Collating anonymized data

Apparatus for providing anonymized data, comprising a first server comprising a first processor connected to a first data source, and a first network interface, wherein said first processor is configured to:

• generate a first shared encryption key;
• receive, from a networked location, a first message comprising a first encrypted identifier that said first server is unable to decrypt;
• generate, from said first data source, a first dataset that may comprise data corresponding to said first encrypted identifier;
• and
• return said first dataset to said networked location;
• wherein said step of generating said first dataset comprises steps of:
• obtaining, from said first data source, a set of at least one local unencrypted identifier;
• and
• for each local unencrypted identifier in said set:
• verifying said first encrypted identifier against said local unencrypted identifier to obtain either a successful or failed verification by calculating a first value using said first shared encryption key, said first encrypted identifier and said local unencrypted identifier, and verifying said first encrypted identifier against said first value, and
• when said verification is successful, obtaining, from said first data source, first corresponding data that is associated with said local unencrypted identifier, wherein said first dataset comprises said first corresponding data.