Real-time DSP Implementations of Voice Encryption Algorithms

Cristina-Loredana Duta, Laura Gheorghe, Nicolae Tapus


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 algorithm, 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.


  1. Pedre, S., Krajnik, T., Todorovich, E., Borensztejn, P., 2016. Accelerating embedded image processing for real time: a case study. In Journal of Real-Time Image Processing, Vol. 11, No. 2, pp. 349-374.
  2. Joao, J. A., Mutlu, O., Patt, Y. N., 2009. Flexible Reference-Counting-Based Hardware Acceleration for Garbage Collection. In Proceedings of ISCA 2009, pp. 1-11.
  3. Daemen J., Rijmen V., 2001. Rijndael: The Advanced Encryption Standard. In D r. Dobb's Journal, pp. 137- 139.
  4. Biryukov, A., Khovratovich, D., 2009. Related-key Cryptanalysis of the Full AES-192 and AES-256. In Cryptology ePrint Archive: Report 2009/317.
  5. Bogdanov, A., Khovratovich, D., Rechberger, C., 2011. Biclique Cryptanalysis of the Full AES. In Advances in Cryptology - ASIACRYPT 2011, Vol. 7073, pp. 344- 371.
  6. Rivest, R., Shamir, A., Adleman, L., 1978. A Method for Obtaining Digital Signatures and Public-Key Cryptosystems. In Communications of the ACM, Vol. 21, No. 2, pp. 120-126.
  7. Rivest, L. R., Kaliski, B., 2003. RSA Problem. In Encyclopedia of Cryptography and Security, chapter RSA Problem.
  8. US Patent 6081597, 1996. Public key cryptosystem method and apparatus. In Google Patents.
  9. Sakshaug, H., 2007. Security Analysis of the NTRUEncrypt Public Key Encryption Scheme. Available at 258846/426901_FULLTEXT01.pdf (Last Accessed: October 2016).
  10. ADSP-BF537 Blackfin Processor Hardware Reference Manual, Revision 3.4, 2013. Available at http:// processor-manuals/ADSP-BF537_hwr_rev3.4.pdf (Last Accessed: October 2016).
  11. TMS320C6711, Floating-Point Digital Signal Procesors, 2005. Available at /tms320c6711c.pdf (Last Accessed: October 2016).
  12. Wollinger, T., Guajardo, J., Paar, C., 2003. Cryptography in embedded systems: An overview. In Proceedings of the Embedded World 2003.
  13. Fiskiran, M., Lee, R.B., 2002. Workload characterization of elliptic curve cryptography and other network security algorithms for constrained environments. In Proceedings of the IEEE International Workshop on Workload Characterization (WWC-5), pp. 127-137.
  14. Wollinger, T., Wang, M., Guajardo, J., Paar, C., 2000. How well are high-end dsps suited for the aes algorithms? aes algorithms on the tms320c6x dsp. In AES Candidate Conference, pp. 94-105.
  15. Thulasimani, L., Madheswaran, M., 2010. Design And Implementation of Reconfigurable Rijndael Encryption algorithms for Reconfigurable Mobile Terminals. In International Journal on Computer Science and Engineering, Vol. 2, No. 4, pp. 1003-1011.
  16. Verna, H.K., Singh, R. K., 2012. Performance Analysis of RC6, Twofish and Rijndael Block Cipher Algorithms. In International Journal of Computer Applications, Vol. 42, No. 16, pp. 1-7.
  17. Itoh, K., Takenaka, M., Torii, N., Temma, S., Kurihara, Y., 1999. Fast implementation of public-key cryptography on a dsp tms320c6201. In CHES 7899: Proceedings of the First International Workshop on Cryptographic Hardware and Embedded Systems, pp. 61-72.
  18. Grobschadl, J., Tillich, S., Rechberger, C., Hofmann, M., Medwed, M., 2007. Energy evaluation of software implementations of block ciphers under memory constraints. In DATE, pp. 1110-1115.
  19. Yen, SM., Kim, S., Lim, S., Moon, S. J., 2003. RSA speedup with Chinese remainder theorem immune against hardware fault cryptanalysis. In IEEE Transactions on Computers, Vol. 52, No.4, pp. 461--472.
  20. Er, M. H., Wong, DJ., Sethu, A., Ngeow, KS., 1991. Design and implementation of RSA cryptosystem using multiple DSP chips. In IEEE International Symposium on Circuits and Systems, Vol. 1, pp. 49--52.
  21. Ambika, D., Radha, V., 2012. Secure Speech Communication- A Review. In International Journal of Engineering Research and Applications, Vol. 2, No. 5, pp. 1044-1049.
  22. Bassalee W., Kaeli D., 2008. Resource-Conscious Optimization of Cryptographic Algorithms on an Embedded Architecture. Available at http:// 08bassalee.pdf (Last Accessed: October 2016).

Paper Citation

in Harvard Style

Duta C., Gheorghe L. and Tapus N. (2017). Real-time DSP Implementations of Voice Encryption Algorithms . In Proceedings of the 3rd International Conference on Information Systems Security and Privacy - Volume 1: ICISSP, ISBN 978-989-758-209-7, pages 439-446. DOI: 10.5220/0006208304390446

in Bibtex Style

author={Cristina-Loredana Duta and Laura Gheorghe and Nicolae Tapus},
title={Real-time DSP Implementations of Voice Encryption Algorithms},
booktitle={Proceedings of the 3rd International Conference on Information Systems Security and Privacy - Volume 1: ICISSP,},

in EndNote Style

JO - Proceedings of the 3rd International Conference on Information Systems Security and Privacy - Volume 1: ICISSP,
TI - Real-time DSP Implementations of Voice Encryption Algorithms
SN - 978-989-758-209-7
AU - Duta C.
AU - Gheorghe L.
AU - Tapus N.
PY - 2017
SP - 439
EP - 446
DO - 10.5220/0006208304390446