In this paper, we discuss security properties for synchronous stream ciphers. Let the key size and claimed security level be k. Following an initial proposal by Hawkes and Rose , we argue that a synchronous stream cipher should encrypt at most 2^(k/2) plaintext blocks before changing the key. We claim further that a synchronous stream cipher should ideally provide for IV sizes of both k/2 and k, with the second size being mandatory. In this context, recent results by Hong and Sarkar  are also briefl y discussed.
|Publication status||Published - 2005|