Data block modification

A computing device for modifying a data block of a data structure comprising a plurality of linked data blocks, wherein the data structure is stored in memory accessible to the computing device, and the computing device comprising a processor configured to:

• receive a selection of said data block comprising block data;
• create modified block data based on the block data and user input received at the computing device;
• transmit a request to a plurality of validator computing devices over a communication network, said request comprising a modification record and requesting permission to modify said data block in accordance with the modified block data, wherein said modification record comprises (i) at least one data portion identifier of said block data, each of the at least one data portion identifier associated with a respective data portion of said data block modified in creating the modified block data;
• (ii) modification information;
• (iii) a cryptographic hash of said data block when comprising the block data;
• (iv) a cryptographic hash of said data block when comprising the modified block data;
• and (v) an integrity measure;
• determine that consensus is reached by the plurality of validator computing devices that said data block can be modified in accordance with the modified block data;
• in response to said determination:
• modify said data block in accordance with the modified block data;
• and
• add a modification data block to the data structure comprising the plurality of linked data blocks, the modification data block comprising:
• the modification record and a cryptographic hash of a data block that precedes the modification data block after addition of the modification data block to the data structure.

A method of verifying a data structure comprising a plurality of linked data blocks, the method performed on a computing device, and comprising:

• for a first data block at a beginning of the data structure:
• computing a cryptographic hash of the first data block;
• determining if the cryptographic hash of the first data block matches a cryptographic hash stored in a successor data block of the first data block, and if the cryptographic hash of the first data block does not match the cryptographic hash stored in the successor data block of the first data block, storing information associated with the first data block as an entry in a list stored in memory accessible by the computing device;
• analysing each subsequent data block in the data structure after said first data block by:
• determining if said subsequent data block is a modification data block,
• wherein if said subsequent data block is not a modification data block, the method comprising:
• computing a cryptographic hash of the subsequent data block;
• determining if the cryptographic hash of the subsequent data block matches a cryptographic hash stored in a successor data block of the subsequent data block, and if the cryptographic hash of the subsequent data block does not match the cryptographic hash stored in the successor data block of the subsequent data block, storing information associated with the subsequent data block as an entry in said list;
• wherein if said subsequent data block is a modification data block, the method comprising:
• verifying an integrity measure of the modification data block;
• if said verifying the integrity measure of the modification data block is successful, determining that information in the modification data block matches information of a matching entry in said list, and in response, removing said matching entry from said list;
• in response to completion of said analysing, successfully verifying the data structure based upon detecting that said list comprises no entries.

A computing device for verifying a data structure comprising a plurality of linked data blocks, wherein the data structure is stored in memory accessible to the computing device, and the computing device comprising a processor configured to:

• for a first data block at a beginning of the data structure:
• compute a cryptographic hash of the first data block;
• determine if the cryptographic hash of the first data block matches a cryptographic hash stored in a successor data block of the first data block, and if the cryptographic hash of the first data block does not match the cryptographic hash stored in the successor data block of the first data block, storing information associated with the first data block as an entry in a list stored in memory accessible by the computing device;
• analyse each subsequent data block in the data structure after said first data block by:
• determining if said subsequent data block is a modification data block,
• wherein if said subsequent data block is not a modification data block, the processor configured to:
• compute a cryptographic hash of the subsequent data block;
• and
• determine if the cryptographic hash of the subsequent data block matches a cryptographic hash stored in a successor data block of the subsequent data block, and if the cryptographic hash of the subsequent data block does not match the cryptographic hash stored in the successor data block of the subsequent data block, storing information associated with the subsequent data block as an entry in said list;
• wherein if said subsequent data block is a modification data block, the processor is configured to:
• verify an integrity measure of the modification data block;
• if said verification of the integrity measure of the modification data block is successful, determine that information in the modification data block matches information of a matching entry in said list, and in response, remove said matching entry from said list;
• in response to completion of said analysis, successfully verify the data structure based upon detecting that said list comprises no entries.