كود vb6

Private Sub Command1_Click()
Dim encrypt
encrypt = ""
ch = Len(Text1)
For i = 1 To ch
letter = Mid(Text1, i, 1)
encrypt = encrypt & Chr(Asc(letter) + 2)
Next
Text2.Text = encrypt
End Sub

______


command 2 

Private Sub Command2_Click()
Dim encrypt
encrypt = ""
ch = Len(Text2)
For i = 1 To ch
letter = Mid(Text2, i, 1)
encrypt = encrypt & Chr(Asc(letter) - 2)
Next
Text1.Text = encrypt
End Sub