Password-based authentication has been widely deployed in practice due to its simplicity and efficiency. Storing pass-words and deriving cryptographic keys from passwords in a secure manner are crucial for many security systems and services. However, choices of well-studied password hash-ing algorithms are extremely limited, as their security re-quirements and design principles are different from common cryptographic algorithms. In this paper, we propose two simple and practical password hashing algorithms, Pleco and Plectron. They are built upon well-understood cryp-tographic algorithms, and combine advantages of symmetric and asymmetric primitives. By employing the Rabin cryp-tosystem, we prove that the one-wayness of Pleco is at least as strong as the hard problem of integer factorization. In addition, both password hashing algorithms are designed to be sequential memory-hard, in order to thwart large-scale password cracking by parallel hardware, such as GPUs, FP-GAs, and ASICs. Moreover, total computation and memory consumptions of Pleco and Plectron are tunable through their cost parameters
