<p><em>Taken from Wikipedia, the free encyclopedia:</em></p>

<p>Cryptography is the field concerned with linguistic and
mathematical techniques for securing information, particularly
in communications. Historically, cryptography was concerned
solely with encryption; that is, means of converting information
from its normal, comprehensible form into an incomprehensible
format, rendering it unreadable without secret knowledge.
Encryption was used primarily to ensure secrecy in important
communications, such as those of spies, military leaders,
and diplomats.</p>

<p>In recent decades, however, the field of cryptography has
expanded its remit: modern cryptography provides mechanisms for
more than just keeping secrets and has a variety of applications
including, for example, authentication, digital signatures,
electronic voting and digital cash. Moreover, people without
extraordinary needs for secrecy use cryptographic technology,
which is often built transparently into much of computing and
telecommunications infrastructure.</p>
