In 1974, Ralph Merkle, a grad student at UC Berkley, submitted a project proposal for the CS224 course. It was the first 'paper' on public key cryptography.
No, I am not joking.
His professor asked him to pursue another project, because this project's descripotion was "muddled terribly". Merkle then re-wrote. Eventually, he dropped the course because the professor showed only little interest.
Merkle then sent the paper to ACM only to receive the following response after a review by an "experienced cryptography expert":
"I am sorry to have to inform you that the paper is not in the main stream of present cryptography thinking and I would not recommend that it be published in the Communications of the ACM." "Experience shows that it is extremely dangerous to transmit key information in the clear."
The editor at the Communications of the ACM, also said:
.. particularly bothered by the fact that there are no references to the literature.
The paper was finally published by CACM 3 years after the first submission. Two years later, in 1976, Whitfield Diffie and Martin Hellman published similar work. A 1977 U.S. Patent 4,200,770 credits Hellman, Diffie, and Merkle as inventors