Le Sphinx. Controls. 1 sur 5 17/04/ :59. Pocket cipher device

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1 1 sur 5 17/04/ :59 Le Sphinx Pocket cipher device Homepage Crypto Index Glossary Enigma Hagelin Fialka Siemens Philips Nema Racal Motorola STK Transvertex Gretag OMI HELL Telsy Teltron TST Mils AT&T Tadiran USA USSR UK Yugoslavia Voice Hand OTP LE SPHINX 1 was a pocket cryptographic device, developed around 1930 by Société des Codes Télégraphiques Georges Lugagne in Paris (France). The device consists of 10 sliding bars with two scrambled alphabets each, and should therefore be classed as an alphabet transposition cipher. At the time, it was advertised as a method for secret writing when sending (radio) telegrams. The device consists of a metal frame with ten lanes, each of which holds two movable rods with scrambled alphabets. The 20 transposed alphabets are identified by a number, imprinted in red, and are always used in pairs, with the upper alphabet representing the clear text and the lower alphabet used for the cipher text. 2 The rods can be moved by treaded knobs at the right side which engage gears at the bottom. Two fixed ruler windows are present for setting and reading the plain text and cipher text. The source text is processed 10 characters at a time. The device is based on the 1912 invention of a mechanical pocket transposition cipher device by Georges Lugagne of Boches-du-Rhône (near Marseille, France), which was registered in 1913 as French Patent [1]. Around the same time, the device was patented in the United Kingdom as British patent 23,204 [2]. The device was marketed in France by Lugagne's companies in Paris and Marseille, who had become known for their international telegraphic code books of The image on the right shows the original design of 1912, which is mechanically less complex, but works very similar. It also consists of 20 paired scrambled alphabets, but they are not linked mechanically. The sliding rods are made of ivory. In 1931, the design was improved by Lugagne's employee Paul Godillon, who added the gears and the 10 treaded knobs at the right hand side. He was also responsible for adding the S-shaped gaps at each end of the alphabet rods, allowing the scrambled alphabets to be coupled in pairs. His invention was patented in France on 4 Feb [3]. The same patent was filed in the US on 1 December 1931 by Albert Gentet [4], who also added the movable index to each window [5]. It is currently unclear where Le Sphinx was manufactured and by whom, but it is possible that it was made by the famous slide rule manufacturer BARBOTHEU in Paris, who also manufactured the 1912 version [7]. The original Transpositeur is further described in an article by Daniel Tant [8]. 1. 'Le Sphinx' is French for 'The Sphinx'. Also see the discussion about the name. 2. This is just an assumption. There is no reason why it could not be used the other way around, as long as both parties do it in the same way. Mixers Phones FILL Codebooks Spy radio Burst encoders Intercept Covert Controls The diagram below gives an overview of the various features of Le Sphinx. The device measures just 162 x 87 x 20 mm and consist of a die-cast metal alloy frame with 10 cogwheel driven lanes, each of which accomodates two physically locked scrambled alphabets. This effectively results in 10 different transposition ciphers that allow the text to be enciphered in groups of 10 letters.

2 2 sur 5 17/04/ :59 Radio PC Telex People Agencies Manufacturers Donate Kits Shop News Events Wanted Contact About Links On top of the device are two horizontal windows: one for the plaintext and one for the ciphertext. The position of the rods or rulers with the alphabets can be altered by means of 10 treaded knobs at the right side. Each knob drives a cogwheel that in turn engages the teeth at the bottom of a rod. Each position has a 'click' to ensure that the letters are properly shown in the windows. Name Le Sphinx The pocket cryptographic device featured on this page, was marketed by Société des Codes Télégraphiques Georges Lugagne, which had offices in Paris and Marseille (France). It is currently unclear under what name the device was sold, but since the bakelite storage case holds a raised image of a sphinx, it is commonly referred to as SPHINX. The metal label at the left side of the device shows the company name and the image of the sphinx, with the text 'LE SPHINX' (the sphinx). In order to distinguish it from the Sphinx Cipher Machine, we will call it 'Le Sphinx'. The name 'Sphinx' originates from the Greek language and represents a mythical creature that generally consists of the body of a lion with the head of a human. In Greek tradition it may also have the wings of a bird. Sphinx' also exist in Egyptian culture (e.g. Great Sphinx of Giza) [9]. Permutations When calculating the total number of combinations that can be made with the device, we will first look at the original design of It had 20 alphabet rulers, 10 of which were intended as the upper alphabets and the other 10 were the lower alphabets [1]. This gives us 10! (or 3,628,800) possible combinations of alphabets 1 for the upper half only. As the same is true for the lower half, the total number of combinations would be 3,628,800 x 3,628,800, which is no less than: 13,168,189,440,000 After the design had been improved by Paul Godillon in 1931, there was no longer a differece between the upper and the lower alphabets, allowing them to be mixed freely [3]. As a result the total number of combinations in which the 20 alphabets can be mixed, increased to 20! or: 2,432,902,008,176,640,000

3 3 sur 5 17/04/ : ! is the mathematical notation for 10 x 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1 Operation Before exchanging a message by means of Le Sphinx, both parties first have to agree which alphabet is used in each position. This is done by quoting the red number that is printed on the top of each rod. This is known as the settings or the key and is usually pre-arranged between the parties. For the default position, which we have used on this page, the key would be: Both users should now install the alphabets in the order indicated on the key sheet. Each pair (e.g ) should be coupled by fitting the S-shaped gap at the top of the lower alphabet into the S-shaped gap at the bottom of the upper alphabet. For the above key, the setup would be: Le Sphinx is constructed in such a way that the user can move the rulers by means of treaded knobs at the right side. There are 5 sets of two knobs. The leftmost knobs (i.e. the larger ones) are used to control the rightmost 5 lanes, whilst the rightmost knobs control the leftmost 5 lanes. Furthermore, there are two windows through which we can read a row of letters. Now rotate the knobs so that the first 10 letters of the plaintext are visible in the upper window, for example: TOPSECRETS All you now have to do is read the ciphertext from the lower window, which in this case is: IRUVPYQHWB All the receiving party has to do, is rotate the rulers so that the ciphertext is visible in the lower window. The original plaintext can now be read from the upper window.

4 4 sur 5 17/04/ :59 Cipher security Despite the large number of possible arrangements of the alphabets, Le Sphinx provides only low-grade cipher security. This is mainly caused by the fact that the arrangment of the alphabets does not change during the course of a message. If a message is long enough, it can be solved by frequency analysis. For very short messages, the cipher would be relatively secure though. Another weakness of the system is that there is no provision to send the key at the start of a message. Instead, it has to be pre-arranged. This was also the case with the German Enigma cipher machine, although in that case, procedures were in place to add a random message key. Alphabets The table below shows each of the 20 scrambled alphabets of our device. Note that the alphabets are printed in the regular order, but that they are shifted by a few positions on each ruler. Also note that the alphabets on the first 10 rulers (1-10) are in ascending order, whilst the alphabets on the last 10 rulers (11-20) are in descending order. 1 ABCDEFGHIJKLMNOPQRSTUVWXYZ 2 CDEFGHIJKLMNOPQRSTUVWXYZAB 3 EFGHIJKLMNOPQRSTUVWXYZABCD 4 GHIJKLMNOPQRSTUVWXYZABCDEF 5 IJKLMNOPQRSTUVWXYZABCDEFGH 6 MNOPQRSTUVWXYZABCDEFGHIJKL 7 PQRSTUVWXYZABCDEFGHIJKLMNO 8 RSTUVWXYZABCDEFGHIJKLMNOPQ 9 TUVWXYZABCDEFGHIJKLMNOPQRS 10 VWXYZABCDEFGHIJKLMNOPQRSTU 11 BAZYXWVUTSRQPONMLKJIHGFEDC 12 DCBAZYXWVUTSRQPONMLKJIHGFE 13 FEDCBAZYXWVUTSRQPONMLKJIHG 14 HGFEDCBAZYXWVUTSRQPONMLKJI 15 LKJIHGFEDCBAZYXWVUTSRQPONM 16 ONMLKJIHGFEDCBAZYXWVUTSRQP 17 SRQPONMLKJIHGFEDCBAZYXWVUT 18 UTSRQPONMLKJIHGFEDCBAZYXWV 19 WVUTSRQPONMLKJIHGFEDCBAZYX 20 YXWVUTSRQPONMLKJIHGFEDCBAZ References 1. Georges Lugagne, French Patent Filed 24 October 1913, granted 23 December Priority date 23 October George Lugagne, British Patent 23,204 Filed 14 October 1913, granted 9 April Paul Godillon, French Patent 710,604 Filed 4 February 1931, granted 27 August 1931.] 4. Albert Gentet, US Patent 1,956,384 Filed 1 December 1931, granted 24 April Albert Gentet, French patent Filed 1 February 1937, granted 11 May Pendergrass to Friedman, Classified files of US Patent Office US Government Internal Memorandum, 8 October pp Linialis, Règles Rares ou Originales Website Linealis.org. Retrieved April Daniel Tant, Le transpositeur à permutations secrètes Date unknown. Retrieved April 2016 (French) Wikipedia, Sphinx 1

5 5 sur 5 17/04/ :59 Retrieved April Approved for release by NSA on 16 July 2014, E.O Reproduced here by kind permission of the president of the Association des Réservistes du Chiffre et de la Sécurité de l'information. Further information Le Sphinx on Jerry Proc's crypto pages Other Lugagne cipher systems Other manual cipher methods Other cipher systems Any links shown in red are currently unavailable. If you like the information on this website, why not make a donation? Crypto Museum. Created: Friday 15 April Last changed: Friday, 15 April :04 CET.