The New Key-Stream Generator Based on the OFB Mode of AES

Abstract

The key-stream generator is the most important algorithm component of the stream cipher and the security of the stream cipher is based on the property of the key-stream generator. At the present, it is still an important development direction of the stream cipher algorithm that the high performance key-stream generators are constructed with complex block cipher algorithms. This paper puts forward the new type of the key-stream generator based on the AES algorithm. This method is based on the OFB mode of the AES algorithm, combined with the variable-step feedback shift. Then the paper analyses the randomness of the key-stream produced by the new key-stream generator. This new key-stream generator really improves the cryptographic properties of the key stream generator and to enhance the security of stream cipher effectively.