padder

A padder is a term used in various industries to describe a device, mechanism, or piece of software that adds padding to data or material to meet a size, alignment, or processing requirement. The concept is common in manufacturing, data security, and digital communications, where padding helps ensure consistent processing, protection, or efficiency.

In textile processing, a padder is a machine used to apply padding liquor or finishing solutions to fabrics. The fabric is immersed in a bath, passed through rollers (padder rollers) to squeeze out excess liquid, and then dried or cured. Padders enable controlled impregnation, elasticity, and color fastness and are used in dyeing, finishing, and coating lines. The padder can be part of a continuous or batch operation and may be integrated with washing and drying sections.

In cryptography and computer data handling, a padder is a component or routine that appends padding bytes to a message to bring its length to a required multiple, typically a block size. This is essential for block cipher modes like ECB or CBC, which operate on fixed-size blocks. Common schemes include PKCS#7 and zero padding. After decryption, corresponding unpadding removes the added bytes. Padding also appears in network and storage contexts to align data to fixed boundaries or to satisfy protocol framing.

In summary, padder denotes both machinery in textiles and software mechanisms to introduce padding, reflecting the general need to reach uniform lengths and reliable processing across domains.