Padding

Padding is the addition of extra space or data that is added to a structure, message, or item to meet a requirement or improve handling. In computing, padding is used to align data in memory, ensuring that values start at addresses compatible with the processor. Compilers may insert padding between fields of a data structure to satisfy alignment rules, increasing memory usage but improving access speed. Padding bytes may also be appended to a message or file to reach a required length, or to obscure the true length. Common padding schemes in cryptography include PKCS#7 and ANSI X.923; padding is added before encryption, and must be removed after decryption. Incorrect padding handling can lead to security vulnerabilities.

In web and application design, CSS padding creates space inside an element between its content and its border; it is distinct from margin, which separates the element from others.

In textiles and manufacturing, padding refers to soft filler material placed in cushions, clothing, or upholstery to provide shape and insulation.

In typography and layout, padding may describe the interior space around content within a container, affecting readability and composition.