tags matching: IMPLICIT/EXPLICIT
+  tags will be set automatically in the given sequence (assigning of
+  ``CMSVersion()`` object to the field ``CMSVersion(expl=...)`` will
+  automatically set required tags)
+* Descriptive errors, like ``pyderasn.DecodeError: UTCTime
+  (tbsCertificate:validity:notAfter:utcTime) (at 328) invalid UTCTime format``
+* ``__slots__``, ``copy.copy()``, ``pickle``, `Cython <https://cython.org/>`__
+  friendliness
+* Could be significantly faster and have lower memory usage
+  For example parsing of CACert.org's CRL (8.48 MiB) on FreeBSD 12.0
+  amd64, Intel Core i5-6200U 2.3 GHz machine, Python 3.5.5/2.7.15:
 
-    :``python -m pyderasn revoke.crl``:
-     ~2 min (``pyderasn == 1.0``)
-    :``python -m pyderasn --schema path.to.CertificateList revoke.crl``:
-     ~38 sec (``pyderasn == 1.0``)
-    :``pyasn1.decode(asn1Spec=pyasn1.CertificateList())``:
-     ~22 min (``pyasn1 == 0.2.3``)
+  .. list-table::
+     :widths: 15 45 20 20
+     :header-rows: 1
 
-There are drawbacks:
-
-* No old Python versions support
-* No BER/CER support
-* PyDERASN does **not** have object recreation capable ``repr``-s::
-
-    pyderasn>>> repr(algo_id)
-    AlgorithmIdentifier SEQUENCE[OBJECT IDENTIFIER 1.3.14.3.2.26, [UNIV 5] ANY 0500 OPTIONAL]
+     * - Library
+       - Command
+       - Time, sec (Py3/Py2)
+       - Memory used, MiB (Py3/Py2)
+     * - pyasn1 0.4.5
+       - ``der_decode(data, asn1Spec=rfc5280.CertificateList())``
+       - 1257 / 1302
+       - 1327 / 2093
+     * - asn1crypto 0.24.0
+       - ``asn1crypto.crl.CertificateList.load(data).native``
+       - 29.3 / 43.8
+       - 983 / 1677
+     * - pyderasn 4.9
+       - ``CertificateList().decode(data)`` (CertificateList is
+         converted ``pyasn1`` scheme definition)
+       - 27.6 / 32.5
+       - 498 / 488
+* :ref:`Pretty printer <pprinting>` and
+  :ref:`command-line decoder <cmdline>`, that could
+  conveniently replace utilities like either ``dumpasn1`` or
+  ``openssl asn1parse``
 
-    pyasn1>>> repr(algo_id)
-    AlgorithmIdentifier().setComponents(ObjectIdentifier('1.3.14.3.2.26'), Any(hexValue='0500'))
+  .. figure:: pprinting.png
+     :alt: Pretty printing example output
 
-* Strings are not validated in any way, except just trying to be decoded
-  in ``ascii``, ``iso-8859-1``, ``utf-8/16/32`` correspondingly
-* No REAL, RELATIVE OID, EXTERNAL, INSTANCE OF, EMBEDDED PDV, CHARACTER STRING
+     An example of pretty printed X.509 certificate with automatically
+     parsed DEFINED BY fields.