Privacy-preserving publish-subscribe protocol in a cloud-assisted broadcast model

A non-transitory computer readable storage medium including instructions that, when executed by a client, causes the client to:

• receive, by the client from a third party, an interest-based key associated with a tree structure having a pseudonym of an interest as a root and the client as a leaf;
• receive, by the client from the server, an encrypted item encrypted with a key associated with a conditional oblivious transfer protocol;
• receive, by the client from the server, an encrypted key for decrypting the encrypted item, wherein the encrypted key is encrypted using a topic-based key associated with a tree structure having a pseudonym of a topic as a root and the client as a leaf;
• and
• attempt, by the client, to decrypt the encrypted key to obtain the interest-based key and attempt to decrypt the encrypted item with the obtained interest-based key,
• wherein the encrypted item is decryptable by the client with the key associated with the conditional oblivious transfer protocol when the key associated with the conditional oblivious transfer protocol is decryptable with the obtained interest-based key.

A computer system, comprising:

• a memory;
• a processing device, coupled to the memory, the processing device to:
• receive from a third party a topic-based key associated with a tree structure having a pseudonym of a topic as a root and at least one client as a leaf;
• encrypt a key associated with a conditional oblivious transfer protocol using the topic-based key;
• encrypt an item with the key associated with the conditional oblivious transfer protocol;
• and
• transmit the encrypted key and the encrypted item to a plurality of clients.