Patent attributes
Multiple, separately administrated computer systems storing slices of the cipher text of a Personally Identifiable Information (PII) data item that is represented by a token. The token is used as a substitute of the data item. The data item is encrypted using a public key. To recover the data item, a complete set of the slices is retrieved from the separate computer systems and decrypted using the private key corresponding to the public key. Instances and circumstances of the usages of the data item can be recorded under the token in a blockchain ledger in connection with the retrieval and/or decryption of the cipher text. A data item owner may use the data item and the public key to recreate the cipher text, retrieve the token stored with the cipher text in the separate computer systems, and then query the ledger for a usage history of the data item.
