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.Ifyou knew the initial setting of the machine you could set upyour machine in the same way, type in the encrypted message,and the decrypted letters would flash on the lampboard.If youdidn t have the initial settings (which were determined by top-secret, heavily guarded code books), you would have to workthrough more than ten thousand trillion possible combina-tions of the scrambling system to decrypt the message, evenassuming you knew the exact structure of the machine.Youwould then have to repeat this effort for each new message youwanted to decipher.After World War I it emerged that the Allies had enjoyedconsiderable success in breaking German codes and readingtheir radio traffic.The German military were horrified and in1925 held an enquiry into how to avoid the mistakes of thepast and improve their cryptography.Scherbius device wasselected as the best option, and over the next few years hiscompany, Scherbius and Ritter, supplied over 30,000 Enigmamachines to the German government.Allied cryptanalysts,listening in to German diplomatic and military radio traffic,noticed the difference almost immediately.In 1926 they beganto intercept radio messages that could not be deciphered, andsoon they were forced to admit defeat.The Germans had thebest system of cryptography in the world.German radio secu-rity was complete, their codes unbreakable.As war loomed,the Allies realised they were in trouble.Fortunately both the French and Polish intelligence serviceswere able to make important breakthroughs in the pre-waryears.The first chink in Enigma s armour was provided by aGerman informant, Hans-Thilo Schmidt, in 1931.A disaffectedclerk at cryptography headquarters in Berlin, Schmidt was cul-tivated by a French secret service agent who paid him a heftysum in return for a look at documents explaining the con-struction of the Enigma machine.Using the agent s microfilm107 Secret History Book 23/9/04 4:08 pm Page 108S ECRET H I STORYof the documents, it should have been possible for the Frenchto construct their own Enigma, but this was only a first step.Somehow a cryptanalyst would need to work out the initialsettings used to encrypt any Enigma message, and the Frenchcryptanalysis service declared this to be impossible.The Polish intelligence service refused to admit defeat.Under a post-war agreement they and the French shared intel-ligence, and the French were happy to turn over their findingson Enigma, which the Poles used to build an Enigma replica.Using the replica machine as a starting point, a brilliant youngmathematician named Marian Rejewski pulled off the intellec-tual tour de force necessary to break the Enigma codes.Themain weakness in any system of cryptography is repetition some elements of messages are invariably repeated.TheEnigma machine was supposed to account for this flaw, butRejewski, through a combination of genius and hard work, wasable to discover a way of spotting repetitions in an encodedmessage, and use these to work out the initial settings of themachine that had sent it.From there he could decrypt the mes-sages it generated.Rejewski and his team constructed modifiedversions of the Enigma machines that they called bombes, pos-sibly because of the clicking noise generated by the internalswitches.These functioned as primitive computers and speed-ed up the process of decryption.By 1934 the Poles were reading all German radio traffic, butover the years the machines received upgrades, such as extrascrambler wheels that exponentially increased the number ofpossible settings a cryptanalyst had to work through, and theGermans began to use a new cipher every day.Rejewski didn thave the resources necessary to crack the new, tougher codes,and just when they needed it most the Poles lost the ability toread German signals.Given the increasing anti-Polish rhetoriccoming from the Nazis, it was just a matter of time before theyinvaded.Desperate to preserve the fruits of their labours,Polish intelligence presented two replica Enigmas and the108 Secret History Book 23/9/04 4:08 pm Page 109T HE W ORLD OF E SPI ONAGEplans for the bombes to British intelligence, who managed tosmuggle them out of Poland just two weeks before theGermans marched in.Now the baton passed to British intelligence, who were in theprocess of revamping their codebreaking apparatus.A neworganisation was formed, and based at a Victorian manor housecalled Bletchley Park.It was to be called the Government Codeand Cypher School (GC&CS, often referred to as the Golf,Cheese and Chess Society ), or, according to its official designa-tion, Station X.The motley crew recruited to work at BletchleyPark have since become legendary figures in the secret historyof World War II.They included some of the brightest and mosteccentric men and women in Britain, such as Alan Turing, thegenius considered the father of the modern computer, and IanFleming, creator of James Bond [ Pobierz całość w formacie PDF ]
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.Ifyou knew the initial setting of the machine you could set upyour machine in the same way, type in the encrypted message,and the decrypted letters would flash on the lampboard.If youdidn t have the initial settings (which were determined by top-secret, heavily guarded code books), you would have to workthrough more than ten thousand trillion possible combina-tions of the scrambling system to decrypt the message, evenassuming you knew the exact structure of the machine.Youwould then have to repeat this effort for each new message youwanted to decipher.After World War I it emerged that the Allies had enjoyedconsiderable success in breaking German codes and readingtheir radio traffic.The German military were horrified and in1925 held an enquiry into how to avoid the mistakes of thepast and improve their cryptography.Scherbius device wasselected as the best option, and over the next few years hiscompany, Scherbius and Ritter, supplied over 30,000 Enigmamachines to the German government.Allied cryptanalysts,listening in to German diplomatic and military radio traffic,noticed the difference almost immediately.In 1926 they beganto intercept radio messages that could not be deciphered, andsoon they were forced to admit defeat.The Germans had thebest system of cryptography in the world.German radio secu-rity was complete, their codes unbreakable.As war loomed,the Allies realised they were in trouble.Fortunately both the French and Polish intelligence serviceswere able to make important breakthroughs in the pre-waryears.The first chink in Enigma s armour was provided by aGerman informant, Hans-Thilo Schmidt, in 1931.A disaffectedclerk at cryptography headquarters in Berlin, Schmidt was cul-tivated by a French secret service agent who paid him a heftysum in return for a look at documents explaining the con-struction of the Enigma machine.Using the agent s microfilm107 Secret History Book 23/9/04 4:08 pm Page 108S ECRET H I STORYof the documents, it should have been possible for the Frenchto construct their own Enigma, but this was only a first step.Somehow a cryptanalyst would need to work out the initialsettings used to encrypt any Enigma message, and the Frenchcryptanalysis service declared this to be impossible.The Polish intelligence service refused to admit defeat.Under a post-war agreement they and the French shared intel-ligence, and the French were happy to turn over their findingson Enigma, which the Poles used to build an Enigma replica.Using the replica machine as a starting point, a brilliant youngmathematician named Marian Rejewski pulled off the intellec-tual tour de force necessary to break the Enigma codes.Themain weakness in any system of cryptography is repetition some elements of messages are invariably repeated.TheEnigma machine was supposed to account for this flaw, butRejewski, through a combination of genius and hard work, wasable to discover a way of spotting repetitions in an encodedmessage, and use these to work out the initial settings of themachine that had sent it.From there he could decrypt the mes-sages it generated.Rejewski and his team constructed modifiedversions of the Enigma machines that they called bombes, pos-sibly because of the clicking noise generated by the internalswitches.These functioned as primitive computers and speed-ed up the process of decryption.By 1934 the Poles were reading all German radio traffic, butover the years the machines received upgrades, such as extrascrambler wheels that exponentially increased the number ofpossible settings a cryptanalyst had to work through, and theGermans began to use a new cipher every day.Rejewski didn thave the resources necessary to crack the new, tougher codes,and just when they needed it most the Poles lost the ability toread German signals.Given the increasing anti-Polish rhetoriccoming from the Nazis, it was just a matter of time before theyinvaded.Desperate to preserve the fruits of their labours,Polish intelligence presented two replica Enigmas and the108 Secret History Book 23/9/04 4:08 pm Page 109T HE W ORLD OF E SPI ONAGEplans for the bombes to British intelligence, who managed tosmuggle them out of Poland just two weeks before theGermans marched in.Now the baton passed to British intelligence, who were in theprocess of revamping their codebreaking apparatus.A neworganisation was formed, and based at a Victorian manor housecalled Bletchley Park.It was to be called the Government Codeand Cypher School (GC&CS, often referred to as the Golf,Cheese and Chess Society ), or, according to its official designa-tion, Station X.The motley crew recruited to work at BletchleyPark have since become legendary figures in the secret historyof World War II.They included some of the brightest and mosteccentric men and women in Britain, such as Alan Turing, thegenius considered the father of the modern computer, and IanFleming, creator of James Bond [ Pobierz całość w formacie PDF ]