projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| d77d25ce | 1 | .\" Copyright (c) 1989, 1991 The Regents of the University of California. |
| 77fed4b3 TH |
2 | .\" All rights reserved. |
| 3 | .\" | |
| 91cff1e1 | 4 | .\" %sccs.include.redist.man% |
| 77fed4b3 | 5 | .\" |
| d77d25ce | 6 | .\" @(#)caesar.6 5.4 (Berkeley) %G% |
| 77fed4b3 | 7 | .\" |
| d77d25ce CL |
8 | .Dd |
| 9 | .Dt CAESAR 6 | |
| 10 | .Os | |
| 11 | .Sh NAME | |
| 12 | .Nm caesar | |
| 13 | .Nd decrypt caesar cyphers | |
| 14 | .Sh SYNOPSIS | |
| 15 | .Nm caesar | |
| 16 | .Op Ar rotation | |
| 17 | .Sh DESCRIPTION | |
| 77fed4b3 | 18 | The |
| d77d25ce | 19 | Nm caesar |
| 3f26f967 | 20 | utility attempts to decrypt caesar cyphers using English letter frequency |
| 77fed4b3 | 21 | statistics. |
| d77d25ce | 22 | Nm Caesar |
| 77fed4b3 | 23 | reads from the standard input and writes to the standard output. |
| d77d25ce | 24 | .Pp |
| 77fed4b3 | 25 | The optional numerical argument |
| d77d25ce | 26 | Ar rotation |
| 77fed4b3 | 27 | may be used to specify a specific rotation value. |
| d77d25ce | 28 | .Pp |
| 3f26f967 | 29 | The frequency (from most common to least) of English letters is as follows: |
| d77d25ce CL |
30 | .Pp |
| 31 | .Bd -filled -offset indent | |
| 3f26f967 | 32 | ETAONRISHDLFCMUGPYWBVKXJQZ |
| d77d25ce CL |
33 | .Ed |
| 34 | .Pp | |
| 3f26f967 | 35 | Their frequencies as a percentage are as follows: |
| d77d25ce CL |
36 | .Pp |
| 37 | .Bd -filled -offset indent | |
| 3f26f967 | 38 | E(13), T(10.5), A(8.1), O(7.9), N(7.1), R(6.8), I(6.3), S(6.1), H(5.2), |
| d77d25ce CL |
39 | D(3.8), L(3.4), F(2.9), C(2.7), M(2.5), U(2.4), G(2), |
| 40 | P(1.9), Y(1.9), | |
| 3f26f967 | 41 | W(1.5), B(1.4), V(.9), K(.4), X(.15), J(.13), Q(.11), Z(.07). |
| d77d25ce CL |
42 | .Ed |
| 43 | .Pp | |
| 44 | Rotated postings to | |
| 45 | .Tn USENET | |
| 46 | and some of the databases used by the | |
| 47 | .Xr fortune 6 | |
| 3f26f967 | 48 | program are rotated by 13 characters. |