Page 109 - DCAP309_INFORMATION_SECURITY_AND_PRIVACY

Unit 8: Cryptography and Encryption

 Discuss the concept of digital signature Notes
 Understand cryptographic algorithms

Introduction

Information security is an issue that is receiving a growing attention in today’s society and one
of the main reasons for this is attributable to the Internet phenomena. During the design of
Internet, great importance was given to its functionality rather than other aspects, such as
information security, thus making it an inadequate means for certain applications. The
unpredictable success of Internet, however, has not been influenced by it’s own downfalls and it
has by now proved to be a fundamental tool that cannot be discarded in almost all sectors of
today’s economy. For this reason great effort has been invested in the improvement of the
services offered by Internet and one of these is obtained using cryptographic techniques that
render Internet not only a useful means of doing business, but at times even indispensable. In
fact, through cryptographic techniques, one can obtain: secure communication connections,
identity proof, electronic signatures (arguably safer than hand signing a check or credit card
receipt) among other benefits.

8.1 Cryptography and Encryption

Internet provides essential communication between tens of millions of people and is being
increasingly used as a tool for commerce, security becomes a tremendously important issue to
deal with.
There are many aspects to security and many applications, ranging from secure commerce and
payments to private communications and protecting passwords. One essential aspect for secure
communications is that of cryptography.

When your computer sends the information out, it scrambles it by using some key. This scrambled
information would be gibberish to anyone who didn’t have the correct key to unscramble it at
the other end.

When the information reaches its destination, it gets unscrambled by using the key. This lets the
person or website read the information correctly at the other end.
Websites that use an encrypted connection use something called SSL (Secure Sockets Layer) to
secure the information going back and forth. This is how websites like Amazon or your bank
can ensure your private information like passwords and credit card numbers are safe from
prying eyes.
Cryptography can play many different roles in user authentication. Cryptographic authentication
systems provide authentication capabilities through the use of cryptographic keys known or
possessed only by authorized entities.
Cryptography also supports authentication through its widespread use in other authentication
systems.

Example: Password systems often employ cryptography to encrypt stored password
files, card/token system often employ cryptography to protect sensitive stored information,
and hand-held password generators often employ cryptography to generate random, dynamic
passwords.

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