Package Crypto :: Package Util :: Module asn1 :: Class DerSetOf

Class DerSetOf

object --+    
         |    
 DerObject --+
             |
            DerSetOf

Class to model a DER SET OF.

An example of encoding is:

>>> from Crypto.Util.asn1 import DerBitString
>>> from binascii import hexlify, unhexlify
>>> so_der = DerSetOf([4,5])
>>> so_der.add(6)
>>> print hexlify(so_der.encode())

which will show 3109020104020105020106, the DER encoding of a SET OF with items 4,5, and 6.

For decoding:

>>> s = unhexlify(b'3109020104020105020106')
>>> try:
>>>   so_der = DerSetOf()
>>>   so_der.decode(s)
>>>   print [x for x in so_der]
>>> except (ValueError, EOFError):
>>>   print "Not a valid DER SET OF"

the output will be [4L, 5L, 6L].

Instance Methods

__init__(self, startSet=None, implicit=None)
Initialize the DER object as a SET OF.

__getitem__(self, n)

__iter__(self)

__len__(self)

add(self, elem)
Add an element to the set.

decode(self, derEle)
Decode a complete SET OF DER element, and re-initializes this object with it.

encode(self)
Return this SET OF DER element, fully encoded as a binary string.

Inherited from object: __delattr__, __format__, __getattribute__, __hash__, __new__, __reduce__, __reduce_ex__, __repr__, __setattr__, __sizeof__, __str__, __subclasshook__

Properties
Inherited from `object`: `__class__`

Method Details

init(self, startSet=None, implicit=None)
(Constructor)

Initialize the DER object as a SET OF.

Parameters:

startSet (container) - The initial set of integers or DER encoded objects.
implicit (integer) - The IMPLICIT tag to use for the encoded object. It overrides the universal tag for SET OF (17).

Overrides: object.__init__

add(self, elem)

Add an element to the set.

Parameters:

elem (byte string or integer) - An element of the same type of objects already in the set. It can be an integer or a DER encoded object.

decode(self, derEle)

Decode a complete SET OF DER element, and re-initializes this object with it.

DER INTEGERs are decoded into Python integers. Any other DER element is left undecoded; its validity is not checked.

Parameters:

derEle (byte string) - A complete DER BIT SET OF.

Raises:

ValueError - In case of parsing errors.
EOFError - If the DER element is too short.

Overrides: DerObject.decode

encode(self)

Return this SET OF DER element, fully encoded as a binary string.

Overrides: DerObject.encode

Class DerSetOf

__init__(self, startSet=None, implicit=None) (Constructor)

add(self, elem)

decode(self, derEle)

encode(self)

init(self, startSet=None, implicit=None)
(Constructor)