41deg29'49" 71deg35'56" ZIP 02892 41.496944 71.598889 Roulette character set (38 characters) 'alphabet' is 0-9, a-z, upshift which is Pi (pronouned 'pie-pie'), and downshift which is a Cyrillic backwards 'R' (pronounced 'back-are'). random number 920342619 you@yours:~$ apg -a 1 -M N -m 9 check (add modulo 10) 9 "Key 4" is add 4 ("key fourteen" is subtract 4) zero is NOT allowed so 3 6 4 7 8 6 0 5 3 add to letter to ENcrypt, subtract to DEcrypt numbers > 9 are non-carrying just a nine-digit password vignere, not secure. t u v w x y z Pi bR 0 1 u v w x y z Pi bR 0 1 2 v w x y z Pi bR 0 1 2 3 w x y z Pi bR 0 1 2 3 in nine-character (password-sized) groups: s e n t t o u s p s w e s t k i n g s t o n r i 0 2 8 3 6 4 7 8 6 0 5 3 3 6 4 7 8 6 0 5 3 3 6 4 7 8 6 0 5 3 V K R Pi bR U U X S V C I Z bR Q I S J V Z S U Z O 0 7 A 9 2 z i p 4 1 2 9 4 9 n 7 1 3 5 5 6 w x a r r i v e a 3 6 4 7 8 6 5 0 3 3 6 4 7 8 6 5 0 3 3 6 4 7 8 6 5 0 3 C 8 1 P X A 6 2 C 7 F R E 9 9 A 5 9 Z 1 E Y Z O Pi E D t 1 1 l o c a l x b o k s c o d e Pi T A E 9 S I A K bR 3 6 4 7 8 6 5 0 3 3 6 4 7 8 6 5 0 3 3 6 4 7 8 6 5 0 3 W 7 5 S W I G L Pi E U O Z K U I E 1 W G I G Pi O F K 2 r p t Pi T A E 9 S I A K bR x v a l e r i e d a v i s x 3 6 4 7 8 6 5 0 3 3 6 4 7 8 6 5 0 3 3 6 4 7 8 6 5 0 3 U V X 5 bR G J 9 V L G O 6 3 bR F L H U O I K I bR N S Pi g o d s p e e d x y 2 4 7 3 6 4 7 8 6 5 0 3 3 6 4 7 J U G Z X K J D Pi Br 8 8 4 'XY' ends message numbers at end are ((key additive digit)^(key additive digit) - (key checksum)) or ((4)^(4) - (9)) A bR would stand in for a negative sign (minus sign). Split into 5-character groups for transmission. Add nulls at the end, as long as the first one is alpha not numeric. --- Later: This cipher system in general is called a Gronsfeld. A page for cracking Gronsfeld ciphers can be found at http://www.cs.trincoll.edu/~crypto/historical/gronsfeld.html or here as "part10b.htm"