  The Cipher Block Chaining (CBC) mode of encryption was invented in 1976, and
it is currently one of the most commonly used mode. In our previous research
works, we have proven that the CBC mode of operation exhibits, under some
conditions, a chaotic behavior. The dynamics of this mode has been deeply
investigated later, both qualitatively and quantitatively, using the rigorous
mathematical topology field of research. In this article, which is an extension
of our previous work, we intend to compute a new important quantitative
property concerning our chaotic CBC mode of operation, which is the Lyapunov
exponent.
