Nonpadded

Nonpadded is an adjective used to describe data, values, or inputs that have not been padded with extra bytes or bits to reach a required length, block size, or alignment. Padding is a deliberate addition used in various computing contexts to simplify processing or to obscure the true length of content. Nonpadded data, by contrast, contains only the original content without additional padding.

In cryptography and data transmission, many algorithms operate on fixed-size blocks. When data is nonpadded, its length must be a multiple of the block size, or an alternative method must be used. Some APIs expose a NoPadding option, meaning no padding is applied (for example, certain configurations of AES in block modes). If data does not meet the block-size requirement, an error occurs. Using no padding can improve efficiency but may require manual handling of message boundaries and can reveal information about the original length, which padding schemes are often designed to conceal.

Nonpadded form can also refer to representations without leading zeros or to framing in protocols where message length is determined without padding. In practice, nonpadded data must be interpreted within the context of the surrounding protocol or system; compatibility and security considerations are important, particularly regarding length leakage and alignment. Related concepts include padding, padding schemes, and padding oracle attacks.