<https://golang.org/pkg/encoding/asn1/>`__ test suite (assuming that
it's DER encoded representation is already in ``raw`` variable)::
- >>> crt, tail = Certificate().decode(raw)
+ >>> crt = Certificate().decod(raw)
>>> crt
Certificate SEQUENCE[tbsCertificate: TBSCertificate SEQUENCE[
version: [0] EXPLICIT Version INTEGER v3 OPTIONAL;
serialNumber: CertificateSerialNumber INTEGER 61595;
signature: AlgorithmIdentifier SEQUENCE[OBJECT IDENTIFIER 1.2.840.113549.1.1.5...
-Pretty printing
----------------
-
-There is huge output. Let's pretty print it::
-
- >>> print(pprint(crt))
- 0 [1,3,1604] Certificate SEQUENCE
- 4 [1,3,1453] . tbsCertificate: TBSCertificate SEQUENCE
- 10-2 [1,1, 1] . . version: [0] EXPLICIT Version INTEGER v3 OPTIONAL
- 13 [1,1, 3] . . serialNumber: CertificateSerialNumber INTEGER 61595
- 18 [1,1, 13] . . signature: AlgorithmIdentifier SEQUENCE
- 20 [1,1, 9] . . . algorithm: OBJECT IDENTIFIER 1.2.840.113549.1.1.5
- 31 [0,0, 2] . . . parameters: [UNIV 5] ANY OPTIONAL
- . . . . 05:00
- 33 [0,0, 278] . . issuer: Name CHOICE rdnSequence
- 33 [1,3, 274] . . . rdnSequence: RDNSequence SEQUENCE OF
- 37 [1,1, 11] . . . . 0: RelativeDistinguishedName SET OF
- 39 [1,1, 9] . . . . . 0: AttributeTypeAndValue SEQUENCE
- 41 [1,1, 3] . . . . . . type: AttributeType OBJECT IDENTIFIER 2.5.4.6
- 46 [0,0, 4] . . . . . . value: [UNIV 19] AttributeValue ANY
- . . . . . . . 13:02:45:53
- [...]
- 1461 [1,1, 13] . signatureAlgorithm: AlgorithmIdentifier SEQUENCE
- 1463 [1,1, 9] . . algorithm: OBJECT IDENTIFIER 1.2.840.113549.1.1.5
- 1474 [0,0, 2] . . parameters: [UNIV 5] ANY OPTIONAL
- . . . 05:00
- 1476 [1,2, 129] . signatureValue: BIT STRING 1024 bits
- . . 68:EE:79:97:97:DD:3B:EF:16:6A:06:F2:14:9A:6E:CD
- . . 9E:12:F7:AA:83:10:BD:D1:7C:98:FA:C7:AE:D4:0E:2C
- [...]
-
- Trailing data: 0a
-
-Let's parse that output, human::
-
- 10-2 [1,1, 1] . . version: [0] EXPLICIT Version INTEGER v3 OPTIONAL
- ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
- 0 1 2 3 4 5 6 7 8 9 10 11
-
-::
-
- 20 [1,1, 9] . . . algorithm: OBJECT IDENTIFIER 1.2.840.113549.1.1.5
- ^ ^ ^ ^ ^ ^ ^ ^
- 0 2 3 4 5 6 9 10
-
-::
-
- 33 [0,0, 278] . . issuer: Name CHOICE rdnSequence
- ^ ^ ^ ^ ^ ^ ^ ^ ^
- 0 2 3 4 5 6 8 9 10
-
-::
+:ref:`Look here <pprint_example>` for better pretty printing.
- 52-2∞ B [1,1,1054]∞ . . . . eContent: [0] EXPLICIT BER OCTET STRING 1046 bytes
- ^ ^ ^ ^ ^
- 12 13 14 9 10
-
-:0:
- Offset of the object, where its DER/BER encoding begins.
- Pay attention that it does **not** include explicit tag.
-:1:
- If explicit tag exists, then this is its length (tag + encoded length).
-:2:
- Length of object's tag. For example CHOICE does not have its own tag,
- so it is zero.
-:3:
- Length of encoded length.
-:4:
- Length of encoded value.
-:5:
- Visual indentation to show the depth of object in the hierarchy.
-:6:
- Object's name inside SEQUENCE/CHOICE.
-:7:
- If either IMPLICIT or EXPLICIT tag is set, then it will be shown
- here. "IMPLICIT" is omitted.
-:8:
- Object's class name, if set. Omitted if it is just an ordinary simple
- value (like with ``algorithm`` in example above).
-:9:
- Object's ASN.1 type.
-:10:
- Object's value, if set. Can consist of multiple words (like OCTET/BIT
- STRINGs above). We see ``v3`` value in Version, because it is named.
- ``rdnSequence`` is the choice of CHOICE type.
-:11:
- Possible other flags like OPTIONAL and DEFAULT, if value equals to the
- default one, specified in the schema.
-:12:
- Shows does object contains any kind of BER encoded data (possibly
- Sequence holding BER-encoded underlying value).
-:13:
- Only applicable to BER encoded data. Indefinite length encoding mark.
-:14:
- Only applicable to BER encoded data. If object has BER-specific
- encoding, then ``BER`` will be shown. It does not depend on indefinite
- length encoding. ``EOC``, ``BOOLEAN``, ``BIT STRING``, ``OCTET STRING``
- (and its derivatives), ``SET``, ``SET OF`` could be BERed.
+.. _cmdline:
As command line utility
-----------------------
You can decode DER/BER files using command line abilities and get the
same picture as above by executing::
- % python -m pyderasn --schema tests.test_crts:Certificate path/to/file
+ $ python -m pyderasn --schema tests.test_crts:Certificate path/to/file
If there is no schema for you file, then you can try parsing it without,
but of course IMPLICIT tags will often make it impossible. But result is
good enough for the certificate above::
- % python -m pyderasn path/to/file
+ $ python -m pyderasn path/to/file
0 [1,3,1604] . >: SEQUENCE OF
4 [1,3,1453] . . >: SEQUENCE OF
8 [0,0, 5] . . . . >: [0] ANY
then you can pass it to pretty printer to see human readable OIDs::
- % python -m pyderasn --oids tests.test_crts:some_oids path/to/file
+ $ python -m pyderasn --oids tests.test_crts:some_oids path/to/file
[...]
37 [1,1, 11] . . . . . . >: SET OF
39 [1,1, 9] . . . . . . . . >: SEQUENCE OF
unique path inside the whole ASN.1 tree. You can print it out with
``--print-decode-path`` option::
- % python -m pyderasn --schema path.to:Certificate --print-decode-path path/to/file
+ $ python -m pyderasn --schema path.to:Certificate --print-decode-path path/to/file
0 [1,3,1604] Certificate SEQUENCE []
4 [1,3,1453] . tbsCertificate: TBSCertificate SEQUENCE [tbsCertificate]
10-2 [1,1, 1] . . version: [0] EXPLICIT Version INTEGER v3 OPTIONAL [tbsCertificate:version]
Now you can print only the specified tree, for example signature algorithm::
- % python -m pyderasn --schema path.to:Certificate --decode-path-only tbsCertificate:signature path/to/file
+ $ python -m pyderasn --schema path.to:Certificate --decode-path-only tbsCertificate:signature path/to/file
18 [1,1, 13] AlgorithmIdentifier SEQUENCE
20 [1,1, 9] . algorithm: OBJECT IDENTIFIER 1.2.840.113549.1.1.5
31 [0,0, 2] . parameters: [UNIV 5] ANY OPTIONAL
If you have bad DER/BER, then errors will show you where error occurred::
- % python -m pyderasn --schema tests.test_crts:Certificate path/to/bad/file
+ $ python -m pyderasn --schema tests.test_crts:Certificate path/to/bad/file
Traceback (most recent call last):
[...]
pyderasn.DecodeError: UTCTime (tbsCertificate:validity:notAfter:utcTime) (at 328) invalid UTCTime format
::
- % python -m pyderasn path/to/bad/file
+ $ python -m pyderasn path/to/bad/file
[...]
pyderasn.DecodeError: UTCTime (0:SequenceOf:4:SequenceOf:1:UTCTime) (at 328) invalid UTCTime format