Re-keying algorithms for symmetric cryptosystems

In symmetric cryptosystems, each key has its lifetime. Thus, re-keying algorithms are commonly employed. In this paper, we propose a re-keying algorithm, which ensures the secrecy of other session keys even if the session key of some period is compromised. This re-keying algorithm requires a block cipher and two one-way hash functions. We provide the security analysis and also discuss an implementation option.