gary
16-07-2013, 11:28 PM
One of the ultra secrets of WWII was the US-built SIGSALY secure speech
communication system, the first of which was set up between Washington and London,
and today marks the 70th anniversary of its inaugural conference call.
Before SIGSALY, a voice scrambler system designated as A-3 had been in use
by the allies, but unbeknowst to them, the Germans has broken it and were even
intercepting traffic between Roosevelt and Churchill.
Technically, SIGSALY was ahead of its time and it helped forge the way for many
communications technologies in common use today. For example, it was the
first system to use quantized speech transmission - that is, converting it to
a digital form. It was the first speech transmission system to use pulse
code modulation (PCM), the first to use multilevel frequency shift keying (FSK)
and the first to use bandwidth compression on speech.
Each SIGSALY terminal consisted of 40 racks of equipment weighing 50 tons
and the voice data was encrypted by using one-time pads, the source of which
were phonographic records with soundtracks consisting of random thermal
noise. To decrypt the signal in real-time, an identical one-time pad record
had to be played in synchrony with that at the source. The records were used
once and then destroyed. This therefore required the secure manufacturing and
distribution of the one-time pad encryption key records to terminal locations
around the world, it in itself quite a logistical feat.
The system was nicknamed "the Green Hornet" owing to the buzzing sound
one would hear if you attempted to eavesdrop on a transmission.
The Germans never managed to crack SIGSALY transmissions.
Developed at Bell Labs, the SIGSALY development was assisted by none other than
the British mathematical genius Alan Turing.
A SIGSALY terminal was installed in the AMP Building in Queen Street in
Brisbane and was used by MacArthur and his staff. Later, that system was
put aboard a ship and accompanied MacArthur as the Americans island-hopped
through the Pacific.
Interested readers can learn more about this fascinating WWII technology from
this 9 minute AT&T video -
http://www.youtube.com/watch?v=Ev1Mc_rOM74
or by reading this National Security Agency (NSA) history web site page -
http://www.nsa.gov/about/cryptologic_heritage/center_crypt_history/publications/sigsaly_story.shtml#2
communication system, the first of which was set up between Washington and London,
and today marks the 70th anniversary of its inaugural conference call.
Before SIGSALY, a voice scrambler system designated as A-3 had been in use
by the allies, but unbeknowst to them, the Germans has broken it and were even
intercepting traffic between Roosevelt and Churchill.
Technically, SIGSALY was ahead of its time and it helped forge the way for many
communications technologies in common use today. For example, it was the
first system to use quantized speech transmission - that is, converting it to
a digital form. It was the first speech transmission system to use pulse
code modulation (PCM), the first to use multilevel frequency shift keying (FSK)
and the first to use bandwidth compression on speech.
Each SIGSALY terminal consisted of 40 racks of equipment weighing 50 tons
and the voice data was encrypted by using one-time pads, the source of which
were phonographic records with soundtracks consisting of random thermal
noise. To decrypt the signal in real-time, an identical one-time pad record
had to be played in synchrony with that at the source. The records were used
once and then destroyed. This therefore required the secure manufacturing and
distribution of the one-time pad encryption key records to terminal locations
around the world, it in itself quite a logistical feat.
The system was nicknamed "the Green Hornet" owing to the buzzing sound
one would hear if you attempted to eavesdrop on a transmission.
The Germans never managed to crack SIGSALY transmissions.
Developed at Bell Labs, the SIGSALY development was assisted by none other than
the British mathematical genius Alan Turing.
A SIGSALY terminal was installed in the AMP Building in Queen Street in
Brisbane and was used by MacArthur and his staff. Later, that system was
put aboard a ship and accompanied MacArthur as the Americans island-hopped
through the Pacific.
Interested readers can learn more about this fascinating WWII technology from
this 9 minute AT&T video -
http://www.youtube.com/watch?v=Ev1Mc_rOM74
or by reading this National Security Agency (NSA) history web site page -
http://www.nsa.gov/about/cryptologic_heritage/center_crypt_history/publications/sigsaly_story.shtml#2