High-uncertainty audio signal encryption based on the Collatz conjecture.

Transmission of protected content via commercial channels is a common problem observed in information security. The secrecy of such content can be preserved using various encryption techniques. This study proposes a novel speech encryption method that provides high level of security and uncertainty to the encrypted data using a variable-length encoding technique based on the Collatz conjecture. The efficiency of the proposed method is evaluated by testing 500 encrypted audio files in terms of data correlation, uncertainty and disorder, time expansion ratio, computational cost, security key space size and key sensitivity. Results indicate that the uncertainty levels (7.5) and disorder levels (1.2) of the encrypted files are almost similar to the maximum possible entropy and disorder levels of 8 and 2, respectively. Compared with other approaches, this method has larger key space with extremely higher key sensitivity. Thus, the proposed method can be essentially used in information security because it produces encrypted signals with high level of security and uncertainty. [ABSTRACT FROM AUTHOR]