MILAN, Oct 15 (Reuters) - Italian fashion group OTB has joined a consortium formed by luxury goods heavyweights LVMH (LVMH.PA), Prada(1913.HK) and Richemont-owned Cartier that uses blockchain technology to trace the origin of high-end products to fight counterfeiting. The platform, dubbed Aura, will allow consumers to follow a product life cycle by accessing a sort of digital database storing information in a way that it cannot be changed, tampered with or hacked. The initiative, launched in April and a rare case of collaboration between rival brands, is aimed at improving transparency about where and how luxury goods are made, and also provide owners with certificates of authenticity. OTB - which stands for Only The Brave - owns brands including Diesel, Maison Margiela, Marni and Viktor&Rolf and acquired Jil Sander in March.