Volume hologram

One of the most common types of hologram (together with surface relief holograms), these are mass-produced through optical copying of a master hologram, so they retain more of the optical properties of that master than the mechanical process of surface relief...

Void label

Tamper-evident labels that, when removal is attempted, reveal a covert ‘VOID’ message. Also refers to anti-copy labels that, upon scanning, reveal the word ‘VOID’ in the copy.

Visible digital seal (VDS)

A cryptographically signed data structure containing document features, encoded as a 2D barcode and printed on a document. The use of a VDS is recommended by ISO 22381:2018 as a trusted entry point to allow all stakeholders to authenticate a unique identifier without...


The reformation of cellulose to give a textile fibre that may carry security features and be embedded into security paper.