Methods, systems, and apparatus, including computer programs encoded on computer storage media, for
processing encrypted and hashed versions of
raw data. One of the methods includes receiving, by a
system, a message that comprises an encrypted version of
raw data and a hash of the
raw data; determining, using the hash of the raw data, a first location in a hash map; inserting the encrypted version of the raw data to the first location in the hash map; determining to transmit, to another
system, data for a second location in the hash map; selecting, using the second location, at least a subset of the data for the second location in the hash map; and transmitting, to the other
system, the subset of the data for the second location in the hash map.