示例#1
0
    def __init__(self, parent, value):
        """
        TESTS::

            sage: F = GF(3).algebraic_closure()
            sage: TestSuite(F.gen(2)).run(skip=['_test_pickling'])

        .. NOTE::

            The ``_test_pickling`` test has to be skipped because
            there is no coercion map between the parents of ``x``
            and ``loads(dumps(x))``.

        """
        if is_FiniteFieldElement(value):
            n = value.parent().degree()
        else:
            from sage.rings.integer import Integer
            n = Integer(1)
        self._value = parent._subfield(n).coerce(value)
        self._level = n
        FieldElement.__init__(self, parent)
    def __init__(self, parent, value):
        """
        TEST::

            sage: F = GF(3).algebraic_closure()
            sage: TestSuite(F.gen(2)).run(skip=['_test_pickling'])

        .. NOTE::

            The ``_test_pickling`` test has to be skipped because
            there is no coercion map between the parents of ``x``
            and ``loads(dumps(x))``.

        """
        if is_FiniteFieldElement(value):
            n = value.parent().degree()
        else:
            from sage.rings.integer import Integer
            n = Integer(1)
        self._value = parent._subfield(n).coerce(value)
        self._level = n
        FieldElement.__init__(self, parent)
示例#3
0
    def __init__(self, *args,  **kwargs):
        """
        Construct a substitution box (S-box) for a given lookup table
        `S`.

        INPUT:

        - ``S`` - a finite iterable defining the S-box with integer or
          finite field elements

        - ``big_endian`` - controls whether bits shall be ordered in
          big endian order (default: ``True``)

        EXAMPLES:

        We construct a 3-bit S-box where e.g. the bits (0,0,1) are
        mapped to (1,1,1).::

            sage: from sage.crypto.sbox import SBox
            sage: S = SBox(7,6,0,4,2,5,1,3); S
            (7, 6, 0, 4, 2, 5, 1, 3)

            sage: S(0)
            7

        TESTS::

            sage: from sage.crypto.sbox import SBox
            sage: S = SBox()
            Traceback (most recent call last):
            ...
            TypeError: No lookup table provided.
            sage: S = SBox(1, 2, 3)
            Traceback (most recent call last):
            ...
            TypeError: Lookup table length is not a power of 2.
            sage: S = SBox(5, 6, 0, 3, 4, 2, 1, 2)
            sage: S.n
            3
        """
        if "S" in kwargs:
            S = kwargs["S"]
        elif len(args) == 1:
            S = args[0]
        elif len(args) > 1:
            S = args
        else:
            raise TypeError("No lookup table provided.")

        _S = []
        for e in S:
            if is_FiniteFieldElement(e):
                e = e.polynomial().change_ring(ZZ).subs( e.parent().characteristic() )
            _S.append(e)
        S = _S

        if not ZZ(len(S)).is_power_of(2):
            raise TypeError("Lookup table length is not a power of 2.")
        self._S = S

        self.m = ZZ(len(S)).exact_log(2)
        self.n = ZZ(max(S)).nbits()
        self._F = GF(2)
        self._big_endian = kwargs.get("big_endian",True)

        self.differential_uniformity = self.maximal_difference_probability_absolute
示例#4
0
文件: sbox.py 项目: robertwb/sage
    def __init__(self, *args,  **kwargs):
        """
        Construct a substitution box (S-box) for a given lookup table
        `S`.

        INPUT:

        - ``S`` - a finite iterable defining the S-box with integer or
          finite field elements

        - ``big_endian`` - controls whether bits shall be ordered in
          big endian order (default: ``True``)

        EXAMPLE:

        We construct a 3-bit S-box where e.g. the bits (0,0,1) are
        mapped to (1,1,1).::

            sage: S = mq.SBox(7,6,0,4,2,5,1,3); S
            (7, 6, 0, 4, 2, 5, 1, 3)

            sage: S(0)
            7

        TESTS::

            sage: S = mq.SBox()
            Traceback (most recent call last):
            ...
            TypeError: No lookup table provided.
            sage: S = mq.SBox(1, 2, 3)
            Traceback (most recent call last):
            ...
            TypeError: Lookup table length is not a power of 2.
            sage: S = mq.SBox(5, 6, 0, 3, 4, 2, 1, 2)
            sage: S.n
            3
        """
        if "S" in kwargs:
            S = kwargs["S"]
        elif len(args) == 1:
            S = args[0]
        elif len(args) > 1:
            S = args
        else:
            raise TypeError("No lookup table provided.")

        _S = []
        for e in S:
            if is_FiniteFieldElement(e):
                e = e.polynomial().change_ring(ZZ).subs( e.parent().characteristic() )
            _S.append(e)
        S = _S

        if not ZZ(len(S)).is_power_of(2):
            raise TypeError("Lookup table length is not a power of 2.")
        self._S = S

        self.m = ZZ(len(S)).exact_log(2)
        self.n = ZZ(max(S)).nbits()
        self._F = GF(2)
        self._big_endian = kwargs.get("big_endian",True)

        self.differential_uniformity = self.maximal_difference_probability_absolute