Key Recovery Attack on Stream Cipher Grain v1 and Its Improvement
Juntao Gao · Journal of Southwest Jiaotong University · 2010
In order to probe into the security of the stream cipher Grain v1,three design weaknesses of the Grain v1 key-stream generator were pointed out by studying its structure.Based on the above work,a key recovery attack on the stream cipher Grain v1 with an intermediate state was proposed.Time complexity and memory complexity of the proposed attack are equal to the time complexity and memory complexity of the Grain v1 key-stream generator respectively.In order to resist the proposed attack,an improvement on the Grain v1 key-stream generator was made.The security analysis shows that the improved generator is secure against the proposed key recovery attack.