从 python 中的文件一次读取一个字节

Question

I have to create a state array (4x4 matrix of 128bit in total, having each element of one byte) for implementing AES in python, how can I read one byte at a time from an input text file.

Answer 1

I'll assume you are using NumPy since you mention 4x4 matrix.

Suppose we have text.txt with " this is a TEST ø´®†˙∆\n " as its contents. We can use the void data type to work with raw data.

>>> arr = np.fromfile('text.txt', dtype='|V1')
>>> arr
array([b'\x74', b'\x68', b'\x69', b'\x73', b'\x20', b'\x69', b'\x73',
       b'\x20', b'\x61', b'\x20', b'\x54', b'\x45', b'\x53', b'\x54',
       b'\x20', b'\xC3', b'\xB8', b'\xC2', b'\xB4', b'\xC2', b'\xAE',
       b'\xE2', b'\x80', b'\xA0', b'\xCB', b'\x99', b'\xE2', b'\x88',
       b'\x86', b'\x0A'], dtype='|V1')

This results in the same data as, although ASCII is displayed as characters.

>>> with open('text.txt', 'rb') as fp:
...     byte = fp.read()
>>> byte
b'this is a TEST \xc3\xb8\xc2\xb4\xc2\xae\xe2\x80\xa0\xcb\x99\xe2\x88\x86\n'