Cryptography
https://www.linuxjournal.com/
enQuantum Cryptography
https://www.linuxjournal.com/content/quantum-cryptography
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<div class="field field--name-node-author field--type-ds field--label-hidden field--item">by <a title="View user profile." href="https://www.linuxjournal.com/users/subhendu-bera" lang="" about="https://www.linuxjournal.com/users/subhendu-bera" typeof="schema:Person" property="schema:name" datatype="" xml:lang="">Subhendu Bera</a></div>
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Classical cryptography provides security based on unproven
mathematical assumptions and depends on the technology available to
an eavesdropper. But, these things might not be enough in the near future to
guarantee
cyber security. We need something that
provides unconditional security. We need quantum cryptography.
</p>
<p>
Imagine you want to send a message to your friend, and you don't
want others to be able to read the message. You lock your message in a box
using a key and send the box to your friend. Your friend also has
a key to unlock that box, so he easily can open the box and read the
message. In general, this is the technique used by cryptographic
algorithms. Locking the message in the box is like encryption, and
unlocking the box is like decryption. Before sending the message to the
receiver,
the data is encrypted using an encryption algorithm and a secret key. On
the receiver side, the encrypted data is decrypted using the reverse
encryption algorithm.
</p>
<p>
Classical cryptographic algorithms mostly rely on
mathematical approaches to secure key transmission. The security they
offer is based on unproven assumptions and depends on the technology
available to an eavesdropper. But, rapidly growing parallel
and quantum technologies may be a threat to these classical cryptography
techniques in the near future. One of the solutions to these threats is quantum
cryptography.
</p>
<p>
What is quantum cryptography? Quantum cryptography is
a complex topic, because it brings into play something most people find
hard to understand—quantum mechanics. So first, let's focus on some basic
quantum physics that you'll need to know to understand this article.
</p>
<span class="h3-replacement">
Simple Quantum Physics</span>
<p>
Quantum, in physics, is a discrete natural unit, or packet of energy,
charge, angular momentum or other physical property. Light, for example,
appears in some respects as a continuous electromagnetic wave, but on
the submicroscopic level, it is emitted and absorbed in discrete amounts or
quanta. These particle-like packets (quanta) of light are called photons,
a term also applicable to quanta of other forms of electromagnetic energy,
such as X rays and gamma rays.
</p>
<p>
One unique thing about quanta is that they
can exist in all of their possible states at once. This also applies
to photons. This means that in whatever direction a photon can
spin—say,
diagonally, vertically and horizontally—it does so all at once. Quantum
of light in this state is called unpolarized photons. This is like
someone moving north, south, east, west, up and down all at the same
time. This property is called superposition. One thing you should
keep in mind is that measuring something that is in its superposition
causes it to collapse into a definite state (one of all the possible
states). Figure 1 should help describe superposition.
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Tue, 22 Apr 2014 17:32:48 +0000Subhendu Bera1335673 at https://www.linuxjournal.comElliptic Curve Cryptography
https://www.linuxjournal.com/content/elliptic-curve-cryptography
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<div class="field field--name-node-author field--type-ds field--label-hidden field--item">by <a title="View user profile." href="https://www.linuxjournal.com/users/joe-hendrix" lang="" about="https://www.linuxjournal.com/users/joe-hendrix" typeof="schema:Person" property="schema:name" datatype="" xml:lang="">Joe Hendrix</a></div>
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When it comes to public key cryptography, most systems today are still stuck in
the 1970s. On December 14, 1977, two events occurred that would change the
world: Paramount Pictures released <em>Saturday Night
Fever</em>, and MIT filed the
patent for RSA. Just as <em>Saturday Night Fever</em> helped popularize disco through its
choreography and soundtrack, RSA helped popularize cryptography by allowing two
parties to communicate securely without a shared secret.
</p>
<p>
Public key techniques, such as RSA, have revolutionized cryptography and form the
basis for Web site encryption via SSL/TLS, server administration via SSH, secure
e-mail and IP encryption (IPsec). They do this by splitting the shared secret
key used in traditional cryptography into two parts: a public key for
identifying
oneself and a secret key for proving an identity electronically. Although the
popularity of disco has waned, most Web sites today that use encryption still
are using RSA.
</p>
<p>
Since the 1970s, newer techniques have been developed that offer better security
with smaller key sizes than RSA. One major breakthrough is the development of
cryptography based on the mathematical theory of elliptic curves, called ECC
(Elliptic Curve Cryptography). Although ECC has a reputation for being quite
complex, it has been integrated into popular open-source cryptographic software
including OpenSSH and OpenSSL, and it's not inherently any more difficult to use than
RSA. In this article, I describe ECC and show how it can be used with recent
versions of OpenSSH and OpenSSL.
</p>
<p>
Not all cryptographic algorithms are equal. For a fixed key or output length,
one algorithm may provide much more security than another. This is particularly
true when comparing different types of algorithms, such as comparing public and
symmetric key algorithms. To help make sense of this, the National Institute of
Standards and Technology (NIST) reviews the academic literature on attacking
cryptographic algorithms and makes recommendations on the actual security provided
by different algorithms (see Table 1 from 2011).
</p></div>
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Mon, 08 Apr 2013 15:10:49 +0000Joe Hendrix1084447 at https://www.linuxjournal.com