Re: Seriation

Peter Fairbrother wrote:

Seriation is not a cipher, it is a technique used to build ciphers. Like
substitution and permutation, of which it is a form of the latter.
 
It can be useful eg with digram-based ciphers like Playfair, where it
makes cryptanalysis based on the known frequency of occurrence of
digrams in the plaintext language much harder or impossible.

Yes, thank you for the explanation! It could also be a nice replacement
for SCOS, here in sci.crypt, combined with an A-Z encoder/decoder and a
padding program, since SCOS was cracked and floating around on Bitmessage
and code for seriation I have not seen yet elsewhere.

As an example:

$ echo "I wish the sci.crypt community a nice weekend!" | pad -p 64 \
| az -l 16 > message.txt

$ cat message.txt

UJCQXHGZXDGYSAHU
WIGVSAHTWDGZSOGT
XCHZXAHUSAGTWPGN
WNHVWOGZXEHZSAGR
SAGOWJGTWFCQXHGV
WFGLWFGOWECRQKES
VJFXUJFSVKEOVEER
QJAQQAAQQAAQQAAQ

$ seriation < message.txt

UW JI CG QV XS HA GH ZT XW DD GG YZ SS AO HG UT
XW CN HH ZV XW AO HG UZ SX AE GH TZ WS PA GG NR
SW AF GG OL WW JF GG TO WW FE CC QR XQ HK GE VS
VQ JJ FA XQ UQ JA FA SQ VQ KA EA OQ VQ EA EA RQ

Maybe worth a little challenge, to have such a
format for sci.crypt, with an AZ encoder, a pad
and seriation program. :-)

--
Regards
Stefan

P.S. I have figured out the encryption/decrption
process for Doppelkastenschlüssel. :-) (Did not
had enough coffee ... :-D)