Generating cryptographic proof of a series of transactions

A transaction processing system comprising:

• one or more transaction processors;
• and one or more computer-readable non-transitory storage media coupled to one or more of the transaction processors and comprising instructions operable when executed by one or more of the transaction processors to cause the transaction processing system to perform operations comprising:
• receiving a request from a computer system via a data communication network to verify a first transaction ledger in comparison to a second transaction ledger, the request identifying the first transaction ledger and the second transaction ledger, each of the first transaction ledger and the second transaction ledger being digitally stored in a networked online data storage device accessible to the one or more transaction processors;
• accessing the first transaction ledger and the second transaction ledger and converting the first transaction ledger and the second transaction ledger to a normalized data format;
• executing one or more cryptographic one-way hash algorithms over the first transaction ledger and the second transaction ledger to create and store in memory a first hash tree for the first transaction ledger and a second hash tree for the second transaction ledger;
• recursively traversing corresponding nodes of the first hash tree and the second hash tree until a discrepancy is found between a first verification value for a current node of the first hash tree and a second verification value for a corresponding node of the second hash tree and recursively continuing traversal until reaching corresponding leaf nodes of the first hash tree and the second hash tree;
• and
• forming and transmitting to the computer system via the data communication network, a response to the request based on a comparison of the first verification value and the second verification value, the response comprising one or more of:
• a notification of inconsistency between the first transaction ledger and the second transaction ledger;
• and a notification of records from the first transaction ledger and the second transaction ledger represented by the corresponding leaf nodes of the first hash tree and the second hash tree.