Integrity of transactional memory of card computing devices in case of card tear events

A card computing device, comprising:

• a processor;
• a first memory;
• a second memory;
• and
• a third memory comprising instructions that, when executed by the processor, cause the processor to:
• copy transaction rollback data to a buffer in the first memory, the transaction rollback data comprising data used to restore a heap in the second memory to a first state prior to initiating a transaction on the card computing device;
• calculate a checksum for the transaction rollback data;
• storing the calculated checksum and a checksum pointer in the first memory, wherein the checksum pointer refers to a last valid location in a transactional memory region of the second memory for which the checksum is calculated, as the transaction rollback data is written to the first memory;
• write, to the transactional memory region, the transaction rollback data from the buffer and the checksum and the checksum pointer from the first memory;
• perform at least part of the transaction by writing new transaction data to the heap, wherein the transaction rollback data is useable to restore the heap to the first state if the transaction was not completed, upon reconnection of the card computing device after determining that a card tear event has occurred, wherein the card tear event comprises a disconnection of the card computing device from a card computing device reader.

A non-transitory computer readable medium comprising instructions that, when executed by a processor, perform a method comprising:

• copying transaction rollback data to a buffer in a first memory, the transaction rollback data comprising data used to restore a heap in a second memory of a card computing device to a first state prior to initiating a transaction on the card computing device;
• calculating a checksum for the transaction rollback data;
• storing the calculated checksum and a checksum pointer in the first memory, wherein the checksum pointer refers to a last valid location in a transactional memory region of the second memory for which the checksum is calculated, as the transaction rollback data is written to the first memory;
• writing, to the transactional memory region, the transaction rollback data from the buffer and the checksum and the checksum pointer from the first memory;
• and
• performing at least part of the transaction by writing new transaction data to the heap, wherein the transaction rollback data is useable to restore the heap to the first state if the transaction was not completed, upon reconnection of the card computing device after determining that a card tear event has occurred, wherein the card tear event comprises a disconnection of the card computing device from a card computing device reader.