That’s an interesting example because of how it’s a multiple discovery. You know about the secret GCHQ invention, of course, but “Merkle’s Puzzles” was invented before D-H: Merkle’s Puzzles aren’t quite like what you think of by public-key crypto (it’s proof of work, in a sense, not trapdoor function, I guess you might say), but they do give a constructive proof that it is possible to achieve the goal of bootstrapping a shared secret. It’s not great and can’t be improved, but it does it.
It’s also another example of ‘manufacturing an academic pedigree’. You’ll see a lot of people say “Merkle’s Puzzles inspired D-H”, tracing out a Whig intellectual history of citations only mildly vexed by the GCHQ multiple. But, if you ask Merkle or Diffie themselves, about how Diffie knew about Merkle’s then-unpublished work, they’ll tell you that Diffie didn’t know about the Puzzles when he invented D-H—because nobody understood or liked Merkle’s Puzzles (Diffie amusingly explains it as ‘tl;dr’). What Diffie did know was that there was a dude called Merkle somewhere who was convinced it could be done, while Diffie was certain it was impossible, and the fact that this dude disagreed with him nagged at him and kept him thinking about the problem until he solved it (making asymmetric/public-key at least a triple: GCHQ, Merkle, and D-H). Reason is adversarial.
That’s an interesting example because of how it’s a multiple discovery. You know about the secret GCHQ invention, of course, but “Merkle’s Puzzles” was invented before D-H: Merkle’s Puzzles aren’t quite like what you think of by public-key crypto (it’s proof of work, in a sense, not trapdoor function, I guess you might say), but they do give a constructive proof that it is possible to achieve the goal of bootstrapping a shared secret. It’s not great and can’t be improved, but it does it.
It’s also another example of ‘manufacturing an academic pedigree’. You’ll see a lot of people say “Merkle’s Puzzles inspired D-H”, tracing out a Whig intellectual history of citations only mildly vexed by the GCHQ multiple. But, if you ask Merkle or Diffie themselves, about how Diffie knew about Merkle’s then-unpublished work, they’ll tell you that Diffie didn’t know about the Puzzles when he invented D-H—because nobody understood or liked Merkle’s Puzzles (Diffie amusingly explains it as ‘tl;dr’). What Diffie did know was that there was a dude called Merkle somewhere who was convinced it could be done, while Diffie was certain it was impossible, and the fact that this dude disagreed with him nagged at him and kept him thinking about the problem until he solved it (making asymmetric/public-key at least a triple: GCHQ, Merkle, and D-H). Reason is adversarial.