To my knowledge, the first reference to the idea and principles of signatures for detecting network attacks dates back to 1987. This was a scientific paper by Dorothy E. Denning from Stanford Research Institute (SRI) (Here’s the link to the paper). According to the publication’s records, it was sent to the editors in 1985, but was published almost two years later(Manuscript was received December 20, 1985; revised August 1, 1986). This work was supported by…