Well, you mentioned integer factorization, that immediately leads me to RSA, which then leads me to PKI, and then leads me to cryptosystem. Combining it with th

Well, you mentioned integer factorization, that immediately leads me to RSA, which then leads me to PKI, and then leads me to cryptosystem. Combining it with the Knapsack problem, I was ultimately there for MH knapsack cryptosystem, which is unfortunately cracked [1]. [1]: https://en.wikipedia.org/wiki/Merkle%E2%80%93Hellman_knapsack_cryptosystem https://en.wikipedia.org/wiki/Merkle%E2%80%93Hellman_knapsac...