An arrangement of goods, comprising: a plurality of units of an article, the units equipped with respective contactlessly readable tags; each of said tags comprising a respective memory configured to store a respective signature; the signatures stored in the memories of said tags appearing scrambled relative to one another when read by a reader. Also, a method, comprising: contactlessly reading a first signature from a first tag affixed to a first unit of an article; contactlessly reading a second signature from a second tag affixed to a second unit of the same article, the second signature appearing scrambled relative to the first signature; decrypting the first signature with a key to reveal (I) an identifier associated with the article and (II) a first scrambling code; and decrypting the second signature with the same key to reveal the same identifier and a second scrambling code different from the first scrambling code.