Gartner Research

Cryptography

Published: 14 September 2011

ID: G00214493

Analyst(s): Ramon Krikken

Summary

This Decision Point covers the choices to be made once an organization has determined to use cryptography for encryption or authentication. Situations examined include how much information should be encrypted under a single key; how often to change keys and how long to trust keys; how to select key lengths, hash sizes, and cryptographic algorithms and protocols; whether to use hardware or software; requirements for cryptographic validations; and whether to run the system in a validated cryptographic configuration mode.

Table Of Contents

Decision Point

Decision Context

  • Related Decisions

Evaluation Criteria

  • Requirements and Constraints
    • Time Frames and Surety Levels
    • Speed vs. Security vs. Modularity and Compatibility (in Both Key Length and Algorithm Choice)
    • Strength of the Environment
  • Principles

Alternatives

  • Vetted vs. Unvetted Algorithms and Protocols
  • FIPS Validation
  • FIPS-Compliant Configuration
  • Algorithm and Protocol Choice
  • Key Length and Hash Size
  • Key Granularity
  • Key Rotation
  • Protection of Keys
  • Hardware vs. Software

Future Developments

Decision Tool

  • Vetted vs. Unvetted Solutions Position
    • Consider vetted and unvetted algorithms, protocols, and implementations based on analysis of risks, costs, and benefits.
    • Always use vetted algorithms, protocols, and implementations.
  • FIPS Validation Position
    • Choose FIPS 140-2-validated systems or modules over noncertified ones.
    • Consider systems or modules validated at FIPS 140-2 level 3.
    • Consider systems or modules validated at FIPS 140-2 level 4.
  • FIPS-Compliant Configuration Position
    • Make a risk-based decision to keep or change the system and re-evaluate.
    • Run the system in an appropriately secure configuration.
    • Run the system in FIPS mode.
  • Algorithm and Protocol Choice Position
    • Use an appropriate implementation of the specified algorithm or protocol.
    • Make a risk-based decision to keep the system and implement compensating controls, or to not use the system.
    • Choose an appropriate implementation of a current algorithm or protocol that meets system requirements.
  • Key Length and Hash Size Position
    • Focus on resistance against password brute force attacks before deciding on key length and hash size.
    • Choose the largest possible key length or hash size for the algorithm.
    • Choose a key length or hash size with an expected strength equal to or greater than the confidentiality and/or authenticity requirements of the information.
    • Choose a key length with an expected strength equal to or greater than the validity or rotation period of the authentication key.
  • Key Granularity Position
    • Select a key granularity based on risk, performance, and manageability considerations.
  • Key Rotation Position
    • Key rotation is based on risk and manageability requirements.
  • Protection of Keys Position
    • Protect keys at least to the level of the information.
  • Hardware vs. Software Position
    • Use hardware.
    • Use software.

Revision History

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