Xor algorithm with no special characters using VBA - vba

Question

For a project I am developing I need to use some kind of encryption algorithm to encrypt some sensitive data, where each user has a unique hex key.
Basically I have to encrypt a string and write it to a file to import to a Access database (we are not authorised to use other RDBMS as the company policies don't allow it).
So while researching what algorithms to use, I've came across this awesome sample of an XOR algorithm from VBA Express, but there are some limitations with this particular algorithm (please correct me if I'm wrong) :
For certain combinations of string vs key, a overflow happens;
Excel uses a "different" ASCII code table which causes some entropy as well (can't use the first 32 codes because they refer to special characters);
I want to avoid special characters (line feeds, carriage returns) because I want to write to a file and if they exist I can't read the file as the splits will go bad.
With this being said, I can't maintain a 1 to 1 relationship of encoding and decoding.
So should I use another encryption system or are there changes should I do to fix this bad encryption?
Should I use another reading/writing file system other than line by line?
The code to generate the keys to test
Private Sub getDictionaryValues()
Dim atc As String
Dim wsheet As Worksheet
Dim wstmp As Worksheet
Dim rng As Range
Dim k As Long, j As Long
Dim arrrr(1 To 223) As String
Dim arc()
On Error Resume Next
j = 2
Set wsheet = ThisWorkbook.Worksheets("Sheet4")
arc = Array("0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "A", "B", "C", "D", "E", "F")
For i = 33 To 255
arrrr(i - 32) = Chr(i)
Next i
For k = LBound(arc) To UBound(arc)
For i = LBound(arrrr) To UBound(arrrr)
atc = XorC(arrrr(i), arc(k))
wsheet.Range(Cells(j, 1), Cells(j, 1)) = arc(k)
wsheet.Range(Cells(j, 2), Cells(j, 2)) = i + 32
wsheet.Range(Cells(j, 3), Cells(j, 3)) = arrrr(i)
wsheet.Range(Cells(j, 4), Cells(j, 4)) = Right(atc, Len(atc) - 3)
wsheet.Cells(j, 5) = XorC(atc, arc(k))
'wsheet.Cells(j, 6) = getUnicode(arrrr(i), arc(k))
j = j + 1
Next i
atc = vbNullString
Next k
End Sub
My version of the Xor algorithm
Function XorC(ByVal sData As String, ByVal sKey As String) As String
Dim l As Long, i As Long, byIn() As Byte, byOut() As Byte, byKey() As Byte
Dim bEncOrDec As Boolean
Dim addVal
If Len(sData) = 0 Or Len(sKey) = 0 Then XorC = "Invalid argument(s) used": Exit Function
If Left$(sData, 3) = "xxx" Then
bEncOrDec = False 'decryption
sData = Mid$(sData, 4)
Else
bEncOrDec = True 'encryption
End If
byIn = sData
byOut = sData
byKey = sKey
If bEncOrDec = True Then
addVal = 32
Else
addVal = 1 * -32
End If
l = LBound(byKey)
For i = LBound(byIn) To UBound(byIn) - 1 Step 2
If (((byIn(i) + Not bEncOrDec) Xor byKey(l)) + addVal) > 255 Then
byOut(i) = (((byIn(i) + Not bEncOrDec) Xor byKey(l)) + addVal) Mod 255 + addVal
Else
'If bEncOrDec Then
If ((byIn(i) + Not bEncOrDec) Xor byKey(l)) - addVal < 32 Then byOut(i) = ((byIn(i) + Not bEncOrDec) Xor byKey(l)) + addVal
If ((byIn(i) + Not bEncOrDec) Xor byKey(l)) - addVal > 255 Then byOut(i) = ((byIn(i) + Not bEncOrDec) Xor byKey(l)) - addVal
If ((byIn(i) + Not bEncOrDec) Xor byKey(l)) > 32 And (byIn(i) + Not bEncOrDec) Xor byKey(l) < 256 Then byOut(i) = ((byIn(i) + Not bEncOrDec) Xor byKey(l))
End If
l = l + 2
If l > UBound(byKey) Then l = LBound(byKey)
Next i
XorC = byOut
If bEncOrDec Then XorC = "xxx" & XorC 'add "xxx" onto encrypted text
End Function