Sigtot

The punched tape reader, like this one on display in the US National Cryptological Museum , was part of the encryption system.

Sigtot ( own spelling : SIGTOT ), later also referred to as SSM-33 , was an American cipher machine developed and used during the Second World War . For encryption , she used the cryptographically secure one-time key method ( English One-Time Pad , or OTP for short ).

history

The mixer of type 131B2 was the heart of the system.

The one-time key procedure was proposed as early as the 19th century by the American cryptologist Frank Miller (1842–1925). It has been used from that time to the present day. It is characterized by its fundamental simplicity and, if used correctly, as the American scientist Claude Shannon (1916–2001) showed in the 1940s, it is demonstrably safe and cannot be broken . The armed forces of the United States also relied on this process during the Second World War and implemented it in the form of a punched  tape reader (picture above) combined with a mixer of the type 131B2  (picture right) . Sigtot was used with minor modifications until the mid-1950s. Some copies remained in use until around 1960.

The British allies used a machine based on the same principle called the 5-UCO .

literature

• Stephen J. Kelley: The SIGCUM Story - Cryptographic Failure, Cryptographic Success. Cryptologia 1997, 21: 4, pp. 289-316, doi: 10.1080 / 0161-119791885940
• National Security Agency : A History of US Communications Security. Fort George G. Meade 1973, PDF; 11.5 MB (English)

Web links

Commons : SIGTOT  - collection of images, videos and audio files

• SIGTOT in the Crypto Museum on CryptoMuseum.com (English)
• SSM-33 (SIGTOT) Cryptosystem on JProc.ca (English)
• Circuit diagram at JProc.ca (English)

Individual evidence

1. ↑ SSM-33 (SIGTOT) Cryptosystem on JProc.ca (English), accessed on August 9, 2019.
2. ^ Steven M. Bellovin: Frank Miller: Inventor of the One-Time Pad. In: Cryptologia. Vol. 35, Issue 3, Rose-Hulman Institute of Technology. Taylor & Francis, Philadelphia, Pennsylvania January 3, 2011, ISSN  0161-1194 , pp. 203-22, online at Columbia.edu, accessed August 9, 2019. PDF; 2.4 MB .
3. ↑ Claude Shannon: Communication Theory of Secrecy Systems (PDF; 563 kB). Bell System Technical Journal, Vol. 28, 1949 (October), pp. 656-715.
4. ^ National Security Agency: A History of US Communications Security. Fort George G. Meade 1973, PDF; 11.5 MB (English), p. 90, accessed on August 9, 2019.
5. ^ National Security Agency: A History of US Communications Security. Fort George G. Meade 1973, PDF; 11.5 MB (English), p. 42, accessed on August 9, 2019.
6. ↑ Ralph Erskine: The 1944 Naval BRUSA Agreement and its Aftermath , Cryptologia, 30: 1, 2006, pp. 1–22, doi : 10.1080 / 01611190500401086