Which of the following describes the technique of showing only the last four digits of a social security number?

The technique of showing only the last four digits of a social security number is best described as masking. Masking involves obscuring specific data within a dataset to protect sensitive information while still allowing for some level of visibility. By displaying only the last four digits, the full social security number remains hidden, thus maintaining privacy and reducing the risk of unauthorized access to sensitive personal information. This method is commonly used in various applications where full data exposure is unnecessary for the intended use, striking a balance between usability and security.

Other concepts such as hiding would imply complete removal of the information, making it invisible, while partial display may suggest a less systematic approach of showing parts of data without proper context. Data truncation generally refers to cutting off a portion of the data entirely and is used more in contexts where the data itself is shortened or eliminated rather than selectively obscured for privacy. Thus, masking is the most precise term for this act of displaying only a segment of sensitive information.