The closer the entropy value is to 8.0, the higher the entropy. However in the real world, files that contain random data have no utility in a file system, therefore it is highly probable that files with high entropy are actually encrypted or compressed.Ī contributor on wrote a python program called file_entropy.py that can be run from the shell command line by with the following command:
![calculating entropy calculating entropy](https://raw.githubusercontent.com/elsentjhung/elsentjhung.github.io/master/_figures/irreversibility2.jpg)
This concept of advantage applies to the mathematical analysis of encryption algorithms. In the field of cryptology, there are formal proofs that show that if an adversary can correctly distinguish an encrypted file from a file that is truly random with a greater than 50% probability then it is said that he has “the advantage.” The adversary can then exploit that advantage and possibly break the encryption. Determining the entropy of a file is also useful to detect if it is likely to be encrypted. Therefore, the more entropy in the data file, the less it can be compressed. In simple terms, a file is compressed by replacing patterns of bits with shorter patterns of bits. Shannon in applied the concept to digital communications his 1948 paper, “A Mathematical Theory of Communication.” Shannon was interested in determining the theoretical maximum amount that a digital file could be compressed. The concept originated in the study of thermodynamics, but Claude E. Entropy is the measurement of the randomness.