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A simple encryption function

This tip provides a simple Visual Basic encryption function.

A Simple Encryption Function

There will be times that you just need a little something to make text more secure, but you don't want to go to the bother and expense of buying one of the pre-packaged solutions commercially available.

Reader John Walker sends this simple little function that will encrypt text that you don't want snoopers to see easily.

Sometimes you might want to make life more difficult for snoopy people. This little encryption function won't scare the NSA; but, like a cheap lock, It'll keep honest people honest. To encrypt, feed it the plain text (text to be encrypted) of any length (within system limits) and a Key of any length. The function returns the encrypted string. To decrypt just use the Crypt function to run the encrypted text through the same key.

Private Function Crypt(ByVal Text As String, ByVal Key As String) As
Dim i As Long, KeyLen As Long, KeyPtr As Long, KeyChr As Integer,
TextChr As Integer
KeyLen = Len(Key)
For i = 1 To Len(Text)
TextChr = Asc(Mid(Text, i, 1))
KeyChr = Asc(Mid(Key, KeyPtr + 1, 1))
Mid(Text, i, 1) = Chr(TextChr Xor KeyChr)
KeyPtr = ((KeyPtr + 1) Mod KeyLen)
Next i
Crypt = Text
End Function

TIP II - If you have personal needs for more robust encryption you can download a free desktop version of the PGP (Pretty Good Privacy) software from

John, thanks for the great tip for our readers, and to show our appreciation, we're sending you a free denim shirt. Enjoy!

John Walker is an Information Systems Consultant for Metro Information Services located in Wheat Ridge, Colo. He specializes in Visual Basic, APL, SQL server and other applications.

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