The book "Trust, Privacy and Security in Digital Business" documents the refereed contributions of the 12th International Conference on Trust, Privacy and Security in Digital Business, which took place in 2015 in Valencia, Spain. It includes 17 revised full texts selected from 45 submitted papers. The topics of the contributions are diverse and cover important aspects relevant to the digital business world. The subjects addressed range from access control to trust and reputation in pervasive environments, as well as security and privacy issues in mobile and cloud environments. The careful selection and review of the papers ensure that readers gain valuable insights into current challenges and solutions in the field of digital security and privacy.