例14.frm

在VB5环境下开发的VB程序集,窗体控件源代码.

VERSION 5.00
Begin VB.Form frm8_7_8 
   Caption         =   "例14:文本加、解密"
   ClientHeight    =   1725
   ClientLeft      =   60
   ClientTop       =   450
   ClientWidth     =   6165
   BeginProperty Font 
      Name            =   "宋体"
      Size            =   12
      Charset         =   134
      Weight          =   400
      Underline       =   0   'False
      Italic          =   0   'False
      Strikethrough   =   0   'False
   EndProperty
   LinkTopic       =   "Form1"
   ScaleHeight     =   1725
   ScaleWidth      =   6165
   StartUpPosition =   3  '窗口缺省
   Begin VB.CommandButton CmdRevert 
      Caption         =   "解  密"
      BeginProperty Font 
         Name            =   "宋体"
         Size            =   12
         Charset         =   134
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   615
      Left            =   3960
      TabIndex        =   2
      Top             =   480
      Width           =   1455
   End
   Begin VB.CommandButton CmdEncipher 
      Caption         =   "加  密"
      BeginProperty Font 
         Name            =   "宋体"
         Size            =   12
         Charset         =   134
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   615
      Left            =   2280
      TabIndex        =   1
      Top             =   480
      Width           =   1455
   End
   Begin VB.CommandButton CmdInText 
      Caption         =   "输入原文"
      BeginProperty Font 
         Name            =   "宋体"
         Size            =   12
         Charset         =   134
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   615
      Left            =   240
      TabIndex        =   0
      Top             =   480
      Width           =   1815
   End
End
Attribute VB_Name = "frm8_7_8"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Dim everytext As String

'声明窗体级变量，everytext保存原文
Public Function encipher(origtext As String)       '加密函数 ，形参origtext对应实参everytext
    Dim newtext As String, currchar As String, newchar As String
    Dim origlen As Integer
    origlen = Len(origtext)
    For k = 1 To origlen                           ' 逐个字符加密
    currchar = Mid$(origtext, k, 1): newchar = Chr$(Asc(currchar) + 3)
    newtext = newtext & newchar
    Next
    encipher = newtext
End Function

Public Function revert(origtext As String) As String        '  解密函数
    Dim newtext As String, currchar As String, newchar As String, origlen As Integer
    origlen = Len(origtext)
    For k = 1 To origlen                                   ' 逐个字符还原
        currchar = Mid$(origtext, k, 1): newchar = Chr$(Asc(currchar) - 3)
        newtext = newtext & newchar
    Next
    revert = newtext
End Function

Private Sub cmdintext_Click()                  ' 输入原文事件，对应图8-13中的"输入原文"按钮
    everytext = InputBox("请输入需要加密的原文", "未加密")
End Sub

Private Sub Cmdencipher_Click()                ' 加密事件，对应图8-13中的"对原文进行加密"按钮
    Dim enciphertext As String
    enciphertext = encipher(everytext)                           ' 调用加密函数过程
     MsgBox enciphertext, vbExclamation, "加密成功"     ' 对话框中显示加密的文本
End Sub

Private Sub Cmdrevert_Click()                  ' 解密事件，对应图8-13中的"对原文进行解密"按钮
   Dim reverttext As String
   reverttext = revert(encipher(everytext))
   MsgBox reverttext, vbExclamation, "解密成功"          ' 对话框中显示解密的文本
End Sub