Open the attached zip file and click on the button on sheet1 and follow the prompts.This article describes an easy-to-use encryption/decryption algorithm that uses XOR (XOR) operations.It can be activated within code or used in the worksheet itself (but note that keeping the key used in the worksheet rather defeats the object of the encryption code - you would probably want to copy the formula results +paste values).The functions take two arguments - the string to encrypt/decrypt and the key to use for the encyption/decryption.If bEncOrDec Then XorC = 'xxx' & XorC 'add 'xxx' onto encrypted text

If l > UBound(byKey) Then l = LBound(byKey) 'ensure stay within bounds of Key 'check whether running encryption or decryption (flagged by presence of 'xxx' at start of sData):įor i = LBound(byIn) To UBound(byIn) - 1 Step 2īyOut(i) = ((byIn(i) + Not bEncOrDec) Xor byKey(l)) - bEncOrDec 'avoid Chr$(0) by using bEncOrDec flag If Len(sData) = 0 Or Len(sKey) = 0 Then XorC = 'Invalid argument(s) used': Exit Function 'Please confirm OK or Cancel to exit', vbOKCancel, 'Confirm Key')įunction XorC(ByVal sData As String, ByVal sKey As String) As Stringĭim l As Long, i As Long, byIn() As Byte, byOut() As Byte, byKey() As Byte RetVal = MsgBox('This is the key you entered:' & vbNewLine & Chr$(34) & sKey & Chr$(34) & vbNewLine & _ SKey = Application.InputBox('Enter your key', 'Key entry', 'My Key',, ,, , 2) 'this sub is only present to demonstrate use of the function! 'it is not required to use the function. Thanks to Mdmackillop for suggested (and incorporated) improvement to the function. Longer Keys provide better encryption protection (as do longer strings to encrypt). The function adds one to the individual byte values of the generated encrypted string so that returning Ascii character 0 is avoided (Excel will not display this character and it thus causes encryption to fail). Others can still access the workbook using this method, but if they do not know the key used to encrypt the data, it is very difficult to decipher what the encrypted string is. This could be useful if you wish to send sensitive information to someone, or want to store sensitive information in a workbook, and wish to use more protection than the standard Excel interface allows (eg worksheet protection). The function makes use of bitwise Xor comparisons on the string to be encrypted and a string key provided by the user. Encrypt and decrypt strings using a Xor algorithmĮncrypts or decrypts a string of text to a string of characters based on a user-specified encryption key.

Xor Encrypt Decrypt Php