{"_id":"59824","ddc":["006"],"conference":{"start_date":"2025-05-12","end_date":"2025-05-14","location":"San Francisco","name":"46th IEEE Symposium on Security and Privacy"},"type":"conference","oa":"1","doi":"10.1109/SP61157.2025.00151","language":[{"iso":"eng"}],"abstract":[{"text":"HTTPS composes large parts of today’s Internet traffic and has long been subject to censorship efforts in different countries. While censors analyze the Transport Layer Security (TLS) protocol to block encrypted HTTP traffic, censorship circumvention efforts have primarily focused on other protocols such as TCP. In this paper, we hypothesize that the TLS protocol offers previously unseen opportunities for censorship circumvention techniques. We tested our hypothesis by proposing possible censorship circumvention techniques that act on the TLS protocol. To validate the effectiveness of these techniques, we evaluate their acceptance by popular TLS servers and successfully demonstrate that these techniques can circumvent censors in China and Iran. In our evaluations, we discovered 38—partially standard-compliant—distinct censorship circumvention techniques, which we could group into 11 unique categories. Additionally, we provide novel insights into how China censors TLS traffic by presenting evidence of at least three distinct censorship appliances. We suspect that other parts of China’s censorship apparatus and other censors exhibit similar structures and advocate future censorship research to anticipate them. With this work, we hope to aid people affected by censorship and stimulate further\r\nresearch into censorship circumvention using cryptographic protocols.","lang":"eng"}],"file":[{"content_type":"application/pdf","access_level":"open_access","creator":"nniklas","file_size":463431,"relation":"main_file","file_id":"59826","date_updated":"2025-05-06T13:51:45Z","file_name":"TLS_Obscurity.pdf","date_created":"2025-05-06T13:49:35Z"}],"file_date_updated":"2025-05-06T13:51:45Z","status":"public","department":[{"_id":"632"}],"date_updated":"2025-05-06T13:59:43Z","year":"2025","citation":{"mla":"Niere, Niklas, et al. “Transport Layer Obscurity: Circumventing SNI Censorship on the TLS-Layer.” <i>2025 IEEE Symposium on Security and Privacy (SP)</i>, 2025, doi:<a href=\"https://doi.org/10.1109/SP61157.2025.00151\">10.1109/SP61157.2025.00151</a>.","chicago":"Niere, Niklas, Felix Lange, Robert Merget, and Juraj Somorovsky. “Transport Layer Obscurity: Circumventing SNI Censorship on the TLS-Layer.” In <i>2025 IEEE Symposium on Security and Privacy (SP)</i>, 2025. <a href=\"https://doi.org/10.1109/SP61157.2025.00151\">https://doi.org/10.1109/SP61157.2025.00151</a>.","apa":"Niere, N., Lange, F., Merget, R., &#38; Somorovsky, J. (2025). Transport Layer Obscurity: Circumventing SNI Censorship on the TLS-Layer. <i>2025 IEEE Symposium on Security and Privacy (SP)</i>. 46th IEEE Symposium on Security and Privacy, San Francisco. <a href=\"https://doi.org/10.1109/SP61157.2025.00151\">https://doi.org/10.1109/SP61157.2025.00151</a>","short":"N. Niere, F. Lange, R. Merget, J. Somorovsky, in: 2025 IEEE Symposium on Security and Privacy (SP), 2025.","ieee":"N. Niere, F. Lange, R. Merget, and J. Somorovsky, “Transport Layer Obscurity: Circumventing SNI Censorship on the TLS-Layer,” presented at the 46th IEEE Symposium on Security and Privacy, San Francisco, 2025, doi: <a href=\"https://doi.org/10.1109/SP61157.2025.00151\">10.1109/SP61157.2025.00151</a>.","bibtex":"@inproceedings{Niere_Lange_Merget_Somorovsky_2025, title={Transport Layer Obscurity: Circumventing SNI Censorship on the TLS-Layer}, DOI={<a href=\"https://doi.org/10.1109/SP61157.2025.00151\">10.1109/SP61157.2025.00151</a>}, booktitle={2025 IEEE Symposium on Security and Privacy (SP)}, author={Niere, Niklas and Lange, Felix and Merget, Robert and Somorovsky, Juraj}, year={2025} }","ama":"Niere N, Lange F, Merget R, Somorovsky J. Transport Layer Obscurity: Circumventing SNI Censorship on the TLS-Layer. In: <i>2025 IEEE Symposium on Security and Privacy (SP)</i>. ; 2025. doi:<a href=\"https://doi.org/10.1109/SP61157.2025.00151\">10.1109/SP61157.2025.00151</a>"},"title":"Transport Layer Obscurity: Circumventing SNI Censorship on the TLS-Layer","date_created":"2025-05-06T13:40:50Z","has_accepted_license":"1","publication":"2025 IEEE Symposium on Security and Privacy (SP)","user_id":"63563","author":[{"id":"63563","last_name":"Niere","full_name":"Niere, Niklas","first_name":"Niklas"},{"first_name":"Felix","full_name":"Lange, Felix","last_name":"Lange","id":"67893"},{"first_name":"Robert","full_name":"Merget, Robert","last_name":"Merget"},{"orcid":"0000-0002-3593-7720","first_name":"Juraj","last_name":"Somorovsky","full_name":"Somorovsky, Juraj","id":"83504"}]}