Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Security and eavesdropping in terahertz wireless links

Nature volume 563, pages 89–93 (2018)Cite this article

Subjects

Abstract

Resiliency against eavesdropping and other security threats has become one of the key design considerations for communication systems. As wireless systems become ubiquitous, there is an increasing need for security protocols at all levels, including software (such as encryption), hardware (such as trusted platform modules) and the physical layer (such as wave-front engineering)1,2,3,4,5. With the inevitable shift to higher carrier frequencies, especially in the terahertz range (above 100 gigahertz), an important consideration is the decreased angular divergence (that is, the increased directionality) of transmitted signals, owing to the reduced effects of diffraction on waves with shorter wavelengths. In recent years, research on wireless devices6,9,8 and systems9,12,11 that operate at terahertz frequencies has ramped up markedly. These high-frequency, narrow-angle broadcasts present a more challenging environment for eavesdroppers compared to the wide-area broadcasts used at lower frequencies12,13. However, despite the widespread assumption of improved security for high-frequency wireless data links14,15,16, the possibility of terahertz eavesdropping has not yet been characterized. A few recent studies have considered the issue at lower frequencies5,6,,12,13,17,18, but generally with the idea that the eavesdropper’s antenna must be located within the broadcast sector of the transmitting antenna, leading to the conclusion that eavesdropping becomes essentially impossible when the transmitted signal has sufficiently high directionality15. Here we demonstrate that, contrary to this expectation, an eavesdropper can intercept signals in line-of-sight transmissions, even when they are transmitted at high frequencies with narrow beams. The eavesdropper’s techniques are different from those for lower-frequency transmissions, as they involve placing an object in the path of the transmission to scatter radiation towards the eavesdropper. We also discuss one counter-measure for this eavesdropping technique, which involves characterizing the backscatter of the channel. We show that this counter-measure can be used to detect some, although not all, eavesdroppers. Our work highlights the importance of physical-layer security in terahertz wireless networks and the need for transceiver designs that incorporate new counter-measures.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Schematic of a line-of-sight transmission channel with an eavesdropper.
Fig. 2: Measured blockage and secrecy capacity for eavesdropping attacks using metal cylinders.
Fig. 3: Angular distribution of power received by Eve, using metal cylinders.
Fig. 4: Measured blockage and secrecy capacity for eavesdropping attacks using flat objects.

Similar content being viewed by others

Data availability

The data that support the findings of this study are available from the corresponding author on reasonable request.

References

  1. Shiu, Y.-S., Chang, S. Y., Wu, H.-C., Huang, S. C.-H. & Chen, H.-H. Physical layer security in wireless networks: a tutorial. IEEE Wirel. Commun. 18, 66–74 (2011).

    Article  Google Scholar 

  2. Yang, N. et al. Safeguarding 5G wireless communication networks using physical layer security. IEEE Commun. Mag. 53, 20–27 (2015).

    Article  CAS  Google Scholar 

  3. Zou, Y., Zhu, J., Wang, X. & Hanzo, L. A survey on wireless security: technical challenges, recent advances, and future trends. Proc. IEEE 104, 1727–1765 (2016).

    Article  Google Scholar 

  4. Sun, L. & Du, Q. Physical layer security with its application in 5G networks: a review. China Commun. 14, 1–14 (2017).

    Article  Google Scholar 

  5. Ju, Y., Wang, H.-M., Zheng, T.-X., Yin, Q. & Lee, M. H. Safeguarding millimeter wave communications against randomly located eavesdroppers. IEEE Trans. Wirel. Commun. 17, 2675–2689 (2018).

    Article  Google Scholar 

  6. Gao, W. et al. High-contrast terahertz wave modulation by gated graphene enhanced by extraordinary transmission through ring apertures. Nano Lett. 14, 1242–1248 (2014).

    Article  ADS  CAS  Google Scholar 

  7. Karl, N. J., McKinney, R. W., Monnai, Y., Mendis, R. & Mittleman, D. M. Frequency-division multiplexing in the terahertz range using a leaky-wave antenna. Nat. Photon. 9, 717–720 (2015).

    Article  ADS  CAS  Google Scholar 

  8. Reichel, K. S., Mendis, R. & Mittleman, D. M. A broadband terahertz waveguide T-junction variable power splitter. Sci. Rep. 6, 28925 (2016).

    Article  ADS  CAS  Google Scholar 

  9. Hermelo, M. F., Shih, P.-T. B., Steeg, M., Ng’oma, A. & Stöhr, A. Spectral efficient 64-QAM-OFDM terahertz communication link. Opt. Express 25, 19360–19370 (2017).

    Article  ADS  Google Scholar 

  10. Ma, J., Karl, N. J., Bretin, S., Ducournau, G. & Mittleman, D. M. Frequency-division multiplexer and demultiplexer for terahertz wireless links. Nat. Commun. 8, 729 (2017).

    Article  ADS  Google Scholar 

  11. Ma, J., Shrestha, R., Moeller, L. & Mittleman, D. M. Channel performance of indoor and outdoor terahertz wireless links. APL Photon. 3, 051601 (2018).

    Article  ADS  Google Scholar 

  12. Steinmetzer, D., Chen, J., Classen, J., Knightly, E. & Hollick, M. Eavesdropping with periscopes: experimental security analysis of highly directional millimeter waves. In Proc. IEEE Conf. Commun. Netw. Security (CNS) 335–343 (IEEE, 2015).

  13. Zhu, Y., Wang, L., Wong, K.-K. & Heath, R. W. Secure communications in millimeter wave ad hoc networks. IEEE Trans. Wirel. Commun. 16, 3205–3217 (2017).

    Article  Google Scholar 

  14. Federici, J. & Moeller, L. Review of terahertz and subterahertz wireless communications. J. Appl. Phys. 107, 111101 (2010).

    Article  ADS  Google Scholar 

  15. Akyildiz, I. F., Jornet, J. M. & Han, C. Terahertz band: next frontier for wireless communications. Phys. Commun. 12, 16–32 (2014).

    Article  Google Scholar 

  16. Kürner, T. & Priebe, S. Towards THz communications – status in research, standardization and regulation. J. Infrared Millim. THz Waves 35, 53–62 (2014).

    Article  Google Scholar 

  17. Vuppala, S., Biswas, S. & Ratnarajah, T. An analysis on secure communications in millimeter/micro-wave hybrid networks. IEEE Trans. Commun. 64, 3507–3519 (2016).

    Article  Google Scholar 

  18. Kim, M., Hwang, E. & Kim, J.-N. Analysis of eavesdropping attack in mmWave-based WPANs with directional antennas. Wirel. Netw. 23, 355–369 (2017).

    Article  Google Scholar 

  19. Pierpoint, M. & Rebeiz, G. M. Paving the way for 5G realization and mmWave communication systems. Mirowave J. 59, 106–108 (2016).

    Google Scholar 

  20. Xu, J. et al. Statistical analysis of path losses for sectorized wireless networks. IEEE Trans. Commun. 65, 1828–1838 (2017).

    Article  Google Scholar 

  21. Babakhani, A., Rutledge, D. B. & Hajimiri, A. Transmitter architectures based on near-field direct antenna modulation. IEEE J. Solid-State Circuits 43, 2674–2692 (2008).

    Article  ADS  Google Scholar 

  22. Djordjevic, I. B. Multidimensional OAM-based secure high-speed wireless communications. IEEE Access 5, 16416–16428 (2017).

    Article  Google Scholar 

  23. Rifà-Pous, H. & Herrera-Joancomarti, J. Computational and energy costs of cryptographic algorithms on handheld devices. Future Internet 3, 31–48 (2011).

    Article  Google Scholar 

  24. Headland, D., Monnai, Y., Abbott, D., Fumeaux, C. & Withayachumnankul, W. Tutorial: terahertz beamforming, from concept to realizations. APL Photon. 3, 051101 (2018).

    Article  ADS  Google Scholar 

  25. Song, H.-J. & Nagatsuma, T. Present and future of terahertz communications. IEEE Trans. THz Sci. Technol. 1, 256–263 (2011).

    Article  Google Scholar 

  26. Koenig, S. et al. Wireless sub-THz communication system with high data rate. Nat. Photon. 7, 977–981 (2013).

    Article  ADS  CAS  Google Scholar 

  27. Ducournau, G. et al. Ultrawide-bandwidth single-channel 0.4-THz wireless link combining broadband quasi-optic photomixer and coherent detection. IEEE Trans. THz Sci. Technol. 4, 328–337 (2014).

    Article  Google Scholar 

  28. Barros, J. & Rodrigues, M. R. D. Secrecy capacity of wireless channels. In Proc. IEEE Symp. Inform. Theory 356–360 (IEEE, 2006).

  29. Csiszár, I. & Körner, J. Broadcast channels with confidential messages. IEEE Trans. Inf. Theory 24, 339–348 (1978).

    Article  MathSciNet  Google Scholar 

  30. Petrov, V., Komarov, M., Moltchanov, D., Jornet, J. M. & Koucheryavy, Y. Interference and SINR in millimeter wave and terahertz communication systems with blocking and directional antennas. IEEE Trans. Wirel. Commun. 16, 1791–1808 (2017).

    Article  Google Scholar 

  31. Ma, J., Moeller, L. & Federici, J. F. Experimental comparison of terahertz and infrared signaling in controlled atmospheric turbulence. J. Infrared Millimeter THz Waves 36, 130–143 (2015).

    Article  Google Scholar 

  32. Kouyoumjian, R. G. & Pathak, P. H. A uniform geometrical theory of diffraction for an edge in a perfectly conducting surface. Proc. IEEE 62, 1448–1461 (1974).

    Article  ADS  Google Scholar 

  33. Dorney, T. D., Symes, W. W., Baraniuk, R. G. & Mittleman, D. M. Terahertz multistatic reflection imaging. J. Opt. Soc. Am. A 19, 1432–1442 (2002).

    Article  ADS  Google Scholar 

  34. Chen, Z. et al. 220 GHz outdoor wireless communication system based on a Schottky diode transceiver. IEICE Electron. Express 13, 1–9 (2016).

    CAS  Google Scholar 

  35. Yeh, C.-Y. & Knightly, E. W. Feasibility of passive eavesdropping in massive MIMO: an experimental approach. In Proc. IEEE Conf. Commun. Netw. Security (CNS) 1–9 (IEEE, 2018).

  36. McNamara, D. A., Pistorius, C. W. I. & Malherbe, J. A. G. Introduction to the Uniform Geometrical Theory of Diffraction (Artech House, Boston, 1990).

  37. Ung, B. S.-Y. et al. Low-cost ultra-thin broadband terahertz beam-splitter. Opt. Express 20, 4968–4978 (2012).

    Article  ADS  CAS  Google Scholar 

Download references

Acknowledgements

This work was funded in part by the US National Science Foundation, the US Army Research Office and the W. M. Keck Foundation.

Reviewer information

Nature thanks K.-Y. Lam and the other anonymous reviewer(s) for their contribution to the peer review of this work.

Author information

Authors and Affiliations

  1. School of Engineering, Brown University, Providence, RI, USA

    Jianjun Ma, Rabi Shrestha, Jacob Adelberg & Daniel M. Mittleman

  2. Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA

    Chia-Yi Yeh & Edward Knightly

  3. Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, NY, USA

    Zahed Hossain & Josep Miquel Jornet

Authors
  1. Jianjun Ma
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Rabi Shrestha
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Jacob Adelberg
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Chia-Yi Yeh
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Zahed Hossain
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Edward Knightly
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Josep Miquel Jornet
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Daniel M. Mittleman
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

D.M.M. and E.K. conceived the experiments. J.M., R.S. and J.A. performed the measurements. Z.H. and J.M.J. performed the computations shown as dotted lines in Fig. 3. D.M.M., E.K. and C.-Y.Y. analysed and interpreted the data. All authors contributed to the writing of the manuscript.

Corresponding author

Correspondence to Daniel M. Mittleman.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data figures and tables

Extended Data Table 1 Specifications for the terahertz wireless communication system
Full size table

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Ma, J., Shrestha, R., Adelberg, J. et al. Security and eavesdropping in terahertz wireless links. Nature 563, 89–93 (2018). https://doi.org/10.1038/s41586-018-0609-x

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41586-018-0609-x

Keywords

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing