None

  This term is used to indicate an important recommendation. Ignoring the recommendation could result in undesirable results. Note that should may be coupled with not to become should not.
Source(s):
NIST SP 800-108
NIST SP 800-135 Rev. 1
NIST SP 800-56A Rev. 2 [Superseded]
NIST SP 800-56B Rev. 2
NIST SP 800-56B Rev. 1 [Superseded]

  Is recommended to.
Source(s):
NIST SP 800-38F under should

  An important recommendation. Ignoring the recommendation could result in undesirable results. Note that should may be coupled with not to become should not.
Source(s):
NIST SP 800-56C [Superseded]

  This term is used to indicate a very important recommendation. Ignoring the recommendation could result in undesirable results. Note that should may be coupled with not to become should not.
Source(s):
NIST SP 800-57 Part 1 Rev. 4 [Superseded]
NIST SP 800-57 Part 1 Rev. 5
NIST SP 800-57 Part 1 Rev. 3 [Superseded]

  Used to indicate a strong recommendation, but not a requirement of this Recommendation.
Source(s):
NIST SP 800-89

  Used to indicate a highly desirable feature for a DRBG mechanism that is not necessarily required by this Recommendation. "Should" may be coupled with "not" to become "should not."
Source(s):
NIST SP 800-90A Rev. 1

  The term used to indicate an important recommendation. Ignoring the recommendation could result in undesirable results. Note that should may be coupled with not to become should not.
Source(s):
NIST SP 800-90B

  When shown in a bold font, this term is used to indicate an important recommendation. Ignoring the recommendation could result in undesirable results. Note that should may be coupled with not to become should not.
Source(s):
NIST SP 800-175B Rev. 1

  An objective that can be met.  It is used when a specific requirement is not feasible in some situations or with common current technology.  Non- conformance to such requirements requires less justification and should be more readily approved.
Source(s):
NISTIR 5153