Charles Beumier

Creating a dynamic library in C

C libraries are handy for distribution of programming work or for structuring a large development into units. In the specific case of Python programming, a C dynamic library can be a solution for a missing Python equivalent or if performance in execution time is a concern. We explain hereunder with an example the steps necessary to write a dynamic (shared) C library in Linux (tested on Ubuntu20.04). Another blog will describe how to call a C dynamic library from Python.

Read more
What is VoWiFI ("Wi-Fi Calling") ?

1. What is VoWiFi ("Wi-Fi Calling") ?

Read more
Mobile Phones: Should you be afraid of disclosing your IMSI ?

The smartphone has become so important in daily life that users should be concerned about its security. We try to explain here some reasons to be or not to be afraid about disclosing the IMSI, the subscriber identity number used in the global telecommunication network.

Read more
A bit of PIL for bit plane display

Displaying image bit planes, in particular less significant ones, is an important task to reveal some image artefacts due to image degradation or manipulation. In particular, the Least Significant Bit (LSB) of pixel values is heavily used in steganography to hide messages in a cover image. We will see in this blog how to use the Python Imaging Library (PIL) to save and display an image containing some specified bit planes of a given image.

Read more
SMS-based 2-Factor Authentication is insecure !

The US National Institute of Standards and Technology (NIST) has declared in its Digital Authentication Guideline that SMS-based two-factor authentication should be banned due to security concerns [End of SMS-based 2-Factor Authentication; Yes, It's Insecure!]. We explain why in this blog.

Read more