(finance) A line representing the relationship between expected return and systematic risk, thus a graphical representation of the CAPM. It is valid both for portfolios and individual assets.

(US) A nine-digit number issued to citizens, permanent residents, and temporary (working) residents under section 205(c)(2) of the Social Security Act, codified as 42 U.S.C. § 405(c)(2). The number is issued to an individual by the Social Security Administration. Its primary purpose is to track individuals for taxation purposes. Abbreviated as SSN. In recent years the SSN has become a de facto national identification number.

(finance) an asset-backed security whose cash flows are backed by the principal and interest payments of a set of mortgage loans.

plural of social security number

(Canada) The Canadian foreign signals intelligence and cryptography agency.

(computer security) Relying on a potential attacker's lack of knowledge will maintain security.

plural of security market line

Alternative form of security through obscurity

(cryptography) Not decodable with all available computer power.

Of a device: such that, if it fails, it does so in a way that will cause little or no harm to other devices and personnel.