attack vt. 1.攻击 (opp. defend)。 2.非难,抨击。 3.着手,动手,投入。 4.(疾病)侵袭。 5.【化学】腐蚀。 We will not attack unless we are attacked; if we are attacked, we will certainly counter- attack。 人不犯我,我不犯人;人若犯我,我必犯人。 attack a task 动手工作。 attack a problem 着手解决问题。 Strong acids attack metals. 强酸对金属有腐蚀作用。 be attacked with (a disease) 害(病)。 n. 1.攻击 (opp. defense), 袭击。 2.抨击。 3.【航空】迎角,冲角,攻角。 4.着手,动手。 5.发作,发病。 6.(表演或竞赛中的)主动。 A- is the best defense. 进攻是最好的防御。 an attack formation 攻击队形。 have an attack of 为…所侵袭;害,患(病)。 make an attack on 攻击。 n. -er 攻击者。
In statistical attacks on ciphers the known frequency of various bigrams, in a given language, can be used in attempts to break the cipher 在对密码的统计攻击中,可用已知语言的各双字母组的频度来攻破密码。
In the part of image encryption, chaotic map based on kolmogorov flow is used to permute . changing the traditional stream-cipher, new chaotic pseudo-random sequence generator based on the theory of product cipher is presented to substitute the pixel . based on it, linear map to confuse the pixel is presented further, withstanding statistical attack 在图像加密方面,采用基于kolmogorovflows的混沌映射对图像进行置乱,对传统流加密进行改造,提出了基于乘积密码理论的新型混沌伪随机序列发生器完成象素的混淆,并在此基础上进一步采用线性映射对象素进行扩散以抵抗统计攻击。