A property is a measurable or definable characteristic of something. In materials science, that can mean hardness, strength, or conductivity; in cyber security, it can also mean a system’s confidentiality, integrity, availability, or a protocol’s cryptographic behavior. Properties are useful because they turn a vague claim into something that can be tested, compared, and verified.
In practice, security teams rely on properties to judge whether a control works as intended. For example, encryption should preserve confidentiality, an access-control rule should preserve authorization boundaries, and a hash function should preserve integrity by making changes detectable. Attackers often succeed by breaking an assumed property, such as trust, isolation, or randomness. Careful measurement and verification matter because a defense is only as strong as the property it actually delivers, not the one it is assumed to have.