高级数据加密标准 AES算法 清华 教学ppt

高级数据加密标准 AES算法 教学pptAES History年公开征集数据加密算法以取代年,共收到个算法年,从个中选中个算法:和年月:获胜,和年月:公布新的数据加密标准高级数据加密标准分组密码分组长度比特种不同长度的密钥和轮数比特密钥比特密钥比特密钥轮轮轮AES应用AES免费使用简单漂亮的设计安全性高实现效率高美国国家标准AES-128用于 SECRET信息AES-192和AES-256用于 TOP SECRET信息商业应用算法:状态与消息分组相同,个字节表示成乘的矩阵input bitesState ar7'ayoutput bites7101418712so0s01s0.2s0.3outo outa outs out127111511913S101.21.3cutouts out out13→→76710142.0S21S22S2outy outo out1oout14713117171|1153.0|53.1S3.2S3.3outs out7 out11lout15AES算法:总体State= plaintextAdd RoundKey(State, KeyoForⅰ=0tor-1000.1“0.20,3Sub Bytes stateShiftRows(state)101112MixColumns Stater-1202,n222,3Add Round Key(state, RoundKeyEnd forS3.053132|S3SubBytes(state)ShiftRows(State)- Mix Columns(State最后轮Add RoundKey state, RoundKeyCiphertext=State需要r+1个轮密钥AES: Sub BytesState= plaintextAddRoundKey(state, Key)Forⅰ=0tor-1Sub Bytes( State)ShiftRows(StateMixColumns StateAdd Round Key(state, RoundKeyEnd forSub Bytes(State)ShiftS。Ws( StateMix Columns(State)AddRoundKey state, RoundKeyCiphertext=StateAES: Sub Bytes字节代替变换( SubBytesl()∷对每个字节进行S盒查表代换SBox门nn1L.021.3P.20212.223202.1222330S31S:2S3330S31s32S33续比特输入、比特输出、可逆由以下两个步骤计算在中求=ˉ使用扩展算法)对应用以下仿射变换10