{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,10]],"date-time":"2026-04-10T16:11:13Z","timestamp":1775837473058,"version":"3.50.1"},"reference-count":43,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2021,3,21]],"date-time":"2021-03-21T00:00:00Z","timestamp":1616284800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This paper presents a thorough comparison of the Transport Layer Security (TLS) v1.2 and Datagram TLS (DTLS) v1.2 handshake in 6TiSCH networks. TLS and DTLS play a crucial role in protecting daily Internet traffic, while 6TiSCH is a major low-power link layer technology for the IoT. In recent years, DTLS has been the de-facto security protocol to protect IoT application traffic, mainly because it runs over lightweight, unreliable transport protocols, i.e., UDP. However, unlike the DTLS record layer, the handshake requires reliable message delivery. It, therefore, incorporates sequence numbers, a retransmission timer, and a fragmentation algorithm. Our goal is to study how well these mechanisms perform, in the constrained setting of 6TiSCH, compared to TCP\u2019s reliability algorithms, relied upon by TLS. We port the mbedTLS library to OpenWSN, a 6TiSCH reference implementation, and deploy the code on the state-of-the-art OpenMote platform. We show that, when the peers use an ideal channel, the DTLS handshake uses up to 800 less and completes 0.6 s faster. Nonetheless, using an unreliable communication link, the DTLS handshake duration suffers a performance penalty of roughly 45%, while TLS\u2019 handshake duration degrades by merely 15%. Similarly, the number of exchanged bytes doubles for DTLS while for TLS the increase is limited to 15%. The results indicate that IoT product developers should account for network characteristics when selecting a security protocol. Neglecting to do so can negatively impact the battery lifetime of the entire constrained network.<\/jats:p>","DOI":"10.3390\/s21062192","type":"journal-article","created":{"date-parts":[[2021,3,21]],"date-time":"2021-03-21T23:47:41Z","timestamp":1616370461000},"page":"2192","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Performance of the Transport Layer Security Handshake Over 6TiSCH"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9438-6471","authenticated-orcid":false,"given":"Timothy","family":"Claeys","sequence":"first","affiliation":[{"name":"Inria, 2 Rue Simone IFF, 75012 Paris, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7700-9121","authenticated-orcid":false,"given":"Mali\u0161a","family":"Vu\u010dini\u0107","sequence":"additional","affiliation":[{"name":"Inria, 2 Rue Simone IFF, 75012 Paris, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3695-9315","authenticated-orcid":false,"given":"Thomas","family":"Watteyne","sequence":"additional","affiliation":[{"name":"Inria, 2 Rue Simone IFF, 75012 Paris, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8665-6603","authenticated-orcid":false,"given":"Franck","family":"Rousseau","sequence":"additional","affiliation":[{"name":"Univ. Grenoble Alpes, CNRS, Grenoble INP, LIG, F-38000 Grenoble, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6502-9689","authenticated-orcid":false,"given":"Bernard","family":"Tourancheau","sequence":"additional","affiliation":[{"name":"Univ. Grenoble Alpes, CNRS, Grenoble INP, LIG, F-38000 Grenoble, France"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,3,21]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"595","DOI":"10.1109\/COMST.2019.2939407","article-title":"IETF 6TiSCH: A Tutorial","volume":"22","author":"Vilajosana","year":"2019","journal-title":"IEEE Commun. Surv. Tutor."},{"key":"ref_2","unstructured":"RFC (2021, February 01). Object Security for Constrained RESTful Environments (OSCORE), Available online: https:\/\/datatracker.ietf.org\/doc\/rfc8613\/."},{"key":"ref_3","unstructured":"RFC (2021, February 01). Ephemeral Diffie-Hellman Over COSE (EDHOC), Available online: https:\/\/datatracker.ietf.org\/doc\/draft-ietf-lake-edhoc\/05\/."},{"key":"ref_4","unstructured":"RFC (2021, February 01). The Transport Layer Security (TLS) Protocol Version 1.2, Available online: https:\/\/datatracker.ietf.org\/doc\/rfc5246\/."},{"key":"ref_5","unstructured":"RFC (2021, February 01). Datagram Transport Layer Security Version 1.2, Available online: https:\/\/datatracker.ietf.org\/doc\/rfc6347\/."},{"key":"ref_6","unstructured":"ARM (2021, February 01). ARM MBEDTLS, Available online: https:\/\/tls.mbed.org\/."},{"key":"ref_7","unstructured":"wolfSSL (2021, February 01). wolfSSL, Available online: https:\/\/www.wolfssl.com\/."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"IEEE (2016). IEEE Standard for Low-Rate Wireless Networks, IEEE. IEEE Std 802.15.4-2015 (Revision of IEEE Std 802.15.4-2011).","DOI":"10.1109\/TITB.2011.2166649"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Watteyne, T., Mehta, A., and Pister, K. (2009, January 26\u201330). Reliability through Frequency Diversity: Why Channel Hopping Makes Sense. Proceedings of the Symposium on Performance Evaluation of Wireless Ad hoc, Sensor and Ubiquitous Networks (PE-WASUN), Tenerife, Canary Islands, Spain.","DOI":"10.1145\/1641876.1641898"},{"key":"ref_10","unstructured":"OpenWSN (2021, February 01). OpenWSN, Available online: https:\/\/openwsn.atlassian.net\/wiki\/spaces\/OW\/overview."},{"key":"ref_11","unstructured":"RFC (2021, February 01). Performance Enhancing Proxies Intended to Mitigate Link-Related Degradations, Available online: https:\/\/datatracker.ietf.org\/doc\/rfc3135\/."},{"key":"ref_12","unstructured":"IEEE (2016). IEEE Standard for Local and Metropolitan Area Networks\u2014Part 15.4: Low-Rate Wireless Personal Area Networks (LR-WPANs) Amendment 1: MAC Sublayer, IEEE. Technical Report 802.15.4."},{"key":"ref_13","unstructured":"RFC (2021, February 01). 6TiSCH Operation Sublayer (6top) Protocol (6P), Available online: https:\/\/datatracker.ietf.org\/doc\/rfc8480\/."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1153","DOI":"10.1109\/JPROC.2019.2906404","article-title":"6TiSCH: Industrial Performance for IPv6 Internet-of-Things Networks","volume":"107","author":"Vilajosana","year":"2019","journal-title":"Proc. IEEE"},{"key":"ref_15","unstructured":"RFC (2021, February 01). Internet Protocol, Version 6 (IPv6) Specification, Available online: https:\/\/datatracker.ietf.org\/doc\/rfc8200\/."},{"key":"ref_16","unstructured":"RFC (2021, February 01). 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A Powerful System-On-Chip for 2.4-GHz IEEE 802.15.4-2006 and ZigBee Applications, Available online: https:\/\/www.ti.com\/product\/CC2538."},{"key":"ref_22","unstructured":"RFC (2021, February 01). TCP Selective Acknowledgment Options, Available online: https:\/\/datatracker.ietf.org\/doc\/rfc2018\/."},{"key":"ref_23","unstructured":"RFC (2021, February 01). Record Size Limit Extension for TLS, Available online: https:\/\/datatracker.ietf.org\/doc\/rfc8449\/."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"35","DOI":"10.1109\/MCOMSTD.2019.1800029","article-title":"6LoWPAN Fragment Forwarding","volume":"3","author":"Tanaka","year":"2019","journal-title":"IEEE Commun. Stand. Mag."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1006","DOI":"10.1109\/LCOMM.2016.2546880","article-title":"Distributed PID-based Scheduling for 6TiSCH Networks","volume":"20","author":"Chang","year":"2016","journal-title":"IEEE Commun. Lett."},{"key":"ref_26","unstructured":"RFC (2021, February 01). Increasing TCP\u2019s Initial Window, Available online: https:\/\/datatracker.ietf.org\/doc\/rfc3390\/."},{"key":"ref_27","unstructured":"RFC (2021, February 01). Increasing TCP\u2019s Initial Window, Available online: https:\/\/datatracker.ietf.org\/doc\/rfc6928\/."},{"key":"ref_28","unstructured":"RFC (2021, February 01). Datagram Congestion Control Protocol (DCCP), Available online: https:\/\/datatracker.ietf.org\/doc\/rfc4340\/."},{"key":"ref_29","unstructured":"RFC (2021, February 01). Computing TCP\u2019s Retransmission Timer, Available online: https:\/\/datatracker.ietf.org\/doc\/rfc6259\/."},{"key":"ref_30","unstructured":"RFC (2021, February 01). The Transport Layer Security (TLS) Protocol Version 1.3, Available online: https:\/\/datatracker.ietf.org\/doc\/rfc8446\/."},{"key":"ref_31","unstructured":"RFC (2021, February 01). The Datagram Transport Layer Security (DTLS) Protocol Version 1.3, Available online: https:\/\/datatracker.ietf.org\/doc\/draft-ietf-tls-dtls13\/."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Capossele, A., Cervo, V., De Cicco, G., and Petrioli, C. (2015, January 8\u201312). Security as a CoAP resource: An optimized DTLS implementation for the IoT. Proceedings of the IEEE International Conference on Communications (ICC), London, UK.","DOI":"10.1109\/ICC.2015.7248379"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1270","DOI":"10.1109\/TASE.2015.2511301","article-title":"S3K: Scalable security with symmetric keys\u2014DTLS key establishment for the Internet of Things","volume":"13","author":"Raza","year":"2016","journal-title":"IEEE Trans. Autom. Sci. Eng."},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Bhattacharyya, A., Bose, T., Bandyopadhyay, S., Ukil, A., and Pal, A. (2015, January 24\u201327). LESS: Lightweight Establishment of Secure Session: A Cross-Layer Approach Using CoAP and DTLS-PSK Channel Encryption. Proceedings of the International Conference on Advanced Information Networking and Applications (AINA), Gwangju, Korea.","DOI":"10.1109\/WAINA.2015.52"},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Lessa dos Santos, G., Guimaraes, V.T., da Cunha Rodrigues, G., Granville, L.Z., and Tarouco, L.M.R. (2015, January 6\u20139). A DTLS-based security architecture for the Internet of Things. Proceedings of the Symposium on Computers and Communication (ISCC), Larnaca, Cyprus.","DOI":"10.1109\/ISCC.2015.7405613"},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Vu\u010dini\u0107, M., Tourancheau, B., Watteyne, T., Rousseau, F., Duda, A., Guizzetti, R., and Damon, L. (September, January 30). DTLS Performance in Duty-Cycled Networks. Proceedings of the 2015 IEEE 26th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), Hong Kong, China.","DOI":"10.1109\/PIMRC.2015.7343505"},{"key":"ref_37","unstructured":"Buettner, M., Yee, G.V., Anderson, E., and Han, R. (November, January 31). X-MAC: A short preamble MAC protocol for duty-cycled wireless sensor networks. Proceedings of the 4th International Conference on Embedded Networked Sensor Systems, Boulder, CO, USA."},{"key":"ref_38","unstructured":"IEEE (2020). IEEE Std 802.15.4-2020 for Low-Rate Wireless Networks (Revision of IEEE Std 802.15.4-2015), IEEE. Technical Report 802.15.4."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Osterlind, F., Dunkels, A., Eriksson, J., Finne, N., and Voigt, T. (2006, January 14\u201316). Cross-level sensor network simulation with COOJA. Proceedings of the 2006 31st IEEE Conference on Local Computer Networks, Tampa, FL, USA.","DOI":"10.1109\/LCN.2006.322172"},{"key":"ref_40","unstructured":"RFC (2021, February 01). Transport Layer Security (TLS) \/ Datagram Transport Layer Security (DTLS) Profiles for the Internet of Things, Available online: https:\/\/datatracker.ietf.org\/doc\/rfc7925\/."},{"key":"ref_41","unstructured":"RFC (2021, February 01). Transport Layer Security (TLS) Session Resumption without Server-Side State, Available online: https:\/\/datatracker.ietf.org\/doc\/rfc5077\/."},{"key":"ref_42","unstructured":"RFC (2021, February 01). Transport Layer Security (TLS) False Start, Available online: https:\/\/datatracker.ietf.org\/doc\/rfc7918\/."},{"key":"ref_43","unstructured":"RFC (2021, February 01). Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS) Heartbeat Extension, Available online: https:\/\/datatracker.ietf.org\/doc\/rfc6520\/."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/21\/6\/2192\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T05:38:45Z","timestamp":1760161125000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/21\/6\/2192"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,3,21]]},"references-count":43,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2021,3]]}},"alternative-id":["s21062192"],"URL":"https:\/\/doi.org\/10.3390\/s21062192","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,3,21]]}}}