数组异或有关问题

数组异或问题
Dim   FileData()   as   byte
Dim   FileName   as   String
Filename= "C:\1.ogg "
Redim   FileData(FileLen(Filename))
Open   FileName   for   binary   as   #1
Get   #1,1,Filedata
Close   #1

然后需要把Filedata当中每4个节和字符串abcd异或，如果文件大小不为4的倍数，则最后剩余的不足4字节的部分不进行加密...
T_T   怎么写代码？

[解决办法]
上面发错了
Dim FileData() as byte
Dim FileName as String
Filename= "C:\1.ogg "
Redim FileData(Filelen(filename)-1) as byte
Open FileName for binary as #1
Get #1,1,Filedata
Close #1
dim i as integer
dim lenmax as integer
lenmax = Filelen(filename)
if lenmax mod 4 <> 0 then
lenmax = lenmax - (lenmax mod 4)
end if

for i = 0 to lenmax step 4
Filedata(i) = Filedata(i) and 65
Filedata(i+1) = Filedata(i+1) and 66
Filedata(i+2) = Filedata(i+2) and 67
Filedata(i+3) = Filedata(i+3) and 68
next