padfinding

Padfinding is a term used in several technical fields to describe locating or recovering a 'pad'—a designated element used for transferring, aligning, or encrypting information. Because the word pad has different meanings in different contexts, padfinding is not a single discipline but a cross-domain concept.

In electronics manufacturing, pad finding refers to locating component pads on a printed circuit board (PCB) and alignment marks to enable automated assembly and inspection. Modern systems use machine vision and feature matching to identify pad geometry, spacing, and fiducials, providing the coordinates needed for pick-and-place robots, soldering, and quality control. Robust pad finding improves yield and reduces misplacement.

In pad printing, pad finding describes the calibration of the silicone transfer pad with respect to the engraving plate and the substrate. It involves determining the pad position, orientation, and actuation timing to ensure consistent ink transfer and repeatable print quality. Operators use test patterns and alignment procedures to tune pad travel, pressure, and dwell time.

In cryptography, pad finding denotes recovering the pad, or keystream, used in a XOR-based scheme or stream cipher. Under known-plaintext or chosen-plaintext conditions, the pad can be reconstructed by XORing ciphertext with the corresponding plaintext, removing secrecy assumptions. Pad finding highlights the vulnerability of systems that reuse pads or rely on weak randomness.

Because padfinding has different meanings in different domains, the term is most informative when the context specifies whether it refers to hardware fabrication, manufacturing processes, or cryptographic security.