magnet

A piece of material that attracts some metals by magnetism.

An alluring or attractive person or thing.

He always had a girl on his arm – he's a bit of a babe magnet.

Iron and coal were the magnets that drew railways to this land of lovely valleys and silent mountains—for such it was a century-and-a-half ago, before man blackened the valleys with the smoke of his forges, scarred the green hills with his shafts and waste-heaps, and drove the salmon from the quiet Rhondda and the murmuring Taff.

Ellipsis of magnet link.

Magnets are thus used to create a package of cryptologic information and bundling^([sic]) it together.