In this paper, an improved version of RC4 based hash function is proposed and we call it RC4-BHF. RC4-BHF is much efficient than well-known hash functions (e.g., MD4, MD5 and SHA-1) and it is designed for radio-frequency identification (RFID) devices, which other hash functions do not apply. The structure of RC4-BHF is absolutely different from the broken hash function classes (e.g., MD family, SHA family) so that people cannot use the existing attack strategies to break it. RC4-BHF is very simple and efficient, and confirmed that it is collision resistant, preimage resistant, and second preimage resistant, and it rules out many popular attacks of hash function.