The present invention is a computer-implemented key exchange system and methods for improving the usability of encryption technologies such as Public Key Infrastructure (PKI). One aspect of the present invention includes registering users, verifying user identity, and classifying users such that the users may send a communications such that communication recipients can verify the user identity and classification of the communication sender. Another aspect of the present invention includes users initiating relationships with other users, approving the establishment of relationships, and exchanging encryption keys between users after the establishment of a relationship.