Part 1: General - Computer Security Resource Center - National ...

March, 2007
making such decisions. Systems should offer algorithm suite options that provide for
future growth.
3. System design: The new system should be designed to meet the minimum
performance and security requirements. This is often a difficult task, since
performance and security goals may conflict. All aspects of security (e.g., physical
security, computer security, operational security, and personnel security) are
involved. If a current system is to be modified to incorporate the new algorithms, the
consequences need to be analyzed. For example, the existing system may require
significant modifications to accommodate the footprints (e.g., key sizes, block sizes,
etc.) of the new algorithms. In addition, the security measures (other than the
cryptographic algorithms) retained from the current system should be reviewed to
assure that they will continue to be effective in the new system.
4. Pre-implementation evaluation: Strong cryptography may be poorly implemented.
Therefore no change over to new cryptographic techniques should be made without
an evaluation as to how effective and secure they are in the system.
5. Testing: Any complex system should be tested before it is employed.
6. Training: If the new system requires that new or different tasks (e.g., key
management procedures) be performed, then the individuals who will perform those
tasks should be properly trained. Features that are thought to be improvements may
be viewed as annoyances by an untrained user.
7. System implementation and transition: Care should be taken to implement the
system as close as possible to the design. Exceptions should be noted.
8. Transition: A transition plan should be developed and followed so that the change
over from the old to the new system runs as smoothly as possible.
9. Post-implementation evaluation: The system should be evaluated to verify that the
system as implemented meets the minimum security requirement.
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