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Python _counter._newLE方法代码示例

本文整理汇总了Python中Crypto.Util._counter._newLE方法的典型用法代码示例。如果您正苦于以下问题:Python _counter._newLE方法的具体用法?Python _counter._newLE怎么用?Python _counter._newLE使用的例子?那么, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在Crypto.Util._counter的用法示例。


在下文中一共展示了_counter._newLE方法的1个代码示例,这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞,您的评价将有助于系统推荐出更棒的Python代码示例。

示例1: new

# 需要导入模块: from Crypto.Util import _counter [as 别名]
# 或者: from Crypto.Util._counter import _newLE [as 别名]
def new(nbits, prefix=b(""), suffix=b(""), initial_value=1, overflow=0, little_endian=False, allow_wraparound=False, disable_shortcut=False):
    """Create a stateful counter block function suitable for CTR encryption modes.

    Each call to the function returns the next counter block.
    Each counter block is made up by three parts::
 
      prefix || counter value || postfix

    The counter value is incremented by one at each call.

    :Parameters:
      nbits : integer
        Length of the desired counter, in bits. It must be a multiple of 8.
      prefix : byte string
        The constant prefix of the counter block. By default, no prefix is
        used.
      suffix : byte string
        The constant postfix of the counter block. By default, no suffix is
        used.
      initial_value : integer
        The initial value of the counter. Default value is 1.
      little_endian : boolean
        If True, the counter number will be encoded in little endian format.
        If False (default), in big endian format.
      allow_wraparound : boolean
        If True, the function will raise an *OverflowError* exception as soon
        as the counter wraps around. If False (default), the counter will
        simply restart from zero.
      disable_shortcut : boolean
        If True, do not make ciphers from `Crypto.Cipher` bypass the Python
        layer when invoking the counter block function.
        If False (default), bypass the Python layer.
    :Returns:
      The counter block function.
    """

    # Sanity-check the message size
    (nbytes, remainder) = divmod(nbits, 8)
    if remainder != 0:
        # In the future, we might support arbitrary bit lengths, but for now we don't.
        raise ValueError("nbits must be a multiple of 8; got %d" % (nbits,))
    if nbytes < 1:
        raise ValueError("nbits too small")
    elif nbytes > 0xffff:
        raise ValueError("nbits too large")

    initval = _encode(initial_value, nbytes, little_endian)

    if little_endian:
        return _counter._newLE(bstr(prefix), bstr(suffix), initval, allow_wraparound=allow_wraparound, disable_shortcut=disable_shortcut)
    else:
        return _counter._newBE(bstr(prefix), bstr(suffix), initval, allow_wraparound=allow_wraparound, disable_shortcut=disable_shortcut) 
开发者ID:adde88,项目名称:hostapd-mana,代码行数:54,代码来源:Counter.py


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