Better Block Encryption (Here it is!)

[xcoder]

Now that is the style of Elon Musk. Never give up!
My code was not the best, but I am moving forward.

[xxgeek]

Feb 4, 2023 10:15:47 GMT xcoder said:

Now that is the style of Elon Musk. Never give up!
My code was not the best, but I am moving forward.

I have some bad news. I was fooled by my own code again. Your code was ok, however you had everything coded twice, and there was no need. As you will see I have removed half the functions. There was no need to use separate functions for encrypt and decrypt since they were both doing the exact same thing to the text sent to them.

The bad news - After checking my code again this morning, I realized I had left the code in that was getting the text from the file, and not what I was pasting into the editor so I cannot paste encrypted text into the editor and have it come back intact when decrypted, but that's not your codes fault . Well not exactly anyway. Rod is right I believe, and to have the encrypted text able to be decrypted when pasting into the editor you will have to stick to ASCII characters from 32 - 127. It has got to be the problem, I have done so many tests I don't believe it could be anything else BUT that, that's all that is left it COULD be.

The good news is we can send the encrypted text to a file, and then reintroduce it to the editor, even after closing the app. So we CAN use this in code, and we can use it between 2 different users by sending the file it creates.

Keep in mind this app 'as is' is just the app for testing and not the finished product yet.
We will need to save every A$() array to a file as well as the encrypted text, and the key used to create it and reunite them with each other to decrypt.
I believe I can do that, it will be a while though, I'm working on quite a few apps presently.

Here's the code that is working. Play with it.
If the encrypted file exists on startup, it copies to text editor and can be decrypted. If the file does not exist, you get an empty editor to paste any unencrypted text, ready for encryption.
There are buttons to copy text in editor, and one to delete the encrypted file to start fresh if desired.
    'Text Encryption
   'author = xcoder
   'Date Feb 2023
   'Purpose - To encrypt blocks of text, for example Just Basic Programs
   ' Just paste your code into the text editor and press encrypt /decrypt button
   'to decrypt, press the same button
   nomainwin
   global key$, two64
   two64 = 2^64
   dim A$(10)
   WindowWidth = 600 : WindowHeight = 400
   UpperLeftX=int((DisplayWidth-WindowWidth)/2)
   UpperLeftY=int((DisplayHeight-WindowHeight)/2)
   texteditor #main.text, 200, 20, 360, 320
   button #main.enc, "Encrypt", [encrypt], ul, 55, 115, 110, 25
   button #main.dec, "Decrypt", [decrypt], ul, 55, 155, 110, 25
   button #main.clearKey , "Clear Key", [clearKey], ul, 30, 75, 70, 20
   button #main.dec , "Clear Text", [clearText], ul, 110, 75, 70, 20
   button #main.refresh , "Delete Encrypted File", [refresh], ul, 40, 200, 135, 25
   button #main.copytext , "Copy Text", [copytext], ul, 350, 340, 60, 25
   textbox #main.key, 30, 45, 150, 20
   textbox #main.subkey1, 30, 270, 150, 20
   textbox #main.subkey2, 30, 320, 150, 20
   statictext #main.editor, "Type or Paste Text Here", 335, 5, 190, 15
   statictext #main.sk1T, "SubKey 1", 85, 255, 60, 15
   statictext #main.sk2T, "SubKey 2", 85, 305, 60, 15
   statictext #main.encKey, "Enter Encryption Key (HEX)", 55, 30, 110, 15
   Open "Encryptor by xcoder" for dialog as #main
   #main "trapclose [quit]"
   key$ = "9e3779b9a1b2c3d4" 'hex 8 bytes (64 bits) '- original code key value = 16 chars
   #main.key key$
   if fileExists(DefaultDir$, "key") then
       open "key" for binary as #1
       #main.text input$(#1, lof(#1));
       close #1
       #main.text "!origin 0 0"
   end if
   wait

[encrypt]
   if cript = 1 then [decrypt]
   #main.key "!contents? key$"
   data 8, 64, 16, 128, 0, 0, 0, 0
   for i = 1 to 8
       read alpha
       Sbox(i) = alpha ''single bit flip in each byte
   next i
   call subKey
   #main.text "!contents? text$"
   text$ = trim$(text$)
   redim A$(len(text$))
   alpha$ = txMain$(text$)
   alpha$ = trim$(alpha$)
   #main.text "!cls"
   cript = 1
   #main.text alpha$
   open "key" for binary as #1
   #1 alpha$
   close #1
   restore
   #main.text "!origin 0 0"
   wait

[decrypt]
   #main.key "!contents? key$"
       if cript = 0 then
   if fileExists(DefaultDir$, "key") then
       open "key" for binary as #1
       alpha$ = input$(#1, lof(#1))
       close #1
       else
'#############################################################################
 tooBADsoSAD = 1
'#main.text "!contents? alpha$"    'this doesn't work when pasting encrypted text, as expected.
'#############################################################################
end if
       redim A$(len(alpha$))
       open "array" for input as #1
       while eof(#1) = 0
       x = x + 1
           line input #1, line$
           A$(x) = line$
       wend
       close #1
   end if
   call subKey
       data 8, 64, 16, 128, 0, 0, 0, 0
   for i = 1 to 8
       read alpha
       Sbox(i) = alpha ''single bit flip in each byte
   next i
   alpha$ = trim$(alpha$)
   bravo$ = txMain$(alpha$)
   bravo$ = trim$(bravo$)
   #main.text "!cls"
   #main.text bravo$
   cript = 0
   restore
   #main.text "!origin 0 0"
   wait

[clearKey]
   #main.key ""
   wait

[clearText]
   #main.text "!cls"
   wait

[refresh]
   if fileExists(DefaultDir$, "key") then kill DefaultDir$;"\key"
   #main.text "!cls"
   wait

[copytext]
   #main.text "!selectall"
   #main.text "!copy"
   wait

[quit]
   close #main
   End

sub subKey
   num = hexDec(key$)
   alpha = leftRotate(num,1)
   hexKey1$ = decHex$(alpha)
   #main.subkey1 hexKey1$
   bravo = leftRotate(num,4)
   hexKey2$ = decHex$(bravo)
   #main.subkey2 hexKey2$
   x = 1
   for i = 1 to len(hexKey1$) step 2
       chunk$ = mid$(hexKey1$,i,2)
       byte = hexDec(chunk$)
       K1(x) = byte
   next i
   x = 1
   for i = 1 to len(hexKey2$)step 2
       chunk$ = mid$(hexKey2$,i,2)
       byte = hexDec(chunk$)
       K2(x) = byte
       x = x + 1
   next i
end sub

' rotates bits left n times
function leftRotate(num,times)
   num = num mod two64
   r = (num * 2^ times) mod two64
   l = int(num /(2^ (64 - times)))
   leftRotate = r + l
end function

function txMain$(text$)
   open "array" for output as #1
   x = 1
   for i = 1 to len(text$) step 8
       chunk$ = mid$(text$,i,8)
       y = len(chunk$)
       if y < 8 then chunk$ = chunk$ + addPad$(y)
       A$(x) = chunk$ '*********************
       #1 A$(x)
       outStr$ = outStr$ + txRound1$(chunk$) 'envoke the rounds of cipher
       x = x + 1 'number of text blocks
   next i
   close #1
   txMain$ = outStr$
end function

function addPad$(x) 'pads the final text block
   if x < 8 then
       dif = 8 - x
       for i = 1 to dif
           pad$ = pad$ + chr$(0)
       next i
   end if
   addPad$ = pad$
end function

function txRound1$(in$)
   sideL$ = right$(in$,4) 'swap left and right halfs of data block
   sideR$ = left$(in$,4)
   perm$ = sideL$ + sideR$
   for i = 1 to 4 'process index 1 to 4 of D (new right half of data block)
       byte = asc(mid$(perm$,i,1)) 'Feistel technique
       D(i) = byte
       Sum(i) = K1(i) xor D(i) xor Sbox(i) 'key  data then Sbox flips one bit
       char$ = char$ + chr$(Sum(i))
   next i
   swap$ = char$ + sideR$ 'combine processed half and plain half
   txRound1$ = txRound2$(swap$)
end function

function txRound2$(in$)
   sideL$ = right$(in$,4)
   sideR$ = left$(in$,4)
   perm$ = sideL$ + sideR$
   for i = 1 to 4
       byte = asc(mid$(perm$,i,1))
       D(i) = byte
       Sum(i) = K2(i) xor D(i) xor Sbox(i)
       char$ = char$ + chr$(Sum(i))
   next i
   swap$ = char$ + sideR$
   txRound2$ = swap$
end function

'function for checking file existence
function fileExists(path$, filename$)
   dim info$(0, 0)
   files path$, filename$, info$()
   fileExists = val(info$(0, 0)) 'non zero is true
end function


[xxgeek]

I forgot to mention that you can change the key if desired.
Just remember to use the same key when decrypting.

I've been brainstorming how to go about structuring the code for a final product. It depends on what it will be used for I guess. The use I am personally striving for is to use it in code to encrypt bas files on the fly. A filedialog to choose the file, and an editor to display the results or paste some text for encryption (dual use), with a listbox with the names of the "saved encrypted" files - when clicked unites the original key and the original A$() array with the selected Listing.
Also a textbox for the user to create a name for the file created when pasted text is used instead of a file.

One thought has me concerned though.
If the A$() array is copied 'and it is needed to decipher the original encrypted text' the unencrypted text is kind of there in the open and could be deciphered manually by any savvy tech type.

[xxgeek]

Feb 4, 2023 21:32:04 GMT xxgeek said:

One thought has me concerned though.
If the A$() array is copied 'and it is needed to decipher the original encrypted text' the unencrypted text is kind of there in the open and could be deciphered manually by any savvy tech type.

Wrong again, man I shouldn't post when I'm sleep deprived.

The A$() array is totally unreadable, as it should be.
I had done so many tests and read so many of the resulting saved A$() array files I thought that was the case because many of them showed much of the original code/text in each block, but when I see array files that ARE working properly the encrypted blocks ARE totally unreadable.

Sorry about my inability to think straight when overtired.

I am still baffled as to why 'pasting' encrypted text to an editor doesn't work, while moving data from an encrypted file to the editor does work. It just doesn't make any sense to me, even considering Rod's information on control characters being in a texteditor, because those "control character" are in the same text coming from the file.

Rod, I'm not saying you are wrong, and you may very well be right, but I need to prove it to myself.
I still think it could be my code not getting all the variables and I am still trying to prove it somehow works if I can get it right.