Crypto: This class provides a thin wrapper around the Crypto functions that are provided with Internet Explorer, making it easy (in just 6 lines) to utilize first class encryption in your applications. InBuffer, OutBuffer, and Password are properties for setting and retrieving the string to be encoded/decoded along with the password that acts as the key for the Crypto algorithms. Methods Encrypt and Decrypt do the actual dirty work. With just two actions, it's almost a trivial class. But it provides for encryption that is far superior to simple character substitution methods. To see a sample use of Crypto and its full interface definition, scroll down.

Sub Load(UID, PtrString) As Boolean 'Loads Signature identified by UID.
Dim co       As Crypto                   'declare object
  Set co = New Crypto                    'initialize it
  co.Password = UID + ReverseString(UID) 'set encoding key
  co.InBuffer = GetSignature(UID)        'pass in string to decode
  co.Decrypt                             'decode printer string
  PtrString = co.OutBuffer               'retrieve decoded string
  Set co = Nothing                       'clean up memory
End Sub

This subroutine uses Crypto to encode a printer string that causes an HP printer to print a signature. The encryption key is just the employee Id contatenated with a reversed version of the employee Id. After setting the key all that's left to do is provide the string to be encoded, command the encryption, and retrieve the coded string.

Sub Store(UID, PtrStr) As Boolean 'Encode & Store PtrStr identified by UID. Dim co As Crypto 'declare object Set co = New Crypto 'initialize it co.Password = UID + ReverseString(UID) 'set encoding key co.InBuffer = PtrStr 'pass in string to encode co.Encrypt 'code printer string Call StoreSig(UID, co.OutBuffer) 'retrieve coded string and store Set co = Nothing 'clean up memory End Sub

The following is the full interface definition for the Crypto Class.

Public Property Get Password() As String 'Return current password Public Property Let Password(ByVal vNewValue As String) 'Set password Public Property Get InBuffer() As String 'Return input buffer Public Property Let InBuffer(ByVal vNewValue As String) 'Set input buffer Public Property Get OutBuffer() As String 'Return output buffer Public Property Let OutBuffer(ByVal vNewValue As String) 'Set output buffer Public Sub Encrypt() 'Encodes inbuffer; results in outbuffer Public Sub Decrypt() 'Decodes inbuffer; results in outbuffer