Abstract: One example embodiment of the present invention is a method for conducting an imperative removal of at least one data record among peers to support ability to forget in blockchain. Each peer participating to a blockchain system has its own copy of a blockchain in a blockchain system. The method includes depositing the at least one data record to its designated data storage system by at least one peer; storing a cryptographic hashing pointer as a data item in a first block of its own copy of the blockchain by each peer; storing a deletion item in a second block of its own copy of the blockchain by each peer; and deleting the data record from the designated data storage system by each peer when the deletion item for the data record is found on the blockchain.

Abstract: One example embodiment is a method of proving the immutability of digital records in a first entity. The method includes storing the digital records in a sequence of blocks by the first entity; regularly sending the hash value of the blocks by the first entity to the external party; computing a re-computed hash value of a specific block from the digital records stored at the first entity by a second entity; obtaining a retrieved hash value of the specific block from the external party by mapping a key index by the second entity; and proving that the digital records have not been changed up to the specific block if the re-computed hash value is the same as the retrieved hash value by the second entity.

Abstract: One example embodiment is a method of proving the immutability of digital records in a first entity. The method includes storing the digital records in a sequence of blocks by the first entity; regularly sending the hash value of the blocks by the first entity to the external party; computing a re-computed hash value of a specific block from the digital records stored at the first entity by a second entity; obtaining a retrieved hash value of the specific block from the external party by mapping a key index by the second entity; and proving that the digital records have not been changed up to the specific block if the re-computed hash value is the same as the retrieved hash value by the second entity.

Abstract: One example embodiment of the present invention is a method for conducting an imperative removal of at least one data record among peers to support ability to forget in blockchain. Each peer participating to a blockchain system has its own copy of a blockchain in a blockchain system. The method includes depositing the at least one data record to its designated data storage system by at least one peer; storing a cryptographic hashing pointer as a data item in a first block of its own copy of the blockchain by each peer; storing a deletion item in a second block of its own copy of the blockchain by each peer; and deleting the data record from the designated data storage system by each peer when the deletion item for the data record is found on the blockchain.