A method of exchanging sensitive information among a plurality of entity systems comprising: applying a hash function to portions of sensitive information of a first entity system to produce hash values; storing transaction information pertaining to transactions performed on the first entity system within a blockchain database accessible to the plurality of entity systems, wherein the transaction information includes the hash values for the portions of sensitive information, and wherein the blockchain database includes transaction information from the plurality of entity systems including hash values from others of the plurality of entity systems; comparing the hash values of the first entity system to the hash values from the others of the plurality of entity systems to determine entity systems containing information pertaining to one or more served entities common between the first entity system and the plurality of entity systems; and exchanging the sensitive information for the one or more common served entities of the first entity system with the determined entity systems containing information for the one or more common served entities, wherein the blockchain database further includes encryption parameters for encrypting data to be sent to the plurality of entity systems, and the exchanging the sensitive information comprises: encrypting the sensitive information for the common served entities utilizing the encryption parameters of each of the determined entity systems within the blockchain database, wherein the encryption parameters for a corresponding entity system are associated with a private key limiting decryption to that corresponding entity system; and transmitting the encrypted sensitive information to each of the determined entity systems for decryption via the associated private key; wherein the served entities are entities associated with served data items including sensitive information and the entity systems have access to a database management system. applying a hash function to portions of sensitive information of a first entity system to produce hash values; storing transaction information pertaining to transactions performed on the first entity system within a blockchain database accessible to the plurality of entity systems, wherein the transaction information includes the hash values for the portions of sensitive information, and wherein the blockchain database includes transaction information from the plurality of entity systems including hash values from others of the plurality of entity systems; comparing the hash values of the first entity system to the hash values from the others of the plurality of entity systems to determine entity systems containing information pertaining to one or more served entities common between the first entity system and the plurality of entity systems; and exchanging the sensitive information for the one or more common served entities of the first entity system with the determined entity systems containing information for the one or more common served entities, wherein the blockchain database further includes encryption parameters for encrypting data to be sent to the plurality of entity systems, and the exchanging the sensitive information comprises: encrypting the sensitive information for the common served entities utilizing the encryption parameters of each of the determined entity systems within the blockchain database, wherein the encryption parameters for a corresponding entity system are associated with a private key limiting decryption to that corresponding entity system; and transmitting the encrypted sensitive information to each of the determined entity systems for decryption via the associated private key; encrypting the sensitive information for the common served entities utilizing the encryption parameters of each of the determined entity systems within the blockchain database, wherein the encryption parameters for a corresponding entity system are associated with a private key limiting decryption to that corresponding entity system; and transmitting the encrypted sensitive information to each of the determined entity systems for decryption via the associated private key;