CODES and codebreaking
MONO-ALPHABETIC substitution detection
Makes a histographic display of the text letters. so, if a mono-alphabetic substitution has taken place,
the predominant characters will appear to the left of the histogram.
(NOTE: Makes and Uses HTML5 canvas).
Usage: save awk program as freq_bars.awk,
LINK to: LETTER FREQUENCY generator AWK program sorce code
Create text file of monoalphabetic text: input.txt
Then run in MAC terminal, UNIX/LINIX shell:
awk -f freq_bars.awk < input.txt > output.html
then click on output.html.
Monoalphabetic texts will show a proponderance of higher counts to the left .
Polyalpahbetic or non ENGLISH/GREMAN/FRENCH texts will have a different pattern.
One-Time-Pad Encrytpion system
- Deletes all word spaces.
- Adds a pre and postamble.
- Adds ASCII character of a text to the ASCII charcter number of another text, then deducts 100 from the number.
- Final task: Letter position transposition on all characters.
The addative cypher is generaly assumed by cryptography experts to be essentialy unbreakable, becasue
The user supplies and distribute their own addative-text keys. Addative text need to be at least as long as the message,
not randomly generated, as all known random-number generators are based on not-really-random algorithims.
- The key is not generated or re-cycled.
- The key is as long as the message.
- Possible candidate substitute character are ambigious. Any substitution produces infinite possibilites of the plaintext.
- Word spaces are removed, so any kind of word analysis is impossible.
- Security of the cypher depends on the management of the private text keys and their distribution and storage
As an alternative to distributiong key tests, daily news texts published by third parties can be used,
as long as they are NOT RE-USED. Security in this case is dependant on maintaining secrecy of which documents are being used as keys.
Recmmended user actions to maintian security.
- System manager to supply key texts.
- Cypher machine passworded.
- Key text(s) placed on air-gapped decrytping machine (never been, not capable of being networked).
- 57+ cycle deletion programs recommened to erase kesy and messages from all user machinery
- Hard drives returned to company for physical destruction after use.
- Extent of key selection would depend on the length of time the message is important. Lower security on key
selection (Commerical web-texts), could be permitted when the messages is valueless after s specific time, as message breaking might be possible if
some guess as to the key text could be made.
Computer-Aided Design Projects
Hardware repair notes