Blockchain technologies are being touted as a way to protect individual privacy. Blockchain app developers and theorists, often out of a genuine desire to protect people and their privacy, have devoted considerable efforts to devising ways that the blockchain can be used to verify aspects of a static digital identity. However, these notions of a static, single, and accurate digital identity ignore the reality of how people's identities work, and especially the plural, time-varying, and fictionalizing elements of personal identity. This chapter charts out ways that people’s multiple identities may be affected and undermined by the development of public and unmodifiable ledgers of transactions and contractual undertakings. Following on from this discussion, the chapter applies a clearer model of identity to the blockchain use-cases of marriage, money laundering, and criminal justice records, and draws conclusions for regulators, blockchain applications developers, and the general public.