The invention of the Diffie-Hellman key exchange, the first public asymmetric-key cryptosystem, transformed information security in 1976, allowing ciphered communications without a secure initial key exchange and becoming the basic building block that enabled ecommerce on the Internet.  In this video, Whitfield Diffie talks about his protocol and all the surrounding events the lead to the paper New Directions in Cryptography, conjointly written with Martin Hellman.

Unfortunately, there has never been another breakthrough like that one, even though the field of cryptography research has grown by multiple orders of magnitude since them. It seems that imaginative ways to restrict access to information that enable latent markets in information are very hard to come by. Even so, my bets are on the almost current practical schemes to perform Secure Multi-Party Computation, Zero-Knowledge Proofs, Fully Homomorphic Cryptography and Private Information Retrieval, with direct applications to finance.