The term 'de-perimeterised' was coined in a 2001 Royal Mail paper about ink-stained cash, seeding the Jericho Forum and eventually Zero Trust

The information-security term "de-perimeterised" — the rejection of the network "castle-and-moat" model, where everything inside a firewall is trusted by default — did not originate in networking. Per Spencer & Pizio (2024), it was coined in a 2001 paper, "Value-less security," by Jon Measham of the Royal Mail Research Group Security Team, built on the image of banknotes stained worthless by an anti-theft ink canister. The paper "greatly influenced the founders of the Jericho Forum," the industry group (2003–2013) that campaigned against the perimeter model and popularized "de-perimeterisation" as its rallying term. Forrester analyst John Kindervag drew on Jericho Forum thinking to coin "Zero Trust" in 2010, the label that displaced "de-perimeterisation" in industry usage while carrying its logic forward.

The lineage is: postal-security metaphor (2001) → Jericho Forum coinage → Zero Trust rebrand (2010). The mechanism underneath — devalue what an attacker would gain rather than only guard the boundary around it — is developed further in claim-axytrans-eradicate-temptation-devalued-cash-in-transit-loot, which traces the ink-staining technique itself to a cash-transport company. The manufactured-history angle of the same rebrand is treated separately in claim-cheswick-1990-chewy-centre-criticism-recast-as-zero-trust-naive-past.