[cryptography] JackPair Voice Encryption Dongle

Tom Ritter tom at ritter.vg
Mon Aug 18 09:58:38 EDT 2014


DH with a 'Pairing Code' (ala ZRTP) to prevent MITM. Light on exact
details, but they say it will be open source.

"we think 10-12 digits [for a pairing code] is probably good enough,
and more friendly for human reading"

"We are using Diffie-Hellman at this point, and working on Elliptic
curve Diffie-Hellman."

"Synchronous stream cipher is used, with XOR'ed key-stream resulted
from pseudo random number generator using OTSK as seed, and periodic
marker flag for re-synchronization."

"JackPair uses audio codec from Codec2, which has reasonable good
sound quality at 1.2kbps. We have tested JackPair on top of GSM AMR
4.75 (Adaptive Multi-Rate, 4.75kbps) and HR (Half-Rate, 6.5kbps)."

"Unlike traditional fax-modem technologies, our modem is designed from
scratch to fight off the optimization done by GSM codec, including
memory-less codec, voice activity detection (VAD)., automatic gain
control (AGC) etc.. Basically we have to use synthesized voice to make
mobile phones & media servers believe our signal is human voice, not
just modulated waves."


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