Abstract: Methods and systems for representing a transaction using private blockchains are disclosed. In an example, a method for representing a transaction uses a private blockchain. The blockchain comprises a transaction block and a first sentinel block, the first sentinel block comprising a first previous hash field having an identical hash value as the first transaction hash field of the first transaction block, a first sentinel marker field for identifying the first sentinel block in the private blockchain, a first transaction data field containing a portion of the transactional information in the first transaction data field of the first transactional block, a first payload hash field comprising a hash value of the transaction data field of the sentinel block, and a first transactional hash field containing a first hash value of the first previous hash field and the first payload hash field; and appending the sentinel block to the transaction block.