This paper outlines the development of a new QNX utility designed to generate /etc/shadow files for QNX systems, generating both standard QNX shadow entries with the currently implemented PBKDF2 key derivation function, and a proposed new key derivation function, Argon2. The goal of introducing a new key derivation function is to increase the resistance to brute-force password guessing attacks. The tool, mkshadow, was built as a Linux utility supporting the generation of both types of shadow entries, specified via a configuration file. Testing was performed against both cryptographic strategies using the password cracking tools, Hashcat and John the Ripper. Results show that the use of Argon2 in the place of PBKDF2 can drastically increase a systems resistance, especially when a large number of passwords are being cracked in parallel. Optimal configurations for a good balance of high security and usability are discussed in the Discussion and Conclusion sections of this paper.