Karger and Schell in 1974 conceptualised the idea of trap doors built into compilers in their Multics Security Review.
Although Ken Thompson is responsible for popularising the idea through his Turing award speech in 1984.
Edit: Ken Thompson mentions the paper in the acknowledgements of his Turing award speech.
"""
Acknowledgment. I first read of the possibility of such
a Trojan horse in an Air Force critique [4] of the security of an early implementation of Multics. I cannot find
a more specific reference to this document. I would
appreciate it if anyone who can supply this reference
would let me know.
"""
[1] https://www.oreilly.com/library/view/aws-cookbook/9781492092...
[2] https://docs.aws.amazon.com/IAM/latest/UserGuide/access-anal...