Computer-implemented method and system of tamper-evident recording of a plurality of service data items

A system of tamper-evident recording of service data, comprising at least a processing device, the processing device comprising:

• a network interface, configured to connect to a communication network for sending and receiving data;
• a service module, connected with the network interface and configured to receive a plurality of service data items and for each service data item, to compute an associated data item verification fingerprint using a fingerprint function;
• a compression module, configured to compute an aggregated verification fingerprint from at least a plurality of data item verification fingerprints using at least one one-way compression function, so that the aggregated verification fingerprint has a bit length, which is less than a bit length of a concatenation of the data item verification fingerprints;
• and
• a blockchain connector module, connected with the compression module and the network interface and configured to connect with a plurality of blockchains and to transmit the aggregated verification fingerprint to the plurality of blockchains to allow storing the aggregated verification fingerprint in the plurality of blockchains decoupled from the service data items;
• wherein the compression module is further configured to compute the aggregated verification fingerprint through computation of a hash tree from the plurality of data item verification fingerprints;
• wherein for at least a first data item verification fingerprint of the plurality of data item verification fingerprints, a first authentication path comprising one or more hashes and a second authentication path comprising one or more hashes are determined in the hash tree, which first authentication path is associated with a branch path from the first data item verification fingerprint to the root hash in a first blockchain in which the aggregated verification fingerprint is stored, and which second authentication path is associated with a branch path from the first data item verification fingerprint in a second blockchain in which the aggregated verification fingerprint is stored;
• wherein the blockchain connector module is further configured to:
• store the one or more hashes of said first authentication path in a verification database;
• store the aggregated verification fingerprint in at least a first block of the plurality of blockchains, wherein an identifier of the first block is stored in the verification database;
• and
• store the first data item verification fingerprint in the verification database with the one or more hashes of said first authentication path and correlated the first data item verification fingerprint with the one or more hashes of said first authentication path.