In a world where people must subject themselves to high scrutiny in every process they initiate, and in a world where the digital environment grows incessantly, we anticipate more online services asking for personal attributes and their need to trust in such attributes. For tackling such need, we describe a proposal for a secure, decentralized and shared repository of certified personal attributes. Individuals benefit because they have full control over the disclosure of their set of certified attributes (e.g. to assert their identities to service providers). The certifying entities benefit from a blockchain-based, resilient and decentralized infrastructure, avoiding the higher costs of an always-on, centralized infrastructure, while retaining the power to issue and revoke certified attributes. Finally service providers benefit from the correctness and freshness of the certified attributes that individuals disclosed to them.