The SIGABA or Converter M-134 is a cryptography machine which worked by means of rotors which were used to encrypt messages and is similar to the enigma as it used rotors to encrypt the plain text to characters of the cipher text. It used 15 of such rotors.
The SIGABA as a cryptography machine was far more efficient and far more difficult to crack when compared to the enigma. Its encryption efficiency which prevented crackers from cracking its ciphers was its only raison d'etre. However good the SIGABA was at encryption, it was always not as preferred as the enigma due to the fact that it was large, expensive, difficult to operate and fragile.
The SIGABA however was used in many situations in spite of its short comings. However it was a more of a bane than a boon in most cases and especially not useful in tactical communications due to the same afore mentioned reasons. Therefore, the enigma was always preferred over the SIGABA in most cases. The only reason the SIGABA was able to produce relatively better and harder to crack encryptions was because it could advanced its main rotors in a complex pseudorandom fashion. In spite of this, its shortcomings far out weighed its benefits and hence the enigma was the Crypto Machine of choice.
- The ECM Mark II, also known as SIGABA, M-134-C, and CSP-889
- ECM Mark II or SIGABA machine
- Image source (public domain image)
- Image published with permission from Prof. Gessler