The characteristics of the wireless network determine the requirement of lightweight cryptography. Towards the huge cost of an existing algorithm such as MD5, this paper proposes a message digest scheme based on the RC4 algorithm which broadens the application area of the RC4 and decreases the requirement of resource or cost. To test the randomicity of the algorithm＇s di- gest, fifteen kinds of randomicity test to NIST randomicity test standard had been done, and the comparative analysis which compares the digest＇s randomicity of the algorithm with MD5 had been performed as well. The performance of the algorithm had been analyzed in aspects of mono-directivity, randomicity, practicality and complexness. Statistic tests and analysis results illustrated that our scheme was of low cost of computing, good statistic performance, high running speed and lightweight.
