Sepal (software)

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Sepal (чашелистник) refers to a decryption software of the Russian foreign intelligence service SWR . SWR agents use the software to receive and decipher messages sent via shortwave radio. The existence of this software and the “Parabola” program became publicly known through the unmasking of two SWR agents in Germany.

Exposure

The two SWR agents Sascha (code name “Pit”) and Olja (“Tina”) were arrested by the Federal Criminal Police Office in 2012 after the Federal Office for the Protection of the Constitution received a tip from a foreign intelligence service in August 2011 . In 2013 they had to answer before the Stuttgart Higher Regional Court on suspicion of being an agent of the secret service. Both were sentenced to several years' imprisonment, with the woman released from prison in November 2014 and the man released in June 2015 and deported to Russia . They had already been smuggled into the Federal Republic by the SWR predecessor, the KGB, before German reunification , where they built a legend under the aliases Andreas and Heidrunschlag and led a normal family life. For years you have been using the duplex communication method of the Russian secret service, which also includes sepal. The pair of agents were trained in communication technology in a course in Saint Petersburg .

Internet communication is still noticeable. In parallel to the sepal and parabola, the two agents also communicated via the video platform YouTube : There they wrote comments with hidden messages.

According to media reports, the NSA had managed to crack parts of the communication between the Marburg pair of agents and the Moscow SWR headquarters. However, it did not make it clear whether it was radio or Internet communication.

function

Sepal is part of the duplex communication process that SWR uses to keep in touch with its employees abroad. As could be determined on the basis of the seized technology, the communication technology works as follows:

  1. Encrypted text messages for agents in Europe are broadcast as tone sequences via a shortwave transmitter (probably a radio transmitter) ( number transmitter ). Tone sequences are transmitted on changing frequencies between 3 and 30 MHz using the AM modulation method .
  2. Due to the broadcasts in the regular AM mode, the tone sequences can be received by any shortwave receiver. The agents connect the audio output of their receiver to the sound card of their laptop. Sepal compares three received tone sequences to correct transmission errors. In a further step, the sepal translates the tone sequences into columns of numbers and decrypts them into plain text.
  3. In plain text, possible transmission errors still have to be corrected manually.
  4. The answer is sent via satellite. The agents' messages are encrypted with the “Parabola” program. These then send their messages directly to an SWR satellite using a transmitter and a parabolic antenna. This requires a line of sight to the satellite in the time window of the overflight. The technology is comparable to an Inmarsat satellite telephone. The radio link makes it very difficult for ground-based SIGINT devices to detect the signal .
  5. The recorded messages are transmitted to the SWR headquarters via satellite.

Individual evidence

  1. ^ A b Uwe Müller, Lars-Marten Nagel: Russian espionage: agent thriller of historical dimension. In: welt.de . October 21, 2012, accessed October 7, 2018 .
  2. ↑ Despite imprisonment in Germany: Russian top agent expelled , Südwestrundfunk , from November 22, 2014, accessed on November 22, 2014
  3. ↑ Russian spy deported home from Hesse
  4. ↑ Der Spiegel, 27/2013 In the land of the enemy. Pp. 28-30