Query from User: What makes a text file numeric in nature?
Exploring the Past for Cybersecurity Insights
In the cybersecurity world, the practice of securing systems by concealing their workings, often referred to as 'security through obscurity', is a topic of ongoing debate. To delve into its implications, we recently published an article (Part 1) that examined a historical case study: the content scramble system (CSS).
Originally developed to control piracy, CSS proved to be problematic, preventing users from copying their legally-obtained DVDs, using them on certain operating systems, and playing them in different countries. When its secretive algorithm was exposed in 2001, the consortium behind CSS tried to use the law to restrict its publication, arguing that making it illegal to possess or distribute the source code would protect its security.
However, this approach was short-sighted. Public scrutiny of the CSS algorithm had already revealed its inadequacies before the legal action. To drive this point home, a prominent cryptographer published a prime number that could be traced back to the leaked CSS source code. By doing so, they aimed to raise questions about the practicality of making a number—let alone a mathematical construct integral to a system's structure—illegal.
Cybersecurity history teems with such ironic instances, serving as valuable learning opportunities. By understanding past mistakes, we can better navigate the complexities of modern cybersecurity while being entertained by its unique quirks.
Understanding the Technique
A reader contacted us with an intriguing question about converting complex binary data into a large number for analysis purposes.
Typically, computer files contain data that spans each of the available 8 bits in a byte. This data can be decoded using different tables to create readable characters (e.g., ASCII). Non-text files, however, can store any number from 0 to 255 in each byte.
To convert this sequence of non-text bytes into a single massive number, we can apply the same method used for years, decimal numbers: treating individual bytes as 'digits' in a base 256 system. This system is possible because each 8-bit byte enables 256 different combinations, just as three decimal digits (0-9) let you denote one thousand different numbers.
Unfortunately, most programming languages set limitations on the number of bits used for calculations. For example, in Lua, a popular and powerful scripting language used for cybersecurity tools, integer calculations are limited to 64 bits, leading to issues such as integer overflow when handling massive numbers.
To derive a manageable but still enormous number from the CSS source code, one can compress it using a tool like gzip and then artificially extend it to find a nearby prime number. Though this method does not guarantee a prime number, it demonstrates the limitations of attempting to protect data through legislation.
Takeaways
Cybersecurity history is replete with instances where well-intentioned but misguided efforts have surface-level appeal but ultimately fail when the consequences are fully scrutinized. Understanding these past mistakes is crucial in addressing the challenges of modern cybersecurity and navigating its intricate landscape.
In the realm of education-and-self-development, delving into the techniques used in the past for cybersecurity, such as the conversion of complex binary data into a large number for analysis purposes, can provide invaluable insights for contemporary cybersecurity practitioners. This understanding, coupled with the realization of the limitations encountered when trying to protect data through legislation, as seen in the debatable use of the law to restrict the publication of the CSS source code, further highlights the importance of both technology and education-and-self-development in mastering the complexities of modern cybersecurity.
