Simon Singh

The Code Book: The Secret History of Codes and Code-breaking

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Valentyna Brusenkohas quoted4 years ago
Just as Whit Diffie predicted in the early 1970s, we are now entering the Information Age, a post-industrial era in which information is the most valuable commodity.
Valentyna Brusenkohas quoted4 years ago
The uncertainty principle is another weird consequence of quantum theory.
Wiesner’s quantum mo
Valentyna Brusenkohas quoted4 years ago
It is this ability to block certain photons that explains how Polaroid sunglasses work. In fact, you can demonstrate the effect of Polaroid filters by experimenting with a pair of Polaroid sunglasses. First remove one lens, and close that eye so that you are looking with just the other eye through the remaining lens. Not surprisingly, the world looks quite dark because the lens blocks many of the photons that would otherwise have reached your eye. At this point, all the photons reaching your eye have the same polarisation. Next, hold the other lens in front of the lens you are looking through, and rotate it slowly. At one point in the rotation, the loose lens will have no effect on the amount of light reaching your eye because its orientation is the same as the fixed lens – all the photons that get through the loose lens also pass through the fixed lens. If you now rotate the loose lens through 90°, it will turn completely black. In this configuration, the polarisation of the loose lens is perpendicular to the polarisation of the fixed lens, so that any photons that get through the loose lens are blocked by the fixed lens. If you now rotate the loose lens by 45°, then you reach an intermediate stage in which the lenses are partially misaligned, and half of the photons that pass through the loose lens manage to get through the fixed lens.
Valentyna Brusenkohas quoted4 years ago
The angle of vibration is known as the polarisation of the photon, and a light bulb generates photons of all polarisations,
Valentyna Brusenkohas quoted4 years ago
The angle of vibration is known as the polarisation of the photon,
Valentyna Brusenkohas quoted4 years ago
The angle of vibration is known as the polarisation of the photon, and a light bulb generates photons of all polarisations, which means that some photons will vibrate up and down, some from side to side, and others at all angles in between.
Valentyna Brusenkohas quoted4 years ago
Wiesner was proposing the bizarre concept of quantum money, which had the great advantage of being impossible to counterfeit.
Valentyna Brusenkohas quoted4 years ago
Whether we adopt superposition or the many-worlds interpretation, quantum theory is a perplexing philosophy. Nevertheless, it has shown itself to be the most successful and practical scientific theory ever conceived. Besides its unique capacity to explain the result of Young’s experiment, quantum theory successfully explains many other phenomena. Only quantum theory allows physicists to calculate the consequences of nuclear reactions in power stations; only quantum theory can explain the wonders of DNA; only quantum theory explains how the sun shines; only quantum theory can be used to design the laser that reads the CDs in your stereo. Thus, like it or not, we live in a quantum world.
Valentyna Brusenkohas quoted4 years ago
Anyone who can contemplate quantum mechanics without getting dizzy hasn’t understood it.’ In other words, prepare to meet some rather bizarre ideas.
Valentyna Brusenkohas quoted4 years ago
tempest attack, which aims to detect the electromagnetic signals emitted by the electronics in a computer’s display unit. If Eve parks a van outside Alice’s house, she can use sensitive tempest equipment to identify each individual keystroke that Alice makes on her computer. This would allow Eve to intercept the message as it is typed into the computer, before it is encrypted
Valentyna Brusenkohas quoted4 years ago
Kenneth Neil Cukier, a technology journalist, has written that: ‘The people involved in the crypto debate are all intelligent, honorable and pro-escrow, but they never possess more than two of these qualities at once.’
Valentyna Brusenkohas quoted4 years ago
To summarise the situation, it is clear that the debate is between two camps: civil libertarians and businesses are in favour of strong encryption, while law enforcers are in favour of severe restrictions. In general, popular opinion appears to be swinging behind the pro-encryption alliance, who have been helped by a sympathetic media and a couple of Hollywood films.
Valentyna Brusenkohas quoted4 years ago
is poor policy to clamp down indiscriminately on a technology just because some criminals might be able to use it to their advantage. For example, any U.S. citizen can freely buy a pair of gloves, even though a burglar might use them to ransack a house without leaving fingerprints. Cryptography is a data-protection technology, just as gloves are a hand-protection technology. Cryptography protects data from hackers, corporate spies, and con artists, whereas gloves protect hands from cuts, scrapes, heat, cold, and infection. The former can frustrate FBI wire-tapping, and the latter can thwart FBI fingerprint analysis. Cryptography and gloves are both dirt-cheap and widely available. In fact, you can download good cryptographic software from the Internet for less than the price of a good pair of gloves.
Valentyna Brusenkohas quoted4 years ago
Not surprisingly, among the advocates of cryptographic freedom are some of the inventors of public-key cryptography. Whitfield Diffie states that individuals have enjoyed complete privacy for most of history:
In the 1790s, when the Bill of Rights was ratified, any two people could have a private conversation – with a certainty no one in the world enjoys today – by walking a few meters down the road and looking to see no one was hiding in the bushes. There were no recording devices, parabolic microphones, or laser interferometers bouncing off their eyeglasses. You will note that civilization survived. Many of us regard that period as a golden age in American political culture.
Valentyna Brusenkohas quoted4 years ago
Law enforcers fear that the Internet coupled with cryptography will help criminals to communicate and coordinate their efforts, and they are particularly concerned about the so-called Four Horsemen of the Infocalypse – drug dealers, organised crime, terrorists and paedophiles – the groups who will benefit most from encryption.
Valentyna Brusenkohas quoted4 years ago
Because the U.S. Government included encryption software within its definition of munitions, along with missiles, mortars and machine guns, PGP could not be exported without a licence from the State Department. In other words, Zimmermann was accused of being an arms dealer because he had exported PGP via the Internet.
Valentyna Brusenkohas quoted4 years ago
This is analogous to driftnet fishing – making a quantitative and qualitative Orwellian difference to the health of democracy.
Valentyna Brusenkohas quoted4 years ago
However, for over two thousand years mathematicians have tried and failed to find a shortcut, and at the moment factoring remains an enormously time-consuming calculation. Most mathematicians believe that factoring is an inherently difficult task, and that there is some mathematical law that forbids any shortcut.
Valentyna Brusenkohas quoted4 years ago
The system, dubbed RSA (Rivest, Shamir, Adleman) as opposed to ARS, went on to become the most influential cipher in modern cryptography.
Valentyna Brusenkohas quoted4 years ago
history of science, and it forced the cryptographic establishment to rewrite the rules of encryption. Diffie, Hellman and Merkle publicly demonstrated their discovery at the National Computer Conference in June 1976, and astonished the audience of cryptoexperts. The following year they filed for a patent. Henceforth, Alice and Bob no longer had to meet in order to exchange a key. Instead, Alice could just call Bob on the phone, exchange a couple of numbers with him, mutually establish a secret key and then proceed to encrypt.
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