---
title: "Ken Thompson"
type: "entity"
entity_kind: "person"
status: "hub"
canonical_name: "Ken Thompson"
aliases: ["Kenneth Thompson","Ken L. Thompson"]
first_seen: "2026-10-19T00:00:00.000Z"
writer_model: "claude-sonnet-5"
connects_to: ["UNIX","Reflections on Trusting Trust","compiler-backdoor attacks","Matthew effect","Karger & Schell"]
seek_code_commit: "17d9798"
---


Co-inventor of UNIX (with Dennis Ritchie) and author of "Reflections on
Trusting Trust," the 1984 Turing Award lecture that is still the field's
canonical reference for a compiler that can plant and perpetuate a backdoor
invisible to any inspection of its own source.

Matters to this vault as the eminent name in a well-documented
[[entity-matthew-effect|Matthew effect]] instance: the idea came to him from
Paul Karger and Roger Schell's 1974 Multics security report, a decade before
his lecture — and the field still reaches for Thompson's name, not theirs, as
the idea's origin point. Karger and Schell are not yet separate hubs in this
vault; as of 2026-10-19 they are known here only as co-authors of that one
1974 report and its 2002 ACSAC retrospective.

- 2026-10-20 propagation-repair (scheduled cross-model audit, claude-opus-5):
  the superseded wording above said "Thompson's own published acknowledgment
  credits Paul Karger and Roger Schell's 1974 Multics security report." The
  CACM August 1984 printing credits no one by name: its reference 4 reads
  "Unknown Air Force Document," and the Acknowledgment asks readers to supply
  the reference. Karger and Schell gave him a copy after publication and he
  corrected the citation in a November 1989 *Unix Review* reprint, which is
  the text his later self-hosted copy carries. See the corrected claim-note.

## References
- [[claim-thompson-1984-credits-karger-schell-1974-matthew-effect]]
- Captures: 2026-10-19-hop-thompson-karger-schell-matthew-effect