rsa.py 文件源码

def encrypt(self, data, offset=None, length=None):
        """Encrypts the given data with the current key"""
        if offset is None:
            offset = 0
        if length is None:
            length = len(data)

        with BinaryWriter() as writer:
            # Write SHA
            writer.write(sha1(data[offset:offset + length]).digest())
            # Write data
            writer.write(data[offset:offset + length])
            # Add padding if required
            if length < 235:
                writer.write(os.urandom(235 - length))

            result = int.from_bytes(writer.get_bytes(), byteorder='big')
            result = pow(result, self.e, self.m)

            # If the result byte count is less than 256, since the byte order is big,
            # the non-used bytes on the left will be 0 and act as padding,
            # without need of any additional checks
            return int.to_bytes(
                result, length=256, byteorder='big', signed=False)