How can I use RC4 encryption for RealBasic?

[Egmont]

I have installed RealBasic on the computer of mine. I am looking to have RC4 encryption on the application of mine. however I am not aware of any code which I can used to get the requirement of mine. Let me know if you are aware of any code which I can use to apply to fix the matter of mine. I am waiting for the prompt replies of yours in this particular matter. Thanks a lot in advance.

[Amie]

Looking at the requirement of matter I am suggesting following code which you should copy and paste so that you can avoid the syntax error.

function rc4(strData as string, strKey as string) as string

   dim memAsciiArray(255) as integer
  dim memKeyArray(255)   as integer
  dim memJump            as integer
  dim memTemp            as integer
  dim memY               as integer
  dim intKeyLength       as integer
  dim intIndex           as integer
  dim intT               as integer
  dim intX               as integer
  dim strCData           as string
  
  intKeyLength = len(strKey)
  
  for intIndex = 0 to 255
    memKeyArray(intIndex)   = asc(mid(strKey, ((intIndex) mod (intKeyLength)) + 1, 1))
  next
  
  for intIndex = 0 to 255
    memAsciiArray(intIndex) = intIndex
  next
  
  for intIndex = 0 to 255
    memJump                 = (memJump + memAsciiArray(intIndex) + memKeyArray(intIndex)) mod 256
    memTemp                 = memAsciiArray(intIndex)
    memAsciiArray(intIndex) = memAsciiArray(memJump)
    memAsciiArray(memJump)  = memTemp
  next
  
  intIndex = 0
  memJump  = 0
  
  for intX = 1 to len(strData)
    intIndex                = (intIndex + 1) mod 256
    memJump                 = (memJump + memAsciiArray(intIndex)) mod 256
    intT                    = (memAsciiArray(intIndex) + memAsciiArray(memJump)) mod 256
    memTemp                 = memAsciiArray(intIndex)
    memAsciiArray(intIndex) = memAsciiArray(memJump)
    memAsciiArray(memJump)  = memTemp
    memY                    = memAsciiArray(intT)
    strCData                = strCData + chr(bitwise.bitxor(asc(mid(strData, intX, 1)), bitwise.bitxor(memTemp,memY)))
  next
  
  return strCData

end function

[HiSpeed]

I have modified the following code so that it can make use of the memory block so that there will be enhanced performance of the code. However performance will be affected by the speed of the computer.

  Dim MM as MemoryBlock = strData
  Dim MM2 as New MemoryBlock(LenB(strData))
  
  intKeyLength = len(strKey)
  
  for intIndex = 0 to 255
    memKeyArray(intIndex) = asc(mid(strKey, ((intIndex) mod (intKeyLength)) + 1, 1))
  next
  
  for intIndex = 0 to 255
    memAsciiArray(intIndex) = intIndex
  next
  
  for intIndex = 0 to 255
    memJump = (memJump + memAsciiArray(intIndex) + memKeyArray(intIndex)) mod 256
    memTemp = memAsciiArray(intIndex)
    memAsciiArray(intIndex) = memAsciiArray(memJump)
    memAsciiArray(memJump) = memTemp
  next
  
  intIndex = 0
  memJump = 0
  
  for intX = 1 to theLen
    intIndex = (intIndex + 1) mod 256
    memJump = (memJump + memAsciiArray(intIndex)) mod 256
    intT = (memAsciiArray(intIndex) + memAsciiArray(memJump)) mod 256
    memTemp = memAsciiArray(intIndex)
    memAsciiArray(intIndex) = memAsciiArray(memJump)
    memAsciiArray(memJump) = memTemp
    memY = memAsciiArray(intT)
    mm2.Byte(intX - 1) = bitwise.bitxor(val("&h" + hex(MM.byte(IntX - 1))), bitwise.bitxor(memTemp,memY))
  next
  
  return MM2

[BiGMaCHiNe]

I let you know that RC4 is seems to be symmetric function. It means that you should use the same function for both the purpose of the decryption as well as encryption. So you can use the above mentioned code for the same purpose over here.

Function rc4(strData as string, strKey as String) As String
  Dim MM as MemoryBlock = strData
  Dim MM2 as New MemoryBlock(LenB(strData))
  dim memAsciiArray(255) as integer
  dim memKeyArray(255)   as integer
  dim memJump as integer
  dim memTemp as integer
  dim memY as integer
  dim intKeyLength as integer
  dim intIndex as integer
  dim intT as integer
  dim intX as integer
  
  intKeyLength = len(strKey)
  
  for intIndex = 0 to 255
    memKeyArray(intIndex) = asc(mid(strKey, ((intIndex) mod (intKeyLength)) + 1, 1))
  next
  
  for intIndex = 0 to 255
    memAsciiArray(intIndex) = intIndex
  next
  
  for intIndex = 0 to 255
    memJump = (memJump + memAsciiArray(intIndex) + memKeyArray(intIndex)) mod 256
    memTemp = memAsciiArray(intIndex)
    memAsciiArray(intIndex) = memAsciiArray(memJump)
    memAsciiArray(memJump) = memTemp
  next
  
  intIndex = 0
  memJump = 0
  
  for intX = 1 to MM2.Size
    intIndex = (intIndex + 1) mod 256
    memJump = (memJump + memAsciiArray(intIndex)) mod 256
    intT = (memAsciiArray(intIndex) + memAsciiArray(memJump)) mod 256
    memTemp = memAsciiArray(intIndex)
    memAsciiArray(intIndex) = memAsciiArray(memJump)
    memAsciiArray(memJump) = memTemp
    memY = memAsciiArray(intT)
    mm2.Byte(intX - 1) = bitwise.bitxor(val("&h" + hex(MM.byte(IntX - 1))), bitwise.bitxor(memTemp,memY))
  next
  
  return MM2
End Function

[Connect_Me]

I am suggesting following code which you should try to get the requirement of mine and I am hoping that it will be useful to you.

  dim mm as memoryblock = s
  dim MM2 as New MemoryBlock(LenB(S))
  dim theLen as integer = LenB(S)
  dim t as integer
  
  For I as integer = 1 to theLen
    dim temp as integer = BitwiseXOR(Val("&h" + hex(mm.byte(i-1))), (128 + T * i) Mod 256)
    
    MM2.byte(i-1) = temp
  Next
  
  Return mm2

[Ronchi]

If any of the above mentioned code is not working for you than I recommend that you should use the following piece of code to meet the requirement of yours.

dim memAsciiArray(255) as integer
  dim memKeyArray(255) as Integer
  dim memJump as integer
  dim memTemp as integer
  dim memY as integer
  dim intKeyLength as integer
  dim intIndex as integer
  dim intT as integer
  dim intX as integer
  dim strCData as string
  
  Dim theLen as Integer = LenB(strData)
  Dim MM as MemoryBlock = strData
  Dim MM2 as New MemoryBlock(LenB(strData))
  
  intKeyLength = len(strKey)
  
  for intIndex = 0 to 255
    memKeyArray(intIndex) = asc(mid(strKey, ((intIndex) mod (intKeyLength)) + 1, 1))
  next
  
  for intIndex = 0 to 255
    memAsciiArray(intIndex) = intIndex
  next
  
  for intIndex = 0 to 255
    memJump = (memJump + memAsciiArray(intIndex) + memKeyArray(intIndex)) mod 256
    memTemp = memAsciiArray(intIndex)
    memAsciiArray(intIndex) = memAsciiArray(memJump)
    memAsciiArray(memJump) = memTemp
  next
  
  intIndex = 0
  memJump = 0
  
  for intX = 1 to theLen
    intIndex = (intIndex + 1) mod 256
    memJump = (memJump + memAsciiArray(intIndex)) mod 256
    intT = (memAsciiArray(intIndex) + memAsciiArray(memJump)) mod 256
    memTemp = memAsciiArray(intIndex)
    memAsciiArray(intIndex) = memAsciiArray(memJump)
    memAsciiArray(memJump) = memTemp
    memY = memAsciiArray(intT)
    mm2.Byte(intX - 1) = bitwise.bitxor(val("&h" + hex(MM.byte(IntX - 1))), bitwise.bitxor(memTemp,memY))
  next
  
  return MM2