Authors:
Cristina-Loredana Duta
1
;
Laura Gheorghe
2
and
Nicolae Tapus
1
Affiliations:
1
University Politehnica of Bucharest, Romania
;
2
Academy of Romanian Scientists, Romania
Keyword(s):
Digital Signal Processor, Voice Encryption, Blackfin Processor, TMS320C6X Processor, AES, RSA, NTRU.
Abstract:
In the last decades, digital communications and network technologies have been growing rapidly, which
makes secure speech communication an important issue. Regardless of the communication purposes, military,
business or personal, people want a high level of security during their conversations. In this context, many
voice encryption methods have been developed, which are based on cryptographic algorithms. One of the
major issues regarding these algorithms is to identify those that can ensure high throughput when dealing with
reduced bandwidth of the communication channel. A solution is to use resource constrained embedded
systems because they are designed such that they consume little system resources, providing at the same time
very good performances. To fulfil all the strict requirements, hardware and software optimizations should be
performed by taking into consideration the complexity of the chosen algorithm, the mapping between the
selected architecture and the cryptographic algo
rithm, the selected arithmetic unit (floating point or fixed
point) and so on. The purpose of this paper is to compare and evaluate based on several criteria the Digital
Signal Processor (DSP) implementations of three voice encryption algorithms in real time. The algorithms
can be divided into two categories: asymmetric ciphers (NTRU and RSA) and symmetric ciphers (AES). The
parameters taken into consideration for comparison between these ciphers are: encryption, decryption and
delay time, complexity, packet lost and security level. All the previously mentioned algorithms were
implemented on Blackfin and TMS320C6x processors. Making hardware and software level optimizations,
we were able to reduce encryption/decryption/delay time, as well as to reduce the energy consumed. The
purpose of this paper is to determine which is the best system hardware (DSP platform) and which encryption
algorithm is feasible, safe and best suited for real-time voice encryption.
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