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Author Topic: Encrypt/Decrypt v0.1  (Read 5136 times)

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Offline TempodiBasic

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Encrypt/Decrypt v0.1
« on: June 14, 2018, 05:56:49 pm »
Hi Guys

here a ASCII program that let to play just a little with cryptography. It shows several methods that are based on the single unique relation between  character before and after traslation...
Enjoy to crypt your message
* encrypt1 prova.bas (Filesize: 13.9 KB, Downloads: 311)
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Offline bplus

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Re: Encrypt/Decrypt v0.1
« Reply #1 on: June 16, 2018, 10:40:04 am »
Looks like simple substitution BUT! you change the substitution codes as you progress through the message. Correct?

Like ye ol Enigma machine?

Got to say, I don't understand menu and nothing stays up long enough for me to read it (I am slow with bad eyes, it's true.) and where is my coded message going?
« Last Edit: June 16, 2018, 10:52:09 am by bplus »
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Offline TempodiBasic

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Re: Encrypt/Decrypt v0.1
« Reply #2 on: June 16, 2018, 02:25:57 pm »
Hi Bplus
 Thank's to take a look at my encrypt/decrypt

Yes you are right,
 in this very early version of the program it has been coded the procedure that I have called Traslation, because getting together the avaible symbols to use for the message, we can build a ring (a linear sequence that restart itself) and we can code and decode shifting from original position to coded position and then backward .
The first and the second methods are a variable version of the Giulius Ceaser's cipher as can see at this webpage
 https://en.wikipedia.org/wiki/Caesar_cipher,  while the other methods also if they make a substitution one to one they use different aritmetic method to choose the final coded symbol.
So on other hand if we want call this procedure Substitution, we must say also one to one  in fact substitution one to one because we can also make a substitution one to many in so many manners....

Yes you are right also about time elapsed to read results of coding and decoding....
To give more time to read and let go on to the user that don't want spend all those seconds I must substituite _DELAY with SLEEP
and so I can rise the number of seconds from 2 to 6.
Moreover the output shows original message, result message both in coding both in decoding. And there is also a timestamp... (it is the same because QB64 is very fast!) and the number of characters of the message as checksum.

Here the new version 0.2 of Encrypt/Decrypt

Code: QB64: [Select]
  1. _TITLE "QB64 encrypt/decrypt 0.1"
  2. CONST MessageConst = "QB64 is the best evolution of QB4.5 and PDS 7.1 for multiplatform BASIC programming. Moreover Inform is a powerful tool to use hardly for our projects."
  3. CONST StepConst = 1, JumpConst = 0
  4. CONST ALPHAbeta = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789" '26 maiuscole + 26 minuscole + 10 cifre
  5.  
  6. DIM SHARED DecrMessage$
  9.  
  10. '-----------starting  help
  11. COLOR 31, 2
  12. _PRINTSTRING (6, 1), "CRYPTING/DECRYPTING METHODS"
  13. COLOR 15, 1
  14. _PRINTSTRING (6, 2), "Using linear correlation between character at start time and at end time"
  15. _PRINTSTRING (6, 3), "Each message has the same number of characters at the start and at the end"
  16. _PRINTSTRING (6, 5), "Press ESC to end, from 0 to 8 for choosing method, M S R J to set variables"
  17. COLOR 15, 0
  20. help
  21.  
  22. '-----------           setting to default the variables of crypting
  23. mesg$ = MessageConst
  24. steps% = 1 'how calculate next encrypted value
  25. seed% = 1 'starting value to encrytp
  26. jump% = 0 ' how many characters jump the coding
  27.  
  28. ' main loop
  30.     ' here user select method of encrypting to show
  31.     choice$ = INKEY$
  32.     IF LEN(choice$) > 0 AND choice$ <> CHR$(27) THEN ' do nothing but fix bug
  33.         CLS
  34.         SELECT CASE choice$
  35.             CASE "M", "m"
  36.                 ' modifying message to crypting
  37.                 INPUT "Please type the new message and then press Enter, hit only Enter to cancel:", mesg$
  38.                 IF LEN(mesg$) = 0 THEN mesg$ = MessageConst
  39.                 PRINT " you set this message "; mesg$
  40.             CASE "S", "s"
  41.                 'modifying step of codifing
  42.                 INPUT "Please type the number to encode the message: ", steps%
  43.                 IF steps% <= 0 THEN steps% = 1
  44.                 PRINT " you set this STEP"; steps%
  45.             CASE "R", "r"
  46.                 'radix or seed of starting to calculate
  47.                 INPUT "please type the number to start to coding: ", seed%
  48.                 IF seed% <= 0 THEN seed% = 1
  49.                 PRINT " you set this SEED/RADIX "; seed%
  50.             CASE "J", "j"
  51.                 ' jump the number of character of the message to code
  52.                 INPUT "Please type how many characters to jump (no code):", jump%
  53.                 PRINT " you set this JUMP (characters no coded) "; jump%
  54.             CASE "0"
  55.                 ' encryptfixForward
  56.                 encryptFixF mesg$, steps%, jump%
  57.                 encryptFixB DecrMessage$, steps%, jump%
  58.             CASE "1"
  59.                 'encryptfixBackward
  60.                 encryptFixB mesg$, steps%, jump%
  61.                 encryptFixF DecrMessage$, steps%, jump%
  62.             CASE "2"
  63.                 ' progressive linear method increasing (+) by 1-2-3-4 starting from seed%
  64.                 encryptProg mesg$, 1, steps%, seed%, jump%
  65.                 encryptProg DecrMessage$, 2, steps%, seed%, jump%
  66.             CASE "3"
  67.                 ' progressive linear method decreasing (-) by 1-2-3-4 from seed%
  68.                 encryptProg mesg$, 2, steps%, seed%, jump%
  69.                 encryptProg DecrMessage$, 1, steps%, seed%, jump%
  70.             CASE "4"
  71.                 ' progressive linear method  alternating +/- vs -/+ by 1-2-3-4 from seed%
  72.                 encryptProg mesg$, 3, steps%, seed%, jump%
  73.                 encryptProg DecrMessage$, 4, steps%, seed%, jump%
  74.             CASE "5"
  75.                 ' progressive linear method  alternating -/+ vs +/- by 1-2-3-4 from seed%
  76.                 encryptProg mesg$, 4, steps%, seed%, jump%
  77.                 encryptProg DecrMessage$, 3, steps%, seed%, jump%
  78.             CASE "6"
  79.                 ' progressive quadratic method increasing by 1^2 +seed%, 2^2 + seed%, 3^2+ seed%
  80.                 encryptProg mesg$, 5, steps%, seed%, jump%
  81.                 encryptProg DecrMessage$, 6, steps%, seed%, jump%
  82.             CASE "7"
  83.                 ' progressive quadratic method decreasing by 1^2 +seed%, 2^2 + seed%, 3^2+ seed%
  84.                 encryptProg mesg$, 6, steps%, seed%, jump%
  85.                 encryptProg DecrMessage$, 5, steps%, seed%, jump%
  86.             CASE "8"
  87.                 ' progressive quadratic method alternating +/- vs -/+ by 1^2 +seed%, 2^2 + seed%, 3^2+ seed%
  88.                 encryptProg mesg$, 7, steps%, seed%, jump%
  89.                 encryptProg DecrMessage$, 8, steps%, seed%, jump%
  90.             CASE "9"
  91.                 ' progressive quadratic method alternating -/+ vs +/- by 1^2 +seed%, 2^2 + seed%, 3^2+ seed%
  92.                 encryptProg mesg$, 8, steps%, seed%, jump%
  93.                 encryptProg DecrMessage$, 7, steps%, seed%, jump%
  94.  
  95.  
  96.             CASE ELSE
  97.                 ' here we manage exceptions
  98.                 PRINT "THIS CASE IS NOT YET CODED"
  99.         END SELECT
  100.         ' _DELAY 2
  101.         SLEEP 6
  102.         CLS
  103.         help
  104.     END IF
  105. LOOP UNTIL choice$ = CHR$(27)
  106.  
  107. END ' logic end of program
  108.  
  109. '-------------------area of SUBroutines and Functions
  110. SUB help
  111.     PRINT " 0 encryptfixForward"
  112.     PRINT " 1 encryptfixBackward"
  113.     PRINT " 2 progressive linear method increasing "
  114.     PRINT " 3 progressive linear method decreasing "
  115.     PRINT " 4 progressive linear method  alternating +/-"
  116.     PRINT " 5 progressive linear method  alternating  -/+"
  117.     PRINT " 6 progressive quadratic method increasing by n^2"
  118.     PRINT " 7 progressive quadratic method decreasing by n^2"
  119.     PRINT " 8 progressive quadratic method alternating +/- vs -/+ by n^2 "
  120.     PRINT " M to set message to crypting"
  121.     PRINT " S to set step of crypting"
  122.     PRINT " R to set radix of crypting"
  123.     PRINT " J to set how characters to jump"
  125.  
  126. SUB encryptProg (Messag$, step1%, steps%, seed%, jump%)
  127.     ' step1% chooses the method, step2% chooses the step of sequence to add to seed  , seed% is the starting value
  128.     msg$ = Messag$
  129.     MsgLen% = LEN(msg$)
  130.     DecrMessage$ = ""
  131.     step2% = steps%
  132.     b% = 0
  133.     c% = LEN(ALPHAbeta)
  134.     st1% = seed%
  135.     sign% = 1
  136.  
  137.     PRINT msg$, TIME$, MsgLen% 'before traslation
  138.  
  139.     SELECT CASE step1%
  140.         CASE 1 ' progressive linear method increasing (+) by 1-2-3-4 starting from seed%
  141.             FOR a% = 1 TO MsgLen% STEP 1
  142.                 ch$ = MID$(msg$, a%, 1)
  143.                 IF b% < jump% THEN
  144.                     b% = b% + 1
  145.                 ELSE
  146.                     IF INSTR(ALPHAbeta, ch$) > 0 THEN
  147.                         pos1% = INSTR(ALPHAbeta, ch$)
  148.                         st1% = st1% + step2% 'increasing the added factor
  149.                         step2% = step2% + 1 ' linear increasing sequence
  150.                         IF st1% > c% THEN st1% = st1% MOD c%
  151.                         IF (pos1% + st1%) > c% THEN pos1% = (pos1% + st1%) - c% ELSE pos1% = pos1% + st1%
  152.                         ch$ = MID$(ALPHAbeta, pos1%, 1)
  153.                     END IF
  154.                     b% = 0
  155.  
  156.                 END IF
  157.                 DecrMessage$ = DecrMessage$ + ch$
  158.             NEXT
  159.  
  160.             PRINT DecrMessage$, TIME$, LEN(DecrMessage$) 'after traslation
  161.  
  162.         CASE 2 ' progressive linear method decreasing (-) by 1-2-3-4 from seed%
  163.  
  164.             FOR a% = 1 TO MsgLen% STEP 1
  165.                 ch$ = MID$(msg$, a%, 1)
  166.                 IF b% < jump% THEN
  167.                     b% = b% + 1
  168.                 ELSE
  169.                     IF INSTR(ALPHAbeta, ch$) > 0 THEN
  170.                         pos1% = INSTR(ALPHAbeta, ch$)
  171.                         st1% = st1% + step2%
  172.                         step2% = step2% + 1 'increasing the added factor
  173.                         IF st1% > c% THEN st1% = st1% MOD c%
  174.                         IF (pos1% - st1%) < 1 THEN pos1% = (pos1% - st1%) + c% ELSE pos1% = pos1% - st1%
  175.                         ch$ = MID$(ALPHAbeta, pos1%, 1)
  176.                     END IF
  177.                     b% = 0
  178.                 END IF
  179.                 DecrMessage$ = DecrMessage$ + ch$
  180.             NEXT
  181.  
  182.             PRINT DecrMessage$, TIME$ 'after traslation
  183.  
  184.         CASE 3, 4 ' progressive linear method  alternating +/- vs -/+ by 1-2-3-4 from seed%
  185.             IF step1% = 4 THEN sign% = -1
  186.             FOR a% = 1 TO MsgLen% STEP 1
  187.                 ch$ = MID$(msg$, a%, 1)
  188.                 IF b% < jump% THEN
  189.                     b% = b% + 1
  190.                 ELSE
  191.                     IF INSTR(ALPHAbeta, ch$) > 0 THEN
  192.                         pos1% = INSTR(ALPHAbeta, ch$)
  193.                         st1% = st1% + step2%
  194.                         step2% = step2% + 1 'increasing the added factor
  195.                         IF st1% > c% THEN st1% = st1% MOD c%
  196.                         IF sign% = 1 THEN
  197.                             IF (pos1% + st1%) > c% THEN pos1% = (pos1% + st1%) - c% ELSE pos1% = pos1% + st1%
  198.                         ELSE
  199.                             IF (pos1% - st1%) < 1 THEN pos1% = (pos1% - st1%) + c% ELSE pos1% = pos1% - st1%
  200.                         END IF
  201.                         sign% = sign% * -1
  202.                         ch$ = MID$(ALPHAbeta, pos1%, 1)
  203.                     END IF
  204.                     b% = 0
  205.                 END IF
  206.                 DecrMessage$ = DecrMessage$ + ch$
  207.             NEXT
  208.  
  209.             PRINT DecrMessage$, TIME$ 'after traslation
  210.  
  211.         CASE 5 ' progressive quadratic method increasing by 1^2 +seed%, 2^2 + seed%, 3^2+ seed%
  212.             FOR a% = 1 TO MsgLen% STEP 1
  213.                 ch$ = MID$(msg$, a%, 1)
  214.                 IF b% < jump% THEN
  215.                     b% = b% + 1
  216.                 ELSE
  217.                     IF INSTR(ALPHAbeta, ch$) > 0 THEN
  218.                         pos1% = INSTR(ALPHAbeta, ch$)
  219.                         st1% = st1% + (step2% ^ 2) 'increasing the added factor
  220.                         step2% = step2% + 1 ' linear increasing sequence
  221.                         IF st1% > c% THEN st1% = st1% MOD c%
  222.                         IF (pos1% + st1%) > c% THEN pos1% = (pos1% + st1%) - c% ELSE pos1% = pos1% + st1%
  223.                         ch$ = MID$(ALPHAbeta, pos1%, 1)
  224.                     END IF
  225.                     b% = 0
  226.  
  227.                 END IF
  228.                 DecrMessage$ = DecrMessage$ + ch$
  229.             NEXT
  230.  
  231.             PRINT DecrMessage$, TIME$, LEN(DecrMessage$) 'after traslation
  232.  
  233.         CASE 6 ' progressive quadratic method decreasing by 1^2 +seed%, 2^2 + seed%, 3^2+ seed%
  234.  
  235.             FOR a% = 1 TO MsgLen% STEP 1
  236.                 ch$ = MID$(msg$, a%, 1)
  237.                 IF b% < jump% THEN
  238.                     b% = b% + 1
  239.                 ELSE
  240.                     IF INSTR(ALPHAbeta, ch$) > 0 THEN
  241.                         pos1% = INSTR(ALPHAbeta, ch$)
  242.                         st1% = st1% + step2% ^ 2
  243.                         step2% = step2% + 1 'increasing the added factor
  244.                         IF st1% > c% THEN st1% = st1% MOD c%
  245.                         IF (pos1% - st1%) < 1 THEN pos1% = (pos1% - st1%) + c% ELSE pos1% = pos1% - st1%
  246.                         ch$ = MID$(ALPHAbeta, pos1%, 1)
  247.                     END IF
  248.                     b% = 0
  249.                 END IF
  250.                 DecrMessage$ = DecrMessage$ + ch$
  251.             NEXT
  252.  
  253.             PRINT DecrMessage$, TIME$, LEN(DecrMessage$) 'after traslation
  254.  
  255.         CASE 7, 8 ' progressive quadratic method alternating +/- vs -/+ by 1^2 +seed%, 2^2 + seed%, 3^2+ seed%
  256.  
  257.             IF step1% = 8 THEN sign% = -1
  258.             FOR a% = 1 TO MsgLen% STEP 1
  259.                 ch$ = MID$(msg$, a%, 1)
  260.                 IF b% < jump% THEN
  261.                     b% = b% + 1
  262.                 ELSE
  263.                     IF INSTR(ALPHAbeta, ch$) > 0 THEN
  264.                         pos1% = INSTR(ALPHAbeta, ch$)
  265.                         st1% = st1% + step2%
  266.                         step2% = step2% + 1 'increasing the added factor
  267.                         IF st1% > c% THEN st1% = st1% MOD c%
  268.                         IF sign% = 1 THEN
  269.                             IF (pos1% + st1%) > c% THEN pos1% = (pos1% + st1%) - c% ELSE pos1% = pos1% + st1%
  270.                         ELSE
  271.                             IF (pos1% - st1%) < 1 THEN pos1% = (pos1% - st1%) + c% ELSE pos1% = pos1% - st1%
  272.                         END IF
  273.                         sign% = sign% * -1
  274.                         ch$ = MID$(ALPHAbeta, pos1%, 1)
  275.                     END IF
  276.                     b% = 0
  277.                 END IF
  278.                 DecrMessage$ = DecrMessage$ + ch$
  279.             NEXT
  280.  
  281.             PRINT DecrMessage$, TIME$, LEN(DecrMessage$) 'after traslation
  282.  
  283.  
  284.         CASE ELSE
  285.     END SELECT
  286.  
  288.  
  289. SUB encryptFixF (Messag$, step2%, jump%)
  290.     ' crypting fixed forward
  291.     msg$ = Messag$
  292.     IF step2% < 0 THEN step1% = -step2% ELSE step1% = step2%
  293.     MsgLen% = LEN(msg$)
  294.     DecrMessage$ = ""
  295.  
  296.     b% = 0
  297.     c% = LEN(ALPHAbeta)
  298.     PRINT msg$, TIME$, MsgLen% 'before traslation
  299.     FOR a% = 1 TO MsgLen% STEP 1
  300.         ch$ = MID$(msg$, a%, 1)
  301.         IF b% < jump% THEN
  302.             b% = b% + 1
  303.         ELSE
  304.             IF INSTR(ALPHAbeta, ch$) > 0 THEN
  305.                 pos1% = INSTR(ALPHAbeta, ch$)
  306.                 IF (pos1% + step1%) > c% THEN pos1% = (pos1% + step1%) - c% ELSE pos1% = pos1% + step1%
  307.                 ch$ = MID$(ALPHAbeta, pos1%, 1)
  308.             END IF
  309.             b% = 0
  310.         END IF
  311.         DecrMessage$ = DecrMessage$ + ch$
  312.     NEXT
  313.  
  314.     PRINT DecrMessage$, TIME$, MsgLen% 'after traslation
  316.  
  317. SUB encryptFixB (Messag$, step2%, jump%)
  318.     ' crypting fixed backward
  319.     msg$ = Messag$
  320.     IF step2% > 0 THEN step1% = -step2% ELSE step1% = step2%
  321.     MsgLen% = LEN(msg$)
  322.     DecrMessage$ = ""
  323.  
  324.     b% = 0
  325.     c% = LEN(ALPHAbeta)
  326.     PRINT msg$, TIME$, MsgLen% 'before traslation
  327.     FOR a% = 1 TO MsgLen% STEP 1
  328.         ch$ = MID$(msg$, a%, 1)
  329.         IF b% < jump% THEN
  330.             b% = b% + 1
  331.         ELSE
  332.  
  333.             IF INSTR(ALPHAbeta, ch$) > 0 THEN
  334.                 pos1% = INSTR(ALPHAbeta, ch$)
  335.                 IF (pos1% + step1%) < 1 THEN pos1% = (pos1% + step1%) + c% ELSE pos1% = pos1% + step1%
  336.                 ch$ = MID$(ALPHAbeta, pos1%, 1)
  337.             END IF
  338.             b% = 0
  339.         END IF
  340.         DecrMessage$ = DecrMessage$ + ch$
  341.     NEXT
  342.  
  343.     PRINT DecrMessage$, TIME$, MsgLen% 'after traslation
  345.  

STEP and RADIX/SEED affect the result of calculation, JUMP affect what character in the message will be encrypted, MESSAGE let choose a different message to translate.

It maybe interesting to code an engine to attack with brute force this encoder and to get original message without decoding...

Thank's for read and try
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