Cryptography Reference
In-Depth Information
custodians taking part in the key ceremony, but not necessarily simultaneously
(for example, it may be required that the key custodians never meet).
Throughout the key ceremony, the witnesses record the events and any
deviations from the defined procedure are noted. At the end, an official record
is presented to the key manager.
Validation
. If necessary, following the completion of the key ceremony, the official
record can be scrutinised to validate that the correct procedure was followed
(perhaps as part of an audit).
This proposed key ceremony is meant only as an illustration, and precise details
of key ceremonies will depend on local requirements. The point, however,
is to demonstrate the importance of key management policies, practices and
procedures. Regardless of the underlying cryptographic technology and hardware,
the security of the key ceremony itself is down to an orchestrated sequence of
actions by human beings, which can only be controlled by procedures of this type.
In this chapter we have discussed key management, the aspect of cryptography that
is of greatest relevance to users of cryptography, since it is the part most likely to
require decision making and process design in individual application environments.
We have observed that key management is always necessary, but never easy. In
particular, we have:
• Stressed the importance of keeping in mind the entire cryptographic key
lifecycle, from key generation through to key destruction.
• Examined the various phases of the cryptographic key lifecycle in detail.
• Noted that key management must ultimately be governed by policies, practices
and procedures.
This chapter dealt with management of keys that need to be kept secret. In the next
chapter we examine further issues that arise when managing key pairs for use in
public-key cryptography.
Despite the importance of key management, it is often a topic that is overlooked
in introductions to cryptography and there are few dedicated and comprehensive
overviews of the topic. Probably the best overall treatment is NIST's recom-
mendations for key management, published as NIST 800-57 [139]. The first
part of this special publication provides a thorough grounding in key manage-
ment and the second part includes advice on key management governance.
NIST 800-130 [142] deals with the design of key management systems. The
first part of ISO/IEC 11770 [4] presents a general overview and basic model for
