Executable binary file not working after XOR encryption and decyption - encryption

Question

I want to encrypt an exe file (file.exe), write the encrypted version to a text file (fileenc.txt) and decrypt the data in the text file back to another exe file (filedec.exe).
file.exe and filedec.exe are the same and are expected to function the same way.
However, when I try to do this the filedec.exe does not work. Error Popup says: "This app cannot run on your PC".
Please what could be the problem?
However, when I just read the file.exe, write to fileenc.txt without encryption or decryption, and then read fileenc.txt and write data to filedec.exe without encryption or decryption, filedec.exe seems to work fine.
Also, when I try encrypting and decrypting a text file with this code, it works fine too.
But when I encrypt and decrypt an exe on the fly, filedec.exe doesn't work.
Please help me out. Thank you everyone.
Here is my full code:
Main();
function Main() {
var arrKey;
arrKey = "encryptionkey";
//Encrypt file.exe and write the encrypted form to file.txt
Crypt( "C:\\...\\file.exe", "C:\\...\\fileenc.txt", arrKey );
//Decrypt the previously encrypted file.txt and write the decrypted form to filedec.exe
Crypt( "C:\\...\\fileenc.txt", "C:\\...\\filedec.exe", arrKey );
//NOTE: file.exe and filedec.exe are expected to work fine when executed
}
function Crypt(fileIn, fileOut, key) {
var fileInRead;
//Read fileIn
var adTypeBinaryRead = 1;
var BinaryStreamRead;
BinaryStreamRead = new ActiveXObject("ADODB.Stream");
BinaryStreamRead.Type = adTypeBinaryRead;
BinaryStreamRead.Open();
BinaryStreamRead.LoadFromFile(fileIn);
fileInRead = BinaryStreamRead.Read();
//Convert fileIn binary data to string
var objRS = new ActiveXObject("ADODB.Recordset");
var DefinedSize = 1024;
var adSaveCreateOverWrite = 2;
var adFldLong = 0x80;
var adVarChar = 201;
var adTypeText = 2;
objRS.Fields.Append("filedata", adVarChar, DefinedSize, adFldLong);
objRS.Open();
objRS.AddNew();
objRS.Fields("filedata").AppendChunk(fileInRead);
var binString = objRS("filedata").value;
objRS.close();
//Make key as long as string version of fileIn
while (key.length < binString.length) {
key += key;
}
key = key;
//crypt converted string with key
var k, ss, q;
var cryptresult = "";
i = 0;
for (var index = 0; index < binString.length; index++) {
k = key.substr(i, 1);
q = binString.substr(i, 1);
ss = q.charCodeAt(0);
cryptresult = cryptresult + String.fromCharCode(q.charCodeAt(0) ^ k.charCodeAt(0));
i = i +1;
}
// write crypted string to file
var outStreamW = new ActiveXObject("ADODB.Stream");
outStreamW.Type = adTypeText;
// Charset: the default value seems to be `UTF-16` (BOM `0xFFFE` for text files)
outStreamW.Open();
outStreamW.WriteText(cryptresult);
outStreamW.Position = 0;
var outStreamA = new ActiveXObject("ADODB.Stream");
outStreamA.Type = adTypeText;
outStreamA.Charset = "windows-1252"; // important, see `cdoCharset Module Constants`
outStreamA.Open();
outStreamW.CopyTo(outStreamA); // convert encoding
outStreamA.SaveToFile(fileOut, adSaveCreateOverWrite);
outStreamW.Close();
outStreamA.Close();
}
EDIT:
More troubleshooting into my code shows that when I encrypt and decrypt file.exe ON THE FLY, and then write the decrypted data to fileenc.exe, fileenc.exe works well.
But when I encrypt file.exe and write the encrypted data to fileenc.txt and then read the fileenc.txt, decrypt the read encrypted data and write to fileenc.exe (just like in my code), fileenc.exe gets corrupted. My understanding suggests that the manner through which I write the encrypted data to fileenc.txt could be the problem here.
Please I need help, how do I go about with this.