Techniques for enhancing the security of a communication device when conducting a transaction using the communication device may include receiving a cryptogram generation key replenishment request that includes transaction log information derived from transaction data stored in a transaction log on a communication device, verifying that the transaction log information in the replenishment request is consistent with the previously received transaction information, and providing a new cryptogram generation key to the communication device in response to verifying the transaction log information in the replenishment request.