Random numbers, Persian code: A mysterious signal transfixes radio sleuths

Original Article ↗ Hacker News Discussion ↗

Alternative sources & background

  • Several commenters prefer the RFE/RL article over the Wired piece, citing trust concerns with the latter.
  • The linked Priyom.org analysis is highlighted as a detailed technical and attribution deep-dive on the station (V32).

Why shortwave numbers stations?

  • Argued advantages:
    • Simple, robust, and cheap; small shortwave receivers are common enough (“world band radios,” ham gear).
    • Broadcast is one-to-many and inherently anonymous: you can’t easily tell who is listening.
    • One-time pads (OTP) remain information-theoretically secure if used correctly and distributed offline.
  • Alternatives debated:
    • Phones/satellite: seen as more traceable and attackable, though some argue satellite downlinks are also broad and receivers can’t easily be located.
    • Internet steganography and covert web channels are mentioned, but depend on functioning connectivity, which may be absent in war/blackout conditions.

Receiver hardware availability

  • Some say shortwave-capable radios are niche in the US; others say they’re still readily available as “world radios.”
  • Ham handhelds are mentioned but clarified as typically VHF/UHF-only, not shortwave.

Triangulation & propagation challenges

  • Direction-finding HF sources is portrayed as non-trivial:
    • Ionospheric reflections, skip zones, multipath, and terrain complicate locating the true source.
    • Highly directional antennas at HF must be large and are hard to move; precise long-range triangulation requires expensive distributed arrays.
  • Others note ham “fox hunts” as evidence that locating transmitters is possible, but concede HF is harder than VHF/UHF.
  • Consensus: local search is easy; long-range precision is difficult.

Location, attribution & possible intent

  • Multiple posts claim the transmitter is at a shortwave facility on a US military base near Böblingen/Stuttgart, Germany, with coordinates supplied and map imagery discussed.
  • Priyom’s writeup is cited suggesting a likely CIA-operated station targeting Iran, possibly as a last-resort channel for assets during an Internet blackout.
  • Alternative interpretations:
    • Psychological operation to make Iranian authorities suspect internal traitors.
    • A potential decoy to waste foreign SIGINT resources.
    • Some assert numbers stations don’t need hidden locations and can be in defended bases.

Crypto, steganography & history

  • Discussion covers:
    • OTP basics, the danger of ever broadcasting the pad itself, and confusion between OTPs and book ciphers.
    • Ideas for pseudo-OTP using books, irrational numbers, or arbitrary data, with warnings about statistical attacks.
    • Historical use of BBC “personal messages” and code phrases in WWII and the 1953 Iran coup.
    • Steganographic techniques in regular broadcasts (PSK on carrier, RDS manipulation) as theoretical alternatives.

Culture & side notes

  • The Conet Project is mentioned as a canonical collection of numbers station recordings.
  • There is meta-discussion of nominative determinism around cryptography-related surnames, and light joking around fox-hunting, AM radios, and conspiracy fodder.