Cryptography Reference
In-Depth Information
We have now completed our introduction to everyday cryptography. We
have seen that cryptography is essentially a toolkit of mathematical
techniques for implementing the core security services that are required to protect
information. We have learnt many important lessons about cryptography along
the way. In particular:
Cryptography is much more than encryption
. The term 'cryptography' derives
from the Greek for 'hidden writing', which inappropriately implies that
cryptography is primarily about providing confidentiality. Although con-
fidentiality is important, the cryptographic toolkit consists of far more
than just tools for encryption. Cryptographic primitives can be employed
to provide a host of different security services. As well as confidentiality
mechanisms, we have studied mechanisms for providing data integrity,
data origin authentication, entity authentication and non-repudiation. While
cryptographers have designed many even more specialised tools, the majority
of applications of cryptography can be built from the mechanisms that we
discussed in this topic.
Cryptography is an everyday technology
. Cryptography has become a technol-
ogy that most of us use almost every day of our lives. We have examined several
of these applications in this topic. However, the majority of users do not realise
that they are using cryptography on a daily basis. Cryptography may literally
mean 'hidden writing', but it is really the
use
of cryptography that is hidden in
most applications. In many cases we have no alternative to cryptography for
providing most of these security services, so it is reasonable to expect that this
everyday use of cryptography will continue for the foreseeable future.
Cryptography is a process
. Cryptography does nothing on its own. While it
is a crucial underlying component of any information security architecture,
cryptography is nothing more than that. Achieving the security services that
cryptographic mechanisms are designed to provide requires cryptography to
be treated as a process. The correct cryptographic mechanisms need to be
selected, combined and used in an appropriate manner. Cryptography needs to
be carefully incorporated into other technologies. Cryptographic keys undergo
a complete lifecycle, which must be overseen by sound key management. If any
