VB 加密解密程序

' 加密解密程序
'
'
'---------------------------------------------------------------------------------------------------------------
Function cipher(stext As String) '密码加密程序
Const min_asc = 32
Const max_asc = 126
Const num_asc = max_asc - min_asc + 1
Dim offset As Long
Dim strlen As Integer
Dim i As Integer
Dim ch As Integer
Dim ptext As String
offset = 123
Rnd (-1)
Randomize (offset)
strlen = Len(stext)
For i = 1 To strlen
ch = Asc(Mid(stext, i, 1))
If ch >= min_asc And ch <= max_asc Then
ch = ch - min_asc
offset = Int((num_asc + 1) * Rnd())
ch = ((ch + offset) Mod num_asc)
ch = ch + min_asc
ptext = ptext & Chr(ch)
End If
Next i
cipher = ptext
End Function

Function decipher(stext As String) '密码解密程序
Const min_asc = 32 '最小ASCII码
Const max_asc = 126 '最大ASCII码 字符
Const num_asc = max_asc - min_asc + 1
Dim offset As Long
Dim strlen As Integer
Dim i As Integer
Dim ch As Integer
Dim ptext As String
offset = 123
Rnd (-1)
Randomize (offset)
strlen = Len(stext)
For i = 1 To strlen
ch = Asc(Mid(stext, i, 1)) '取字母转变成ASCII码
If ch >= min_asc And ch <= max_asc Then
ch = ch - min_asc
offset = Int((num_asc + 1) * Rnd())
ch = ((ch - offset) Mod num_asc)
If ch < 0 Then
ch = ch + num_asc
End If
ch = ch + min_asc
ptext = ptext & Chr(ch)
End If
Next i
decipher = ptext
End Function