Data security plays a crucial role in all areas of data transmission, processing, and storage. This paper considers security in eavesdropping attacks over wireless communication links in aeronautical telemetry systems. Data streams in these systems are often encrypted by traditional encryption algorithms such as the Advanced Encryption Standard (AES). Here, we propose a secure coding technique for the integrated Network Enhanced Telemetry (iNET) communications system that can be coupled with modern encryption schemes. We consider a wiretap scenario where there are two telemetry links between a test article (TA) and a legitimate receiver, or ground station (GS). We show how these two links can be used to transmit both encrypted and unencrypted data streams while keeping both streams secure. A single eavesdropper is assumed who can tap into both links through its noisy channel. Since our scheme does not require encryption of the unencrypted data stream, the proposed scheme offers the ability to reduce the size of the required secret key while keeping the transmitted data secure.
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Whisper: a unilateral defense against VoIP traffic re-identification attacks
Encrypted voice-over-IP (VoIP) communication often uses variable bit rate (VBR) codecs to achieve good audio quality while minimizing bandwidth costs. Prior work has shown that encrypted VBR-based VoIP streams are vulnerable to re-identification attacks in which an attacker can infer attributes (e.g., the language being spoken, the identities of the speakers, and key phrases) about the underlying audio by analyzing the distribution of packet sizes. Existing defenses require the participation of both the sender and receiver to secure their VoIP communications.
This paper presents Whisper, the first unilateral defense against re-identification attacks on encrypted VoIP streams. Whisper works by modifying the audio signal before it is encoded by the VBR codec, adding inaudible audio that either falls outside the fixed range of human hearing or is within the human audible range but is nearly imperceptible due to its low amplitude. By carefully inserting such noise, Whisper modifies the audio stream's distribution of packet sizes, significantly decreasing the accuracy of re-identification attacks. Its use is imperceptible by the (human) receiver.
Whisper can be instrumented as an audio driver and requires no changes to existing (potentially closed-source) VoIP software. Since it is a unilateral defense, it can be applied at will by a user to enhance the privacy of its voice communications. We demonstrate that Whisper significantly reduces the accuracy of re-identification attacks and incurs only a small degradation in audio quality.
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- Award ID(s):
- 1718498
- NSF-PAR ID:
- 10178638
- Date Published:
- Journal Name:
- Proceedings of the Annual Computer Security Applications Conference (ACSAC)
- Page Range / eLocation ID:
- 286 to 296
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1145/3359789.3359807
