Which technique describes a legal values constraint?

Which technique describes a legal values constraint?

• A. Birthdate after 1/1/1900
• B. Encrypting data at rest
• C. Storing passwords in plain text
• D. Allowing nulls in SSN

Answer: (A)

A legal values constraint restricts the data to values that are permitted by policy or business rules. Requiring a birthdate to be after a specific date, such as January 1, 1900, constrains the field to a plausible and authorized range. This ensures the value entered is meaningful and compliant with domain rules, making it a classic example of enforcing legal values. Encrypting data at rest is about protecting data confidentiality, not restricting the values that can be stored. Storing passwords in plain text goes against security best practices, not about value constraints. Allowing nulls in an SSN concerns whether the field can be empty, rather than validating that a value falls within an acceptable range.

A legal values constraint restricts the data to values that are permitted by policy or business rules. Requiring a birthdate to be after a specific date, such as January 1, 1900, constrains the field to a plausible and authorized range. This ensures the value entered is meaningful and compliant with domain rules, making it a classic example of enforcing legal values.

Encrypting data at rest is about protecting data confidentiality, not restricting the values that can be stored. Storing passwords in plain text goes against security best practices, not about value constraints. Allowing nulls in an SSN concerns whether the field can be empty, rather than validating that a value falls within an acceptable range.