ARCHIVE: TIPS & TRICKS
A simple encryption function
John Walker
10.10.2000
Rating: -3.62- (out of 5)
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
String
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 www.PGP.com.
John, thanks for the great tip for our readers, and to show our
appreciation, we're sending you a free searchVB.com 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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