ARC4 Style Stream Encryptor with GUI

[xcoder]

global key$, key2$

'Text Encryption ARC4 stream cipher

'author = xcoder

' Just paste text into the texteditor and press encrypt button

'Uses hexidecimal Text Format that is Word Processor and Email compatible

nomainwin

global key$, key2$

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, 155, 110, 25

button #main.dec, "Decrypt", [decrypt], ul, 55, 195, 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, 240, 135, 25

button #main.copytext , "Copy Text", [copytext], ul, 75, 105, 60, 25

textbox #main.key, 30, 45, 150, 20

statictext #main.editor, "Type or Paste Text Here", 335, 5, 190, 15

statictext #main.encKey, "Encryption Key (Hex Characters)", 20, 30, 170, 15

Open "ARC4 Type Stream Encryptor " for window as #main

#main "trapclose [quit]"



key$ = "9e3779b9a1b2c3d4" ''' default key if none entered

prompt "Enter hexcidecimal Key"; key$ '''any number of hex characters

#main.key key$

#main.text "!autoresize"

if fileExists(DefaultDir$, "textEditor") then

open "textEditor" for input as #1

#main.text , text$ 'read from textEditor

close #1

#main.text "!origin 0 0" 'reset cursor

end if

wait



[encrypt]

if cript = 1 then [decrypt]

#main.key "!contents? key$"



if key$ = "" then [advise]

#main.text "!contents? text$" ' read from textEditor

call hexKey$

call KSA

alpha$ = txPRGA$(text$) '***** encrypt

#main.text "!cls"

cript = 1

#main.text alpha$ 'write to textEditor

open "textEditor" for output as #1

#1 alpha$

close #1

#main.text "!origin 0 0" 'reset cursor

wait



[decrypt]

#main.key "!contents? key$"

if key$ = "" then [advise]

#main.text "!contents? text$" 'read from textEditor

call hexKey$

call KSA

bravo$ = hex2Text$(text$) '***** decrypt

#main.text "!cls"

cript = 0

#main.text bravo$ 'write to textEditor

open "textEditor"for output as #1

#1 bravo$

close #1

#main.text "!origin 0 0" 'reset cursor



wait

[clearKey]

#main.key ""

wait

[clearText]

#main.text "!cls"

wait

[refresh]

if fileExists(DefaultDir$, "textEditor") then kill DefaultDir$;"\textEditor"

#main.text "!cls"

wait

[copytext]

#main.text "!selectall"

#main.text "!copy"

wait

[quit]

close #main

End

[advise]

notice "Key is required"

close #main

End



print "------------------------------------------------------------------------------------------------------------"



'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



sub hexKey$

print "Hex" + space$(5) + "Decimal"

for i = 1 to len(key$)step 2

chunk$ = mid$(key$,i,2)

byte = hexDec(chunk$)

key2$ = key2$ + chr$(byte)

print chunk$, byte

next i

print key2$

end sub



sub KSA '''''key expansion ^^^^^^^^^^^

dim S(256)

dim K(256)

i = 0

j = 0

for i = 0 to 255

S(i)= i

next i

for i = 0 to 255

K(i)= asc(mid$(key2$,i mod len(key2$)+1))

next i

for i = 0 to 255

j = (j+ S(i)+ K(i))mod 256

temp = S(i)

S(i)= S(j)

S(j)= temp

next i

end sub



print "############## Encryption Functions ##################"



function txPRGA$(inString$) '''''psuedo random byte generator

i = 0

j = 0

for x = 1 to len(inString$)

i = (i + 1) mod 256 '********

byte = asc(mid$(inString$,x,1))

j = (j + S(i))mod 256

temp = S(i)

S(i) = S(j)

S(j) = temp

St = (S(i) + S(j))mod 256

k = byte xor St

char$ = char$ + chr$(k)

next x

txPRGA$ = text2Hex$(char$)

end function



function text2Hex$(cipher$)

for i = 1 to len(cipher$) 'encrypted text

byte = asc(mid$(cipher$,i,1)) 'encrypted ascii

hex$ = decHex$(byte)

hex$ = right$("0" + hex$,2)

max$ = max$ + hex$ 'encrypted hex

next i

text2Hex$ = max$

end function



print "############# Decryption functions ###############"



function hex2Text$(hex$)

for i = 1 to len(hex$)step 2 'encrypted hex

chunk$ = mid$(hex$,i,2)

byte = hexDec(chunk$) 'encrypted ascii

text$ = text$ + chr$(byte) 'encrypted text

next i

hex2Text$= rxPRGA$(text$)

end function



function rxPRGA$(inString$) '''^^^^psuedo random byte generator

i = 0

j = 0

for x = 1 to len(inString$)

i = (i + 1) mod 256 '**********

byte = asc(mid$(inString$,x,1))

j = (j + S(i))mod 256

temp = S(i)

S(i) = S(j)

S(j) = temp

St = (S(i) + S(j))mod 256

k = byte xor St

char$ = char$ + chr$(k)

next x

rxPRGA$ = char$

end function

[xxgeek]

xcoder, the resulting encrypted text was adding a character at the end.

By trimming the text coming from the texteditor before encrypting, and before decrypting it has fixed the issue.

Seems to be working well, and I like this method of encryption. When I try changing one or 2 characters in the key, the resulting encrypted text remains very unreadable. Previous versions have given away some of the original text in the results.



   'Text Encryption ARC4 stream cipher
   'author = xcoder
   ' Just paste text into the texteditor and press encrypt button
   'Uses hexidecimal Text Format that is Word Processor and Email compatible


   nomainwin
   global key$, key2$
   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, 155, 110, 25
   button #main.dec, "Decrypt", [decrypt], ul, 55, 195, 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, 240, 135, 25
   button #main.copytext , "Copy Text", [copytext], ul, 75, 105, 60, 25
   textbox #main.key, 30, 45, 150, 20
   statictext #main.editor, "Type or Paste Text Here", 335, 5, 190, 15
   statictext #main.encKey, "Encryption Key (Hex Characters)", 20, 30, 170, 15
   Open "ARC4 Type Stream Encryptor " for window as #main
   #main "trapclose [quit]"
   key$ = "9e3779b9a1b2c3d4" ''' default key if none entered
   prompt "Enter hexcidecimal Key"; key$ '''any number of hex characters
   #main.key key$
   #main.text "!autoresize"
   if fileExists(DefaultDir$, "textEditor") then
       open "textEditor" for input as #1
       #main.text , text$ 'read from textEditor
       close #1
       #main.text "!origin 0 0" 'reset cursor
   end if
   wait

[encrypt]
   if cript = 1 then [decrypt]
   #main.key "!contents? key$"
   if key$ = "" then [advise]
   #main.text "!contents? text$" ' read from textEditor
   text$=trim$(text$)  '...............Added by xxgeek
   call hexKey$
   call KSA
   alpha$ = txPRGA$(text$) '***** encrypt
   #main.text "!cls"
   cript = 1
   #main.text alpha$ 'write to textEditor
   open "textEditor" for output as #1
   #1 alpha$
   close #1
   #main.text "!origin 0 0" 'reset cursor
   wait

[decrypt]
   #main.key "!contents? key$"
   if key$ = "" then [advise]
   #main.text "!contents? text$" 'read from textEditor
   text$=trim$(text$)  '...........ADDED by xxgeek
   call hexKey$
   call KSA
   bravo$ = hex2Text$(text$) '***** decrypt
   #main.text "!cls"
   cript = 0
   #main.text bravo$ 'write to textEditor
   open "textEditor"for output as #1
   #1 bravo$
   close #1
   #main.text "!origin 0 0" 'reset cursor
   wait

[clearKey]
   #main.key ""
   wait

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

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

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

[quit]
   close #main
   End

[advise]
   notice "Key is required"
   close #main
   End

   print "------------------------------------------------------------------------------------------------------------"

   '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

sub hexKey$
   print "Hex" + space$(5) + "Decimal"
   for i = 1 to len(key$)step 2
       chunk$ = mid$(key$,i,2)
       byte = hexDec(chunk$)
       key2$ = key2$ + chr$(byte)
       print chunk$, byte
   next i
   print key2$
end sub

sub KSA '''''key expansion ^^^^^^^^^^^
   dim S(256)
   dim K(256)
   i = 0
   j = 0
   for i = 0 to 255
       S(i)= i
   next i
   for i = 0 to 255
       K(i)= asc(mid$(key2$,i mod len(key2$)+1))
   next i
   for i = 0 to 255
       j = (j+ S(i)+ K(i))mod 256
       temp = S(i)
       S(i)= S(j)
       S(j)= temp
   next i
end sub

print "############## Encryption Functions ##################"

function txPRGA$(inString$) '''''psuedo random byte generator
   i = 0
   j = 0
   for x = 1 to len(inString$)
       i = (i + 1) mod 256 '********
       byte = asc(mid$(inString$,x,1))
       j = (j + S(i))mod 256
       temp = S(i)
       S(i) = S(j)
       S(j) = temp
       St = (S(i) + S(j))mod 256
       k = byte xor St
       char$ = char$ + chr$(k)
   next x
   txPRGA$ = text2Hex$(char$)
end function

function text2Hex$(cipher$)
   for i = 1 to len(cipher$) 'encrypted text
       byte = asc(mid$(cipher$,i,1)) 'encrypted ascii
       hex$ = decHex$(byte)
       hex$ = right$("0" + hex$,2)
       max$ = max$ + hex$ 'encrypted hex
   next i
   text2Hex$ = max$
end function

print "############# Decryption functions ###############"

function hex2Text$(hex$)
   for i = 1 to len(hex$)step 2 'encrypted hex
       chunk$ = mid$(hex$,i,2)
       byte = hexDec(chunk$) 'encrypted ascii
       text$ = text$ + chr$(byte) 'encrypted text
   next i
   hex2Text$= rxPRGA$(text$)
end function

function rxPRGA$(inString$) '''^^^^psuedo random byte generator
   i = 0
   j = 0
   for x = 1 to len(inString$)
       i = (i + 1) mod 256 '**********
       byte = asc(mid$(inString$,x,1))
       j = (j + S(i))mod 256
       temp = S(i)
       S(i) = S(j)
       S(j) = temp
       St = (S(i) + S(j))mod 256
       k = byte xor St
       char$ = char$ + chr$(k)
   next x
   rxPRGA$ = char$
end function
'


[xxgeek]

I've been trying to put together a useful application that uses your encryption code xcoder. This is what I have so far, but I'm not sure what else it needs, although I feel it needs "something'

Any ideas?
Play around with the code and let me know if there are any problems you notice.

   'Text Encryption
   'author = xcoder
   'Date Feb 2023
   'Purpose - To encrypt blocks of text, for example > Just Basic Programs
   nomainwin
   global key$, key2$
   keyLength$(1) = "8"
   keyLength$(2) = "12"
   keyLength$(3) = "16"
   keyLength$(4) = "24"
   keyLength$(5) = "32"
   keyLength$(6) = "48"
   keyLength$(7) = "64"
   keyLength$(8) = "96"
   keyLength$(9) = "128"
   WindowWidth = 900 : WindowHeight = 500
   UpperLeftX=int((DisplayWidth-WindowWidth)/2)
   UpperLeftY=int((DisplayHeight-WindowHeight)/2)
   menu #main,"File" , "Open File", [openFile], "Save As ", [saveAs], "Exit Program", [quit]
   texteditor #main.text, 210, 70, 670, 375
   texteditor #main.hiddenText, 0, 0, 0, 0
   combobox #main.keyLength, keyLength$(), [keyLength], 190, 0, 55, 25
   button #main.generate, "Generate Random Key", [generate], ul, 10, 0, 130, 23
   button #main.defkey, "Use Default  Key", [defKey], ul, 260, 0, 120, 23
   button #main.enc, "Encrypt Text", [encrypt], ul, 55, 270, 90, 45
   button #main.dec, "Decrypt Text", [decrypt], ul, 55, 325, 90, 45
   button #main.copykey, "Copy Key", [copyKey], ul, 10, 125, 70, 20
   button #main.clearKey , "Clear Key", [clearKey], ul, 10, 95, 70, 20
   button #main.dec , "Clear Text", [clearText], ul, 125, 95, 70, 20
   button #main.copytext , "Copy Text", [copytext], ul, 125, 125, 70, 20
   button #main.open , "Open File", [openFile], ul, 65, 220, 70, 30
   button #main.saveas , "Save Text", [saveAs], ul, 125, 160, 70, 30
   button #main.saveKey , "Save Key", [saveKey], ul, 10, 160, 70, 30
   textbox #main.key, 80, 30, 810, 20
   statictext #main.length, "Length", 145, 5, 35, 20
   statictext #main.editor, "Type or Paste Text Below", 370, 55, 190, 15
   statictext #main.encKey, "  Default Key", 8, 35, 70, 15
   statictext #main.lines, "", 700, 55, 150, 15
   Open "Encryptor      -      by xcoder" for window as #main
   #main "trapclose [quit]"
   defKey$ = "9e3779b9a1b2c3d4" ''' default key if none entered
   prompt "Enter hexcidecimal Key"; defKey$ '''any number of hex characters
   #main.key key$
   #main.text "!autoresize"
   if fileExists(DefaultDir$, "textEditor") then
       open "textEditor" for input as #1
       #main.text , text$ 'read from textEditor
       close #1
       #main.text "!origin 0 0" 'reset cursor
   end if
   length = 16 'initial default key length
   key$ = defKey$
   #main.key defKey$
   #main.text "!autoresize"
   #main.keyLength "select 16"
   wait

[defKey]
  #main.key defKey$
  #main.encKey "  Default Key"
  wait

[keyLength]
   #main.keyLength "selection? length$"
   length = val(length$)
   wait

[encrypt]
   if cript = 1 then [decrypt]
   #main.key "!contents? key$"
   if key$ = "" then [advise]
   #main.text "!contents? text$" ' read from textEditor
   text$=trim$(text$)  '...............Added by xxgeek
   call hexKey$
   call KSA
   alpha$ = txPRGA$(text$) '***** encrypt
   #main.text "!cls"
   cript = 1
   #main.text alpha$ 'write to textEditor
   open "textEditor" for output as #1
   #1 alpha$
   close #1
   #main.text "!origin 0 0" 'reset cursor
   wait

[decrypt]
   #main.key "!contents? key$"
   if key$ = "" then [advise]
   #main.text "!contents? text$" 'read from textEditor
   text$=trim$(text$)  '...........ADDED by xxgeek
   call hexKey$
   call KSA
   bravo$ = hex2Text$(text$) '***** decrypt
   #main.text "!cls"
   cript = 0
   #main.text bravo$ 'write to textEditor
   open "textEditor"for output as #1
   #1 bravo$
   close #1
   #main.text "!origin 0 0" 'reset cursor
   wait

[generate]
   #main.encKey "Random Key"
   key$ = "" : #main.key "!selectall" : #main.key ""
   keyCharStr$ = "0 1 2 3 4 5 6 7 8 9 a b c d e f A B C D E F"
   for x = 1 to length
       intNum = int(rnd(1)*22)+1
       hexNum$ = word$(keyCharStr$, intNum)
       key$ = key$;hexNum$
   next x
   #main.key key$
   wait

[openFile]
   #main.text "!cls"
   filedialog "Open \ Select a File", DefaultDir$; "\*.enc;*.key;*.txt;*.bas", openFilename$
   if openFilename$ = "" then wait
   open openFilename$ for input as #1
   text$ = input$(#1,lof(#1))
   if right$(openFilename$, 4) = ".key" then #main.key text$ else #main.text text$
   close #1
   #main.text "!lines numLines";
   #main.lines numLines;" Lines "
   #main.text "!origin 0 0"
   wait

[saveAs]
   #main.text "!contents? text$"
   filedialog "Save As...", "*.enc", fileName$
   if fileName$ = "" then wait
   open fileName$ for output as #1
   #1 text$
   close #1
   wait

[saveKey]
   #main.key "!contents? key$"
   filedialog "Save As...", "*.key", fileName$
   if fileName$ = "" then wait
   open fileName$ for output as #1
   #1 key$
   close #1
   wait

[clearKey]
   #main.key ""
   wait

[clearText]
   #main.text "!cls"
   cript = 0
   wait

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

[copyKey]
   #main.key "!contents? key$"
   #main.hiddenText key$
   #main.hiddenText "!selectall"
   #main.hiddenText "!copy"
   #main.hiddenText  "!cls"
   wait

[quit]
   close #main
   End


   '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

sub hexKey$
   print "Hex" + space$(5) + "Decimal"
   for i = 1 to len(key$)step 2
       chunk$ = mid$(key$,i,2)
       byte = hexDec(chunk$)
       key2$ = key2$ + chr$(byte)
       print chunk$, byte
   next i
   print key2$
end sub

sub KSA '''''key expansion ^^^^^^^^^^^
   dim S(256)
   dim K(256)
   i = 0
   j = 0
   for i = 0 to 255
       S(i)= i
   next i
   for i = 0 to 255
       K(i)= asc(mid$(key2$,i mod len(key2$)+1))
   next i
   for i = 0 to 255
       j = (j+ S(i)+ K(i))mod 256
       temp = S(i)
       S(i)= S(j)
       S(j)= temp
   next i
end sub

print "############## Encryption Functions ##################"

function txPRGA$(inString$) '''''psuedo random byte generator
   i = 0
   j = 0
   for x = 1 to len(inString$)
       i = (i + 1) mod 256 '********
       byte = asc(mid$(inString$,x,1))
       j = (j + S(i))mod 256
       temp = S(i)
       S(i) = S(j)
       S(j) = temp
       St = (S(i) + S(j))mod 256
       k = byte xor St
       char$ = char$ + chr$(k)
   next x
   txPRGA$ = text2Hex$(char$)
end function

function text2Hex$(cipher$)
   for i = 1 to len(cipher$) 'encrypted text
       byte = asc(mid$(cipher$,i,1)) 'encrypted ascii
       hex$ = decHex$(byte)
       hex$ = right$("0" + hex$,2)
       max$ = max$ + hex$ 'encrypted hex
   next i
   text2Hex$ = max$
end function

print "############# Decryption functions ###############"

function hex2Text$(hex$)
   for i = 1 to len(hex$)step 2 'encrypted hex
       chunk$ = mid$(hex$,i,2)
       byte = hexDec(chunk$) 'encrypted ascii
       text$ = text$ + chr$(byte) 'encrypted text
   next i
   hex2Text$= rxPRGA$(text$)
end function

function rxPRGA$(inString$) '''^^^^psuedo random byte generator
   i = 0
   j = 0
   for x = 1 to len(inString$)
       i = (i + 1) mod 256 '**********
       byte = asc(mid$(inString$,x,1))
       j = (j + S(i))mod 256
       temp = S(i)
       S(i) = S(j)
       S(j) = temp
       St = (S(i) + S(j))mod 256
       k = byte xor St
       char$ = char$ + chr$(k)
   next x
   rxPRGA$ = char$
end function
'


[xcoder]

Thanks for the tip about trimming text. concerning generating random keys, see my post titled
"Key Generator."
One thing I must bring to everyone's attention is that this code will encrypt when using text characters as the key. However this creates extremely weak encryption and functions more like a simple XOR scrambler.
For example:
key: hello
The hex character (e) functions as a key.
If there are multiple hex characters in the text, then only the final hex character functions as
the key. for example:
key: hello world
The final hex character (d) functions as the key.

If there are no hex characters, then zero(0) functions as the key. For strong encryption, use hex
characters as the key.
By the way, this code is an approximation of the famous RC4 cipher explained on wikipedia.

[xcoder]

'Text Encryption ARC4 stream cipher
'author = xcoder
' This version allows use of plain text pass words as the "Key" ^^^^^^^^^^^^
' Just paste text into the texteditor and press encrypt button
'Uses hexidecimal Text Format that is Word Processor and Email compatible
nomainwin
global key$, key2$
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, 155, 110, 25
button #main.dec, "Decrypt", [decrypt], ul, 55, 195, 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, 240, 135, 25
button #main.copytext , "Copy Text", [copytext], ul, 75, 105, 60, 25
textbox #main.key, 30, 45, 150, 20
statictext #main.editor, "Type or Paste Text Here", 335, 5, 190, 15
statictext #main.encKey, "Encryption Key ", 20, 30, 170, 15
Open "ARC4 Type Stream Encryptor " for window as #main
#main "trapclose [quit]"

key$ = "MyFavoritePassWord" ''' default key if none entered
prompt "Enter a Password"; key$ '''any number of hex characters
#main.key key$
#main.text "!autoresize"
if fileExists(DefaultDir$, "textEditor") then
open "textEditor" for input as #1
#main.text , text$ 'read from textEditor
close #1
#main.text "!origin 0 0" 'reset cursor
end if

wait
[encrypt]
if cript = 1 then [decrypt]
#main.key "!contents? key$"
if key$ = "" then [advise]
#main.text "!contents? text$" ' read from textEditor
text$ = trim$(text$)
call keyPass '''^^^^^^^^^^^^^ modified
call KSA
alpha$ = txPRGA$(text$) '***** encrypt
#main.text "!cls"
cript = 1
#main.text alpha$ 'write to textEditor
open "textEditor" for output as #1
#1 alpha$
close #1
#main.text "!origin 0 0" 'reset cursor

wait
[decrypt]
#main.key "!contents? key$"
if key$ = "" then [advise]
#main.text "!contents? text$" 'read from textEditor
text$ = trim$(text$)
call keyPass '''^^^^^^ modified
call KSA
bravo$ = hex2Text$(text$) '***** decrypt
#main.text "!cls"
cript = 0
#main.text bravo$ 'write to textEditor
open "textEditor"for output as #1
#1 bravo$
close #1
#main.text "!origin 0 0" 'reset cursor

wait
[clearKey]
#main.key ""
wait
[clearText]
#main.text "!cls"
wait
[refresh]
if fileExists(DefaultDir$, "textEditor") then kill DefaultDir$;"\textEditor"
#main.text "!cls"
wait
[copytext]
#main.text "!selectall"
#main.text "!copy"
wait
[quit]
close #main
End
[advise]
notice "Key is required"
close #main
End

print "------------------------------------------------------------------------------------------------------------"

'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

sub keyPass
key2$ = key$
print key2$
end sub

sub KSA '''''key expansion ^^^^^^^^^^^
dim S(256)
dim K(256)
i = 0
j = 0
for i = 0 to 255
S(i)= i
next i
for i = 0 to 255
K(i)= asc(mid$(key2$,i mod len(key2$)+1))
next i
for i = 0 to 255
j = (j+ S(i)+ K(i))mod 256
temp = S(i)
S(i)= S(j)
S(j)= temp
next i
end sub

print "############## Encryption Functions ##################"

function txPRGA$(inString$) '''''psuedo random byte generator
i = 0
j = 0
for x = 1 to len(inString$)
i = (i + 1) mod 256 '********
byte = asc(mid$(inString$,x,1))
j = (j + S(i))mod 256
temp = S(i)
S(i) = S(j)
S(j) = temp
St = (S(i) + S(j))mod 256
k = byte xor St ''' xor text bytes with St (psuedo random bytes)
char$ = char$ + chr$(k)
next x
txPRGA$ = text2Hex$(char$)
end function

function text2Hex$(cipher$)
for i = 1 to len(cipher$) 'encrypted text
byte = asc(mid$(cipher$,i,1)) 'encrypted ascii
hex$ = decHex$(byte)
hex$ = right$("0" + hex$,2)
max$ = max$ + hex$ 'encrypted hex
next i
text2Hex$ = max$
end function

print "############# Decryption functions ###############"

function hex2Text$(hex$)
for i = 1 to len(hex$)step 2 'encrypted hex
chunk$ = mid$(hex$,i,2)
byte = hexDec(chunk$) 'encrypted ascii
text$ = text$ + chr$(byte) 'encrypted text
next i
hex2Text$= rxPRGA$(text$)
end function

function rxPRGA$(inString$) '''^^^^psuedo random byte generator
i = 0
j = 0
for x = 1 to len(inString$)
i = (i + 1) mod 256 '**********
byte = asc(mid$(inString$,x,1))
j = (j + S(i))mod 256
temp = S(i)
S(i) = S(j)
S(j) = temp
St = (S(i) + S(j))mod 256
k = byte xor St ''' xor text bytes with St (psuedo random bytes)
char$ = char$ + chr$(k)
next x
rxPRGA$ = char$
end function