将字母A变成字母E,a变成e,即变成其后的第4个字母,W变成A,X变成B,Y变成C,Z变成D

Private Sub Form_Click()
Dim i As Integer,c As Integer,k As Integer
k = 4
Label1.Caption = ""
For i = 1 To Len(Text1.Text)
c = Asc(Mid(Text1.Text,i,1)) + k
If c > Asc("z") Or c > Asc("Z") And c < Asc("a") + k Then c = c - 26
Label1.Caption = Label1.Caption & Chr(c)
Next
End Sub

以上代码用Text1放需要加密的字符串,Label1放加密后的字符串.点击窗体执行.