Performance Comparison of Voice Encryption Algorithms Implemented on Blackfin Platform

Nowadays, secure speech communications have become a fundamental issue, due to the rapid development of digital communications and networking technologies. People want high security level during their communications, especially for military and business purpose. For instance, in order to operate properly and effective in a hostile environment is mandatory to have a secure military communication. The methods that are currently available for voice encryption include the use of cryptographic algorithms (which ensure secure data transmission and reception). However, taking into consideration the problem of the bandwidth of the communication channel (which appears frequently in military applications), it is important to identify encryption algorithms that ensure high throughput and low bit-rate speech compression methods. Various speech encryption methods have strict requirements such as power consumption, size, voltage supply, which are difficult to fulfil. A solution to meet these constraints is to perform optimization at all levels, starting from the algorithm design, continuing with the system and circuit structure and reaching also the design of the cell library. More exactly, these optimizations depend on the modification of the encryption algorithm selected for the applications (in order to reduce its computational complexity), the algorithm chosen, the arithmetic unit selected (fixed-point or floating-point), the mapping between the selected architecture and the cryptographic algorithm. This paper describes a comparison regarding the performance of various speech encryption algorithms implemented on Digital Signal Processor (DSP) platform. These algorithms are from different categories, such as: stream ciphers (Grain v1, Trivium, Mickey 2.0 and SOSEMANUK), block ciphers (Advanced Encryption Standard - AES and Data Encryption Standard - DES) and dedicated algorithms for voice encryption (Robust Secure Coder, scrambling encryption and encryption algorithm based on chaotic map and Blowfish). All the previously mentioned algorithms where implemented on Blackfin 537 (a fixed point DSP) and careful optimizations were performed to fulfil real time requirements. The goal of this paper was to evaluate all these algorithms to determine which one is the best suited for applications that require secure real time communications.