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Stealth Key Exchange and Confined Access to the Record Protocol Data in TLS 1.3

Fischlin, Marc
eds.: Meng, Weizhi ; Jensen, Christian Damsgaard ; Cremers, Cas ; Kirda, Engin (2023)
Stealth Key Exchange and Confined Access to the Record Protocol Data in TLS 1.3.
2023 ACM SIGSAC Conference on Computer and Communications Security (CCS 2023). Copenhagen, Denmark (26.-30.11.2023)
doi: 10.1145/3576915.3623099
Conference or Workshop Item, Bibliographie

Abstract

We show how to embed a covert key exchange sub protocol within a regular TLS 1.3 execution, generating a stealth key in addition to the regular session keys. The idea, which has appeared in the literature before, is to use the exchanged nonces to transport another key value. Our contribution is to give a rigorous model and analysis of the security of such embedded key exchanges, requiring that the stealth key remains secure even if the regular key is under adversarial control. Specifically for our stealth version of the TLS 1.3 protocol we show that this extra key is secure in this setting under the common assumptions about the TLS protocol.

As an application of stealth key exchange we discuss sanitizable channel protocols, where a designated party can partly access and modify payload data in a channel protocol. This may be, for instance, an intrusion detection system monitoring the incoming traffic for malicious content and putting suspicious parts in quarantine. The noteworthy feature, inherited from the stealth key exchange part, is that the sender and receiver can use the extra key to still communicate securely and covertly within the sanitizable channel, e.g., by pre-encrypting confidential parts and making only dedicated parts available to the sanitizer. We discuss how such sanitizable channels can be implemented with authenticated encryption schemes like GCM or ChaChaPoly. In combination with our stealth key exchange protocol, we thus derive a full-fledged sanitizable connection protocol, including key establishment, which perfectly complies with regular TLS 1.3 traffic on the network level. We also assess the potential effectiveness of the approach for the intrusion detection system Snort.

Item Type: Conference or Workshop Item
Erschienen: 2023
Editors: Meng, Weizhi ; Jensen, Christian Damsgaard ; Cremers, Cas ; Kirda, Engin
Creators: Fischlin, Marc
Type of entry: Bibliographie
Title: Stealth Key Exchange and Confined Access to the Record Protocol Data in TLS 1.3
Language: English
Date: 21 November 2023
Publisher: ACM
Book Title: CCS'23: Proceedings of the 2023 ACM SIGSAC Conference on Computer and Communications Security
Event Title: 2023 ACM SIGSAC Conference on Computer and Communications Security (CCS 2023)
Event Location: Copenhagen, Denmark
Event Dates: 26.-30.11.2023
DOI: 10.1145/3576915.3623099
Abstract:

We show how to embed a covert key exchange sub protocol within a regular TLS 1.3 execution, generating a stealth key in addition to the regular session keys. The idea, which has appeared in the literature before, is to use the exchanged nonces to transport another key value. Our contribution is to give a rigorous model and analysis of the security of such embedded key exchanges, requiring that the stealth key remains secure even if the regular key is under adversarial control. Specifically for our stealth version of the TLS 1.3 protocol we show that this extra key is secure in this setting under the common assumptions about the TLS protocol.

As an application of stealth key exchange we discuss sanitizable channel protocols, where a designated party can partly access and modify payload data in a channel protocol. This may be, for instance, an intrusion detection system monitoring the incoming traffic for malicious content and putting suspicious parts in quarantine. The noteworthy feature, inherited from the stealth key exchange part, is that the sender and receiver can use the extra key to still communicate securely and covertly within the sanitizable channel, e.g., by pre-encrypting confidential parts and making only dedicated parts available to the sanitizer. We discuss how such sanitizable channels can be implemented with authenticated encryption schemes like GCM or ChaChaPoly. In combination with our stealth key exchange protocol, we thus derive a full-fledged sanitizable connection protocol, including key establishment, which perfectly complies with regular TLS 1.3 traffic on the network level. We also assess the potential effectiveness of the approach for the intrusion detection system Snort.

Divisions: 20 Department of Computer Science
20 Department of Computer Science > Cryptography and Complexity Theory
DFG-Collaborative Research Centres (incl. Transregio)
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres
Profile Areas
Profile Areas > Cybersecurity (CYSEC)
Forschungsfelder
Forschungsfelder > Information and Intelligence
Forschungsfelder > Information and Intelligence > Cybersecurity & Privacy
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 1119: CROSSING – Cryptography-Based Security Solutions: Enabling Trust in New and Next Generation Computing Environments
Date Deposited: 11 Apr 2024 12:26
Last Modified: 16 Jul 2024 09:07
PPN: 519936582
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