R. PoovendranBaras, John S.Recent literature presents several rooted tree based member deletion/revocation schemes trying to simultaneously minimize the key storage whileproviding efficient member deletion/revocation. Many of these approaches have different solutions and provide different values for the number of keys to be stored and distributed. <p>In this paper, we show that these problems can be systematically studied using basic concepts from information theory. In particular, we show that the entropy of member revocation event plays a major role in defining the key allocation requirements. We then relate the entropy of member revocation event to bounds on the key length. <p>We also show that the optimal Huffman coding strategy used in leads to security weaknesses. A method for generating key management schemes to withstand varying degrees of member collusion is also presented.<p><i>ATIRP 4th Annual Conference</i>en-UScodingsecure multicastkey managementkey lengthGlobal Communication SystemsTechnical Report