破解单字母替代加密

谢希仁版计算机网络本科教材倒数第二章的课后第一题

kfd   ktbd   fzm   eubd   kfd   pzyiom   mztx   ku   kzyg   ur   bzha   kfthcm  
  ur   mftnm   zhx   mfudm   zhx   mdzythc   pzq   ur   ezsszcdm   zhx   gthcm  
  zhx   pfa   kfd   mdz   tm   sutythc   fuk   zhx   pfdkfdi   ntcm   fzld   pthcm  
  sok   pztk   z   stk   kfd   uamkdim   eitdx   sdruid   pd   fzld   uoi   efzk  
  rui   mubd   ur   om   zid   uok   ur   sidzkf   zhx   zyy   ur   om   zid   rzk  
  hu   foiia   mztx   kfd   ezindhkdi   kfda   kfzhgdx   ftb   boef   rui   kfzk  

准备：单字母高频统计表

Frequencies of the letters in the English language           E     12.51% T 9.25 A 8.04 O 7.60 I 7.26 N 7.09 S 6.54 R 6.12 H 5.49 L 4.14 D 3.99 C 3.06 U 2.71 M 2.53 F 2.30 P 2.00 G 1.96 W 1.92 Y 1.73 B 1.54 V 0.99 K 0.67 X 0.19 J 0.16 Q 0.11 Z 0.09

The most common first letter in a word in order of frequency
          T, O, A, W, B, C, D, S, F, M, R, H, I, Y, E, G, L, N, O, U, J, K
The most common second letter in a word in order of frequency
          H, O, E, I, A, U, N, R, T
The most common third letter in a word in order of frequency
          E, S, A, R, N, I
The most common last letter in a word in order of frequency
          E, S, T, D, N, R, Y, F, L, O, G, H, A, K, M, P, U, W
More than half of all words end with
          E ,T, D, S
Letters most likely to follow E in order of frequency
          R,S,N,D
The most common digraphs on order of frequency
          TH, HE, AN, IN, ER, ON, RE, ED, ND, HA, AT, EN, ES, OF, NT, EA, TI, TO, IO, LE, IS, OU, AR, AS, DE, RT, VE
The most common trigraphs in order of frequency
          THE, AND, THA, ENT, ION, TIO, FOR, NDE, HAS, NCE, TIS, OFT, MEN
The most common double letters in order of frequency
          SS, EE, TT, FF, LL, MM, OO
The most common two-letter words in order of frequency
          of, to, in, it, is, be, as, at, so, we, he, by, or, on, do, if, me, my, up, an, go, no, us, am
The most common three-letter words in order of frequency
          the, and, for, are, but, not, you, all, any, can, had, her, was, one, our, out, day, get, has, him, his, how, man, new, now, old, see, two, way, who, boy, did, its, let, put, say, she, too, use
The most common four-letter words in order of frequency
          That, with, have, this, will, your, from, they, know, want, been, good, much, some, time, very, when, come, here, just, like, long, make, many, more, only, over, such, take, than, them, well, were
The most commonly used words in the English language in order of frequency
          The, of, and, to, in, a, is, that, be, it, by, are, for, was, as, he, with, on, his, at, which, but, from, has, this, will, one, have, not, were, or, all, their, an, I, there, been, many, more, so, when, had, may, today, who, would, time, we, about, after, dollars, if, my, other, some, them, being, its, no, only, over, very, you, into, most, than, they, day, even, made, out, first, great, must, these, can, days, every, found, general, her, here, last, new, now, people, public, said, since, still, such, through, under, up, war, well, where, while, years, before, between, country, debts, good, him, interest, large, like, make, our, take, upon, what

最高的是e用到的是a

第一轮

一眼扫过去.kfd  zhx kf组合  kfda里面 a是s或者y 统计z 27个.k 21个
而z是单字母.所以推测z=a

 

最后

明文表 t  h e a o u y r f b s i w ?(i)  l   n g m c p k x

密文表 k f d z u o a i  r s m t p ?(v) y  h c b  e n g q