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| Link | Quote | Stars | Tags | Author |
| 307eed7 | que p | Simon Singh | ||
| 31a5fc1 | One of the features of the Enigma machine was its inability to encipher a letter as itself, which was a consequence of the reflector. The letter a could never be enciphered as A, the letter b could never be enciphered as B, and so on. | Simon Singh | ||
| fb10039 | Turing needed more staff, but his requests had been blocked by Commander Edward Travis, who had taken over as Director of Bletchley, and who felt that he could not justify recruiting more people. On October 21, 1941, the cryptanalysts took the insubordinate step of ignoring Travis and writing directly to Churchill. | Simon Singh | ||
| 50b95de | war, instead of finishing in 1945, would have ended in 1948 had the Government Code and Cypher School not been able to read the Enigma cyphers and produce the Ultra intelligence." During this period of delay, additional lives would have been lost in Europe, and Hitler would have been able to make greater use of his V-weapons, inflicting damage throughout southern England. The historian David Kahn summarizes the impact of breaking Enigma: "I.. | Simon Singh | ||
| f183060 | Even the Vatican, probably the second most active center of cryptanalysis, would send Soro seemingly impenetrable messages that had fallen into its hands. In 1526, Pope Clement VII sent him two encrypted messages, and both were returned having been successfully cryptanalyzed. | Simon Singh | ||
| afa9e87 | imagined a machine whose internal workings could be altered so that it could perform all the functions of all conceivable Turing machines. The alterations would be made by inserting carefully selected tapes, which transformed the single flexible machine into a dividing machine, a multiplying machine, or any other type of machine. Turing called this hypothetical device a universal Turing machine because it would be capable of answering any q.. | Simon Singh | ||
| a8b84f3 | Turing knew of Babbage's work, and the universal Turing machine can be seen as a reincarnation of Difference Engine No. 2. In fact, Turing had gone much further, and provided computing with a solid theoretical basis, | Simon Singh | ||
| 2ad6c5f | A large amount of identically encrypted material provides a cryptanalyst with a correspondingly larger chance of identifying the key. | Simon Singh | ||
| 679f8e0 | the Germans therefore took the clever step of using the day key settings to transmit a new message key for each message. | Simon Singh | ||
| 1dd7bef | The fundamental weakness of the Vigenere cipher is its cyclical nature. If the keyword is five letters long, then every fifth letter of the plaintext is encrypted according to the same cipher alphabet. If the cryptanalyst can identify the length of the keyword, the ciphertext can be treated as a series of five monoalphabetic ciphers, and each one can be broken by frequency analysis. However, consider what happens as the keyword gets longer... | Simon Singh | ||
| 70840ab | Rejewski had vastly simplified the task of finding the day key by divorcing the problem of finding the scrambler settings from the problem of finding the plugboard settings. On their own, both of these problems were solvable. Originally, we estimated that it would take more than the lifetime of the universe to check every possible Enigma key. However, Rejewski had spent only a year compiling his catalogue of chain lengths, and thereafter he.. | Simon Singh | ||
| e8e5817 | the First World War was the chemists' war, because mustard gas and chlorine were employed for the first time, | Simon Singh | ||
| 97ea716 | Second World War was the physicists' war, because the atom bomb was detonated. | Simon Singh | ||
| 7b6d346 | it can be mathematically proved that it is impossible for a cryptanalyst to crack a message encrypted with a onetime pad cipher. In other words, the onetime pad cipher is not merely believed to be unbreakable, just as the Vigenere cipher was in the nineteenth century, it really is absolutely secure | Simon Singh | ||
| 430c3be | the Third World War would be the mathematicians' war, because mathematicians will have control over the next great weapon of war--information. Mathematicians have been responsible for developing the codes that are currently used to protect military information. | Simon Singh | ||
| ba0308b | The fate of the Polish nation had depended on Rejewski, and he did not disappoint his country. Rejewski's attack on Enigma is one of the truly great accomplishments of cryptanalysis. | Simon Singh | ||
| f76f6ed | it requires a great deal of time, effort and money to create a random key. The best random keys are created by harnessing natural physical processes, such as radioactivity, which is known to exhibit truly random behavior. The cryptographer could place a lump of radioactive material on a bench, and detect its emissions with a Geiger counter. Sometimes the emissions follow each other in rapid succession, sometimes there are long delays--the t.. | Simon Singh | ||
| 1a71040 | Histaiaeus shaved the head of his messenger, wrote the message on his scalp, and then waited for the hair to regrow. This was clearly a period of history that tolerated a certain lack of urgency. | Simon Singh | ||
| 654fa63 | Secret communication achieved by hiding the existence of a message is known as steganography | Simon Singh | ||
| 7b3fc37 | the hotline between the presidents of Russia and America is secured via a onetime pad cipher. | Simon Singh | ||
| ad68d3f | When Hermann Goring visited Warsaw in 1934, he was totally unaware of the fact that his communications were being intercepted and deciphered. As he and other German dignitaries laid a wreath at the Tomb of the Unknown Soldier next to the offices of the Biuro Szyfrow, Rejewski could stare down at them from his window, content in the knowledge that he could read their most secret communications. | Simon Singh | ||
| ecfa2f8 | the enemy of security: repetition leads to patterns, and cryptanalysts thrive on patterns. | Simon Singh | ||
| ec83a01 | By depriving Rejewski of the keys, Langer believed he was preparing him for the inevitable time when the keys would no longer be available. He knew that if war broke out it would be impossible for Schmidt to continue to attend covert meetings, and Rejewski would then be forced to be self-sufficient. Langer thought that Rejewski should practice self-sufficiency in peacetime, as preparation for what lay ahead. | Simon Singh | ||
| 26e46e4 | quantum cryptography is a system that ensures the security of a message by making it hard for Eve to read accurately a communication between Alice and Bob. Furthermore, if Eve tries to eavesdrop then Alice and Bob will be able to detect her presence. Quantum cryptography therefore allows Alice and Bob to exchange and agree upon a onetime pad in complete privacy, and thereafter they can use this as a key to encrypt a message. | Simon Singh | ||
| 596e846 | Babbage's successful cryptanalysis of the Vigenere cipher was probably achieved in 1854, soon after his spat with Thwaites, but his discovery went completely unrecognized because he never published it. The discovery came to light only in the twentieth century, when scholars examined Babbage's extensive notes. In the meantime, his technique was independently discovered by Friedrich Wilhelm Kasiski, a retired officer in the Prussian army. Eve.. | Simon Singh | ||
| e9c24aa | the development of a fully operational quantum computer would imperil our personal privacy, destroy electronic commerce and demolish the concept of national security. A quantum computer would jeopardize the stability of the world. | Simon Singh | ||
| 9298a35 | It is quite possible that British Intelligence demanded that Babbage keep his work secret, thus providing them with a nine-year head start over the rest of the world. | Simon Singh | ||
| 9e42146 | French listening posts learned to recognize a radio operator's fist. Once encrypted, a message is sent in Morse code, as a series of dots and dashes, and each operator can be identified by his pauses, the speed of transmission, and the relative lengths of dots and dashes. A fist is the equivalent of a recognizable style of handwriting. | Simon Singh | ||
| 3933961 | Lyndon Johnson and Richard Nixon were guilty of unjustified wiretaps, and President John F. Kennedy conducted dubious wiretaps in the first month of his presidency. | Simon Singh | ||
| ca3f16c | During a security briefing at the White House, Defense Secretary Donald Rumsfeld breaks some tragic news: "Mr President, three Brazilian soldiers were killed yesterday while supporting U.S. troops." "My God!" shrieks President George W. Bush, and he buries his head in his hands. He remains stunned and silent for a full minute. Eventually, he looks up, takes a deep breath, and asks Rumsfeld: "How many is a brazillion?" | Simon Singh | ||
| 50ee699 | The three Britons had to sit back and watch as their discoveries were rediscovered by Diffie, Hellman, Merkle, Rivest, Shamir and Adleman over the next three years. | Simon Singh | ||
| 176e40d | Chinese wrote messages on fine silk, which was then scrunched into a tiny ball and covered in wax. The messenger would then swallow the ball of wax. | Simon Singh | ||
| a08cf13 | He was a rather quirky worker, and he didn't really fit into the day-to-day business of GCHQ. But in terms of coming up with new ideas he was quite exceptional. You had to sort through some rubbish sometimes, but he was very innovative and always willing to challenge the orthodoxy. | Simon Singh | ||
| cf6eb66 | The first microdot to be spotted by the FBI was in 1941, following a tip-off that the Americans should look for a tiny gleam from the surface of a letter, indicative of smooth film. | Simon Singh | ||
| f72689e | We would be in real trouble if everybody in GCHQ was like him, but we can tolerate a higher proportion of such people than most organizations. We put up with a number of people like him. Figure 66 James Ellis. (photo credit 6.4) One of Ellis's greatest qualities was his breadth of knowledge. | Simon Singh | ||
| db93dd4 | first ever military cryptographic device, the Spartan scytale, dating back to the fifth century B.C. The scytale is a wooden staff around which a strip of leather or parchment is wound, | Simon Singh | ||
| 3d5b34e | The German military were equally unenthusiastic, because they were oblivious to the damage caused by their insecure ciphers during the Great War. For example, they had been led to believe that the Zimmermann telegram had been stolen by American spies in Mexico, and so they blamed that failure on Mexican security. They still did not realize that the telegram had in fact been intercepted and deciphered by the British, and that the Zimmermann .. | Simon Singh | ||
| de4b80d | Because a quantum computer deals with 1's and 0's that are in a quantum superposition, they are called quantum bits, or qubits (pronounced "cubits"). The advantage of qubits becomes even clearer when we consider more particles." | Simon Singh | ||
| 06d7998 | diagonally polarized photons are in a quantum quandary when confronted by a vertical Polaroid filter. | Simon Singh | ||
| c0903d2 | half of them at random will be blocked, and half will pass through, and those that do pass through will be reoriented with a vertical polarization. | Simon Singh | ||
| 159507c | significance of the key, as opposed to the algorithm, is an enduring principle of cryptography. It was definitively stated in 1883 by the Dutch linguist Auguste Kerckhoffs von Nieuwenhof in his book La Cryptographie militaire: "Kerckhoffs' Principle: The security of a cryptosystem must not depend on keeping secret the crypto-algorithm. The security depends only on keeping secret the key." | Simon Singh | ||
| 2c990f8 | 250 qubits, it is possible to represent roughly 1075 combinations, which is greater than the number of atoms in the universe. If it were possible to achieve the appropriate superposition with 250 particles, then a quantum computer could perform 1075 simultaneous computations, | Simon Singh | ||
| 0e82f83 | The letters a and l are the most common in Arabic, partly because of the definite article al-, whereas the letter j appears only a tenth as frequently. | Simon Singh | ||
| efa15ae | the Arab scholars were also capable of destroying ciphers. They in fact invented cryptanalysis, the science of unscrambling a message without knowledge of the key. | Simon Singh |