ASCII Modulated Vigenere Cipher with Sourcecode

This is largely an experimental program that uses the ASCII set of characters as the Vigenere square. It has considerable security but can’t ever be given theoretically unbreakable class because there is essentially an algorithm in there (for the finding) that can be found by cryptanalysts who are assumed to possess unlimited resources, unlike the change-of-origin ploy in vector cryptography that can never be reversed except by human intervention. This is a scalar cipher compared with a vector cipher and is classed as ‘symmetric’ within the cryptography industry.

The files that appear next are arranged automatically in alphabetical order by the computer software in the folder that exists and not in the order of calling by the main program at runtime or for any other reason. This is how they appear in the folder. They must however be ‘visible’ by the Ada-95 compiler that is stored in say – C:/programs/Gnat 3.11p/ or similar address.

Some files are related to each other and become packages in the Ada programming language e.g a smaller package ‘specification’ program denoted by the file extension (.ads) and a larger ‘body’ program denoted by the file extension (.adb). Such a pair of files forms a single package in the Ada-95 programs here. Other files that are not packages are called standalone pdf’s.

The main programs in the list of all programs below are evident from the titles having been written in capital letters. The main programs are also written in triplicate, mark_0, mark_1 and mark_2 for the following reasons.

1) ”Mark_0” is a special demonstration version of the main program in question that may serve as a tutorial program for first time users and is also useful as a diagnostic program if ever needed – that latter situation has not occurred to date.

2) “Mark_1” is a version of that same program that displays some output data but less than “Mark_0”.

3) “Mark_2” is the final working version that may display little or no any output.

There are six specimen files that can be used by the user (if you want to contact me) while becoming familiar with how the cipher works and after that the user will use the program cipher simply as a tool, writing real messages for emailing in the Ada GUI-IDE editor, firstly in plain English before carefully naming it appropriately, for calling by the cipher encryption program later on (just as it did with the specimen test programs). It is then called and encrypted into secret cipher-text during the runtime of the program. This cipher-text is then sent as an attachment file to an unsecured email covering letter.

How it all works is fully described in the preceding description notes that are already onboard the website but this may need some tracking down to find specific references.

The software source-code is written for compiling in an Ada-95 compiler. It is accepted by the writer that some readers may want to rewrite the program lines in a more cryptic form of the Ada programming language. That is in order for the time being provided there is no commercial gain from doing this. The software is copyright to the author. This is not free software by any definition of “free”. The cipher may also be copied verbatim and compiled by a Gnat 311.9 compiler for Ada-95 to produce a working program that has been well tested by the author.

Program titles (click on the links below to download)

1) CHARACTER_N_KEY_PILOT_PROGRAM.adb

2) Characters_Out.adb
3) Characters_Out.ads
Package ‘A’

4) Encryption_Pad_Characters.adb
5) Encryption_Pad_Characters.ads
Package ‘B’

6) KEYED_IN_ENCRYPTION_PROGRAM_mark_0.adb
7) KEYED_IN_ENCRYPTION_PROGRAM_mark_1.adb

8) Numbers_Out.adb
9) Numbers_Out.ads
Package ‘C’

10) TABLEAU_95_DECRYPTION_mark_0.adb
11) TABLEAU_95_DECRYPTION_mark_1.adb
12) TABLEAU_95_DECRYPTION_mark_2.adb

13) TABLEAU_95_ENCRYPTION_mark_0.adb
14) TABLEAU_95_ENCRYPTION_mark_1.adb
15) TABLEAU_95_ENCRYPTION_mark_2.adb

16) Tutorial_Encryption_Pad_Characters.adb
17) Tutorial_Encryption_Pad_Characters.ads
Package ‘D’

18) U_MAKE_ASCII_TEST_FILE.adb

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Feel free to print these pages or Click Here to download the PDF file.