Protection of Intellectual Proprietary Rights is currently one of the most important barriers to electronic commerce of digital contents over networks. Authors and content providers understand the immense advantages of the digital world but show some reserve. However, technologies and techniques to protect IPR in digital content exist, their deployment in a coherent way is still in an early stage. In this paper, we describe the approach followed by the OCTALIS Project towards and effective electronic commerce of digital images. After describing briefly enabling technologies, the emphasis is on contract negotiation over Internet through a secure dialog between the Service Provider and the User
