Contact discovery service with privacy aspect

A non-transitory computer readable storage medium configured to store instructions that, in response to being executed by at least one processor included in a client device, cause the client device to implement a discovery protocol that includes privacy aspects by carrying out steps that include:

• generating an identifier and a first hash value for an item of personal information data
• (PID) related to a contact stored in an address book of the client device;
• transmitting a request to a service that includes the identifier and a key comprising N most significant bits of the first hash value;
• receiving a response to the request, the response including the identifier and a payload that has been encrypted with a second hash value associated with a potential contact that is registered with the service;
• and
• in response to determining that the identifier generated by the client device matches the identifier included in the response:
• attempting to decrypt the payload with the first hash value to access information related to the potential contact included in the payload, wherein:
• when the payload can be decrypted, then the contact matches the potential contact and a decrypted version of the payload includes information associated with a user account for the potential contact in a recognized format, or
• when the payload cannot be decrypted, then the contact does not match the potential contact and the response is discarded.

A client device that implements a discovery protocol with privacy aspects, the client device comprising:

• at least one hardware processor;
• and
• a non-transitory computer-readable storage medium storing instructions that, when executed by the at least one hardware processor, cause the client device to:
• generate a universally unique identifier (UUID);
• generate a first hash value derived from an item of information associated with a contact stored in an address book of the client device;
• transmit a request to a contact discovery service that includes the UUID and at least a portion of the first hash value;
• receive a response to the request, the response including the UUID and an encrypted payload that has been encrypted utilizing a second hash value for a corresponding item of information related to a potential contact as an encryption key;
• and
• in response to determining that the UUID generated by the client device matches the UUID included in the response:
• determine whether the encrypted payload can be decrypted utilizing a decryption key derived from the item of information associated with the contact stored in the address book of the client device;
• and
• when the encrypted payload can be decrypted, then the contact matches the potential contact and a decrypted version of the encrypted payload includes information related to a user account of the potential contact registered with the contact discovery service, or
• when the encrypted payload cannot be decrypted, then the contact does not match the potential contact and the response is discarded.