The use of weak passwords is a significant vulnerability in computer information system security, and this issue is also present in the digital applications of grain storage information systems. Simple hashing algorithms have obvious limitations when dealing with weak passwords. Based on the actual application of grain storage software systems, this paper proposed a method to enhance weak password protection by using a hashing algorithm as the foundation, combined with the introduction of salt values and high-order reflections for strengthening, along with multiple rehashing operations. Validation and analysis showed that this method increased the hashing strength of weak passwords, and effectively prevented dictionary attacks or rainbow table attacks, which could achieve the effective protection for the transmission and storage of weak passwords. Additionally, it had low complexity, and was easy to implement. It also had an average computational latency of approximately 2.5 ms, which was imperceptible to users. This method is suitable for the construction and management of digital grain storage information systems, providing robust security protection.