Cryptography Reference
In-Depth Information
Applications
We have now completed our discussion of the cryptographic toolkit and the
management of cryptographic keys. We have spent much of this discussion
highlighting issues that need to be addressed when making decisions about what
type of cryptography to implement and how to support it. It is notable that
many of these issues were dependent on the application environment. We thus
avoided making any 'decisions' about such issues during our discussion. Rather,
we focussed on presenting the pros and cons of relevant choices.
We will now examine a number of applications of cryptography. While these
may well be of independent interest, the real reason that we are studying these
applications is to indicate the types of decisions that have been taken in specific
application environments with respect to issues that we left 'open' in the previous
chapters.
While these applications are all important, and hopefully interesting, their
selection has primarily been to provide different application environments where
different decisions have been taken. We will see during this discussion that the
'right' decisions are not always taken, first time around at least. We will also see
that many decisions are taken based on tradeoffs. The chosen applications are:
Cryptography on the Internet
. SSL/TLS is one of the most ubiquitous cryp-
tographic protocols and provides an excellent example of the use of hybrid
encryption to support open application environments.
Cryptography for wireless local area networks
. The development of the
cryptography used in wireless local area network standards provides a number
of important lessons in practical cryptographic design.
Cryptography for mobile telecommunications
. GSM and UMTS provide
good examples of cryptographic design in relatively closed application
environments.
Cryptography for secure payment card transactions
. The banking industry has
been one of the longest commercial users of cryptography and a wide variety of
different techniques are used to support different types of payment transaction.
Cryptography for video broadcasting
. Pay-TVprovides a fascinating application
with relatively straightforward cryptography requiring the support of fairly
sophisticated key management.
