The encryption scheme based on Forward Key Rotation is such a scheme that only the authorized person is allowed access to the designated files and the previous versions. In this study, we present a Forward Key Rotation storage scheme based on discrete logarithm and prove its security under random oracle model. Moreover, we propose another improved Forward Key storage scheme from pairing on elliptic curves. Compared to the scheme presented by Kallahalla et al. our scheme uses relatively short keys to provide equivalent security. In addition, the re-generated keys can be verified to ensure that the keys are valid in the improved scheme.