Perl is very helpful for the programmer , but that can be an impediment when implementing bit - oriented algorithms Perl對程序員來說非常有用,但是它并不擅長處理面向比特的算法。
Obviously rc6 is not square - like cipher . square attack can only attack few rounds of rc6 , because the data - rotations of rc6 affact the rules of propagation for active and passive words , which makes square attack ineffective . we analyse the square attack against serpent which is bit - oriented cipher , and the result shows that square attack on serpent is weak , because the bit - oriented linear operations interrupt the rules of propagation for active and passive multiset 我們將square攻擊應用于rc6密碼,發現square攻擊只能攻擊少數幾輪rc6 ,這主要是因為rc6的數據依賴循環運算打亂了活動字節和固定字節的傳播路徑,使得攻擊無法進行。我們分析了對serpent密碼的square攻擊, serpent密碼的按比特線性混合運算打亂了所構造multiset的傳播路徑,使得攻擊只能進行到3輪serpent密碼。