Auditable distribution of a data file

A server connectable to a plurality of clients, comprising:

• a processor;
• and,
• a computer-readable data storage medium to store a data file having a plurality of chunks and to store a computer program executable by the processor,
• wherein the computer program comprises:
• a first computer program part to deliver the chunks of the data file and identifiers of the chunks to the clients;
• a second computer program part to receive a digest for each chunk received by each client, the chunk generated by the client that received the chunk using at least a part of the chunk and further data of the client, the further data known to the server;
• a third computer program part to determine for each chunk an identity of the client that received the chunk by comparing each digest received to the chunks of the data file and to the further data of each client;
• and,
• a fourth computer program part to store the identity of the client that possesses each chunk,
• wherein receiving the digest for each chunk, determining the identity of the client that received the chunk, and storing the identity of the client that received the chunk provide for auditable data distribution of the data file among the clients from the server.

A client connectable to a server and to an additional client, comprising:

• a processor;
• and,
• a computer-readable data storage medium to store at least a computer program executable by the processor,
• wherein the computer program comprises:
• a first computer program part to receive a chunk of a data file from the server;
• a second computer program part to generate a digest using at least a part of the chunk and further data of the client, the further data known to the server;
• and,
• a third computer program part to send the digest to the server,
• wherein generating the digest by the client, and sending the digest from the client to the server provide for auditable data distribution of the data file.

A computer-readable data storage medium storing a computer program executable by a processor of a server, such that execution of the computer program by the processor causes a method to be performed, the method comprising:

• delivering a plurality of chunks of a data file and identifiers of the chunks to a plurality of clients;
• for each chunk of the data file,
• receiving, from the client that received the chunk of the data file, a digest generated by the client that received the chunk of the data file using at least a part of the chunk and further data of the client that received the chunk, the further data known to the server;
• determining an identity of the client that received the chunk, by comparing the digest to the chunks that the server has sent and to the further data known to the server;
• and,
• storing the identity of the client that received the chunk,
• wherein receiving the digest for each chunk, determining the identity of the client that received the chunk, and storing the identity of the client that received the chunk provide for auditable data distribution of the data file among the clients from the server.