“Phonotactic Reconstruction of Encrypted VoIP Conversations: Hookt on Fon-Iks”, Andrew M. White, Austin R. Matthews, Kevin Z. Snow, Fabian Monrose2011-05-22 (compressed Transformers, computer security)⁠:

In this work, we unveil new privacy threats against Voice-over-IP (VoIP) communications. Although prior work has shown that the interaction of variable bit-rate codecs and length-preserving stream ciphers leaks information, we show that the threat is more serious than previously thought.

In particular, we derive approximate transcripts of encrypted VoIP conversations by segmenting an observed packet stream into subsequences representing individual phonemes and classifying those subsequences by the phonemes they encode.

Drawing on insights from the computational linguistics and speech recognition communities, we apply novel techniques for unmasking parts of the conversation.

We believe our ability to do so underscores the importance of designing secure (yet efficient) ways to protect the confidentiality of VoIP conversations.

See Also:

• Spot Me if You Can: Uncovering Spoken Phrases in Encrypted VoIP Conversations

• Hearing your touch: A new acoustic side channel on smartphones

• Listen to Your Key: Towards Acoustics-based Physical Key Inference

• Hard Drive of Hearing: Disks that Eavesdrop with a Synthesized Microphone

• Lamphone: Real-Time Passive Sound Recovery from Light Bulb Vibrations

• Real-time Synthesis of Imagined Speech Processes from Minimally Invasive Recordings of Neural Activity

• Semantic reconstruction of continuous language from non-invasive brain recordings