Abstract: An encryption key management method includes: receiving a data registration request from a supplier terminal, determining a data identifier associated with the content data, encrypting a master key with a public key of the supplier terminal, and providing the supplier terminal with the master key encrypted with the public key of the supplier terminal, the data identifier, and a key update count value; receiving a subscription application related to the data identifier from a first subscriber terminal, encrypting the master key with a public key of the first subscriber terminal, and providing the first subscriber terminal with the master key encrypted with the public key of the first subscriber terminal and the key update count value; receiving encrypted content data encrypted with the symmetric key and a hash for the content data from the supplier terminal; and transmitting the encrypted content data and the hash to the first subscriber terminal.

Abstract: A Merkle tree-based data management method may comprise: aligning data into two-dimensional square matrix; calculating a hash value of each node of the two-dimensional square matrix; calculating hash values of each row of the two-dimensional square matrix; generating an additional column with nodes having the hash values of each row; calculating hash values of each column of the two-dimensional square matrix; generating an additional row with nodes having hash values of each column; and calculating a Merkle root by concatenating the hash values of the additional column and the hash values of the additional row.