User controlled sharing of personal and contact information using a blockchain

A method for propagating updates to user profile information, comprising:

• adding, to a blockchain, a first block that includes:
• a first transaction ID, and
• a first version of user profile information encrypted using a first encryption key;
• communicating, to a plurality of entity computing devices that are to use the user profile information, the first transaction ID and a first decryption key that is able to decrypt information encrypted with the first encryption key;
• and
• updating the user profile information by adding, to the blockchain, a second block that refers to the first transaction ID and includes a second version of the profile information encrypted using the first encryption key.

One or more non-transitory computer-readable media storing instructions which, when executed by one or more processors, cause:

• adding, to a first block of a blockchain, a first transaction entry that includes:
• a first transaction ID of the first transaction entry, and
• user profile information;
• communicating, to a plurality of entity computing devices that are to use the user profile information, the first transaction ID;
• receiving a request to read data from the blockchain, the request including the first transaction ID of the first transaction entry and an entity account ID associated with a particular entity computing device of the plurality of entity computing devices;
• in response to the request to read data from the blockchain, reading the first transaction entry from the first block;
• in response to reading the first transaction entry from the first block, communicating, to the particular entity computing device that is to use the user profile information, the first transaction entry;
• and
• adding, to a second block of the blockchain, a second transaction entry that includes a reference to the first transaction ID and data indicating an acknowledgment that the entity account ID has read the first transaction entry.

One or more non-transitory computer-readable media storing instructions which, when executed by one or more processors, cause:

• adding, to a blockchain, a first block that includes:
• a first transaction ID, and
• a first version of user profile information encrypted using a first encryption key;
• communicating, to a plurality of entity computing devices that are to use the user profile information, the first transaction ID and a first decryption key that is able to decrypt information encrypted with the first encryption key;
• and
• updating the user profile information by adding, to the blockchain, a second block that refers to the first transaction ID and includes a second version of the profile information encrypted using the first encryption key.