System and method to improve user authentication for enhanced security of cryptographically protected communication sessions

A system comprising:

• computer-readable memory storing a private key assigned to a sender;
• and
• one or more processors in communication with the computer-readable memory and programmed by executable instructions to at least:
• generate first encrypted data using first data and a public key assigned to an intended recipient;
• send, to a computing device, a first transmission comprising the first encrypted data;
• receive, from the computing device, a second transmission comprising (1) a first digital signature signed by a private key assigned to the intended recipient and (2) second encrypted data encrypted using a public key assigned to the sender, wherein the second encrypted data comprises an encrypted version of the first data and second data, and wherein the first digital signature comprises a representation of the first data and the second data;
• recover the first data and the second data from the second transmission using the private key assigned to the sender;
• verify that the second transmission originated from the intended recipient based at least partly on the first digital signature;
• generate third encrypted data using at least a portion of the second data and the public key assigned to the intended recipient;
• generate a second digital signature singed by the private key assigned to the sender, wherein the second digital signature comprises a representation of at least the portion of the second data;
• and
• send, to the computing device, a third transmission comprising the second digital signature and the third encrypted data, wherein the second digital signature is provided to verify non-tampering of the second data during transit from the computing device.