An online identity can be verified based on data from multiple identity sources stored in a blockchain. For example, a request for a token is received from an entity for authenticating an online identity of the entity to an online service. The request can be stored in a blockchain that represents the online identity of the entity by adding a new block to the blockchain. The new block can include data indicating the request for the token. The token can be generated based on the one or more ordered blocks in the blockchain. The token can be transmitted to the entity. The token can be received from the online service. Confirmation of the online identity of the entity can be transmitted to the online service based on receiving the token from the online service.