Authentication of data in the field of works of art, financial transactions, medical records using blockchain technology; Computer network design and computer software design for the subject matter, field or industry; Computer programming consultancy; Computer software consulting; Computer software development; Computer systems analysis; Design and development of on-line computer software systems; Design for others in the field of computer networks, software, and engineering for the subject matter, field or industry; Design, development, and implementation of software for authenticating digital signatures; Services for maintenance of computer software; Technical support services, namely, troubleshooting of computer software problems