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You will note that civilization survived. Many of us regard that period as a golden age in American political culture.
It is poor policy to clamp down indiscriminately on a technology just because some criminals might be able to use it to their advantage.
A business must be able to guarantee the privacy and security of financial transactions, and the only way to do this is to employ strong encryption.
All of this is done automatically by Alice’s Web browser (e.g., Netscape or Explorer) in conjunction with the company’s computer.
In America there are no restrictions on key size, but U.S. software companies are still not allowed to export Web products that offer strong encryption.
In short, if Internet commerce is to thrive, consumers around the world must have proper security, and businesses will not tolerate crippled encryption.
Naturally, corporations want to protect this information from hackers who might infiltrate the computer and steal the information.
In early 1998, Mercury Rising told the story of a new, supposedly unbreakable NSA cipher which is inadvertently deciphered by a nine-year-old autistic savant.
Also in 1998, Hollywood released Enemy of the State, which dealt with an NSA plot to murder a politician who supports a bill in favor of strong encryption.
The most famous trial of cryptographic key escrow was the American Escrowed Encryption Standard, adopted in 1994.
At the very moment she bought the clipper phone, a copy of the private key in the chip would be split into two halves, and each half would be sent to two separate Federal authorities for storage.
The U.S. Government employed clipper and capstone for its own communications, and made it obligatory for companies involved in government business to adopt the American Escrowed Encryption Standard. Other businesses and individuals were free to use other forms of encryption, but the government hoped that clipper and capstone would gradually become the nation’s favorite form of encryption.
Cryptographic experts pointed out that just one crooked employee could undermine the whole system by selling escrowed keys to the highest bidder.
For example, a European business in America might fear that its messages were being intercepted by American trade officials in an attempt to obtain secrets that might give American rivals a competitive edge.
“The people involved in the crypto debate are all intelligent, honorable and proescrow, but they never possess more than two of these qualities at once.”
In January 1999, France repealed its anticryptography laws, which had previously been the most restrictive in Western Europe, probably as a result of pressure from the business community.
In other words, one of the problems with public key cryptography is being sure that you have the genuine public key of the person with whom you wish to communicate. Certification authorities are organizations that will verify that a public key does indeed correspond to a particular person.
Some argue that TTPs are effectively a reincarnation of key escrow, and that law enforcers would be tempted to bully TTPs into giving up a client’s keys during a police investigation.
However, I suspect that in the near future the proencryption lobby will initially win the argument, mainly because no country will want to have encryption laws that prohibit e-commerce.
At the same time, the kudos of being the subject of an FBI inquiry boosted the reputation of PGP, and Zimmermann’s creation spread via the Internet even more quickly—after all, this was the encryption software that was so secure that it frightened the Feds.
In general, European attitudes toward encryption were, and still are, more liberal, and there would be no restrictions on exporting a European version of PGP around the world. Furthermore, the RSA patent wrangle was not an issue in Europe, because RSA patents did not apply outside America.
There was the additional problem that Zimmermann was being supported by major institutions, such as the Massachusetts Institute of Technology Press, which had published PGP in a 600-page book. The book was being distributed around the world, so prosecuting Zimmermann would have meant prosecuting the MIT Press.
An FBI trial might achieve nothing more than an embarrassing constitutional debate about the right to privacy, thereby stirring up yet more public sympathy in favor of widespread encryption.
The invention of public key cryptography and the political debate that surrounds the use of strong cryptography bring us up to the present day, and it is clear that the cryptographers are winning the information war.
Previous experience, however, tells us that every so-called unbreakable cipher has, sooner or later, succumbed to cryptanalysis.
The tale of James Ellis and GCHQ warns us that there may already be remarkable breakthroughs hidden behind the veil of government secrecy.
Their success is demonstrated by the fact that cryptanalysts are in greater demand than ever before-the NSA is still the world’s largest employer of mathematicians.
Codebreakers continue to use old-fashioned techniques like traffic analysis; if codebreakers cannot fathom the contents of a message, at least they might be able to find out who is sending it, and to whom it is being sent, which in itself can be telling. A more recent development is the so-called tempest attack, which aims to detect the electromagnetic signals emitted by the electronics in a computer’s display unit.
In America, it is necessary to obtain a government license before buying such shielding material, which suggests that organizations such as the FBI regularly rely on tempest surveillance.
A variation on the Trojan horse is a brand-new piece of encryption software that seems secure, but which actually contains a backdoor, something that allows its designers to decrypt everybody’s messages.
Although traffic analysis, tempest attacks, viruses and Trojan horses are all useful techniques for gathering information, cryptanalysts realize that their real goal is to find a way of cracking the RSA cipher, the cornerstone of modern encryption.
Before going any further, please heed a warning originally given by Niels Bohr, one of the fathers of quantum mechanics: “Anyone who can contemplate quantum mechanics without getting dizzy hasn’t understood it.”
The ducks had provided Young with a deeper insight into the true nature of light, and he eventually published “The Undulatory Theory of Light,” an all-time classic among physics papers.
We do not need to discuss this duality any further, except to say that modern physics thinks of a beam of light as consisting of countless individual particles, known as photons, which exhibit wave-like properties.
There is no way to explain the phenomenon in terms of the classical laws of physics, by which we mean the traditional laws that were developed to explain how everyday objects behave.
Each possibility is called a state, and because the photon fulfills both possibilities it is said to be in a superposition of states.
In comparison, the old-fashioned classical view is that the photon must have passed through one of the two slits, and we simply do not know which one—this seems much more sensible than the quantum view, but unfortunately it cannot explain the observed result.
Superposition occurs only when we lose sight of an object, and it is a way of describing an object during a period of ambiguity.
The act of looking at the cat forces it to be in one particular state, and at that very moment the superposition disappears.
The many-worlds interpretation claims that upon leaving the filament the photon has two choices-either it passes through the left slit or the right slit—at which point the universe divides into two universes, and in one universe the photon goes through the left slit, and in the other universe the photon goes through the right slit. These two universes somehow interfere with each other, which accounts for the striped pattern. Followers of the many-worlds interpretation believe that whenever an object has the potential to enter one of several possible states, the universe splits into many
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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.
One of the pioneers of quantum computing is David Deutsch, a British physicist who began working on the concept in 1984, when he attended a conference on the theory of computation.
The tacit assumption was that all computers essentially operated according to the laws of classical physics, but Deutsch was convinced that computers ought to obey the laws of quantum physics instead, because quantum laws are more fundamental.
In other words, an ordinary computer can address only one question at a time, and if there are several questions it has to address them sequentially. However, with a quantum computer, the two questions could be combined as a superposition of two states and inputted simultaneously-the machine itself would then enter a superposition of two states, one for each question. Or, according to the many-worlds interpretation, the machine would enter two different universes, and answer each version of the question in a different universe. Regardless of the interpretation, the quantum computer can address
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Hence, when a particle is not being observed it can enter a superposition of states, which means that it is spinning in both directions at the same time, and so is representing both 0 and 1 at the same time. Alternatively, we can think of the particle entering two different universes: in one universe it spins eastward and represents 1, while in the other it spins westward and represents 0.
However, if the particle is spinning westward and put in a box out of our view, and we fire a weak pulse of energy at it, then we have no idea whether its spin has been changed.
The operator inputs the seven particles, while they are still in a superposition of states, into the quantum computer, which then performs its calculations as if it were testing all 128 numbers simultaneously.
Some physicists view the quantum computer as a single entity that performs the same calculation simultaneously on 128 numbers. Others view it as 128 entities, each in a separate universe, each performing just one calculation.
When traditional computers operate on 1’s and 0’s, the 1’s and 0’s are called bits, which is short for binary digits. 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”).
In short, the counterfeiter cannot measure the polarizations in a genuine bill because he does not know which type of photon is in each light trap, and cannot therefore know how to orient the Polaroid filter in order to measure it correctly. On the other hand, the bank is able to check the polarizations in a genuine bill, because it originally chose the polarizations, and so knows how to orient the Polaroid filter for each one.
