点虐 不知道怎么弄，vb倒是有文章
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asp编译成dll-图形化教程
生成的dll文件肯定要到注册到服务器上才能用。
用法嘛，和asp内置几大象的用法类似（就是面向对象），你在dll中写一个类，类中定一个加密和解密的方法，在asp里面实例化（new）这个类，用来加解密就可以了。
Private Function myEncrypt(ByVal Code As String) As String
Dim Result As String = ""
Dim CurrentChar As Char
For i As Integer = 0 To Code.Length - 1
CurrentChar = Code.Substring(i, 1)
Select Case Code.Substring(i, 1)
Case "Z"
Result = "a"
Case "z"
Result = "A"
Case Else
Result = Chr(Asc(CurrentChar) + 1)
End Select
Next
Return Result
End Function
'vb点虐 2005 调试通过
"采用DES算法"这个说法不明确，首先是使用多少位的DES进行加密，通常是128位或192位，其次是，要先把主密钥转化成散列，才能供DES进行加密，转化的方法是什么没有明确，通常是md5，所以有的银行卡说是128位md5 3DS就是指用md5转换主密钥散列，用DES进行加密，但是DES本身是64位（包含校验码），2DES是128位，3DES是192位，但是没有2DES的叫法，所以128位、192位统称3DES
要完整的md5+3DS实例，需要100分以上，要不到我的空间中查找相关的文章
使用加密方式存储即可实现别人无法查看内容，加密的方式有很多，适用你这里使用的是可逆的算法，推荐你使用DES加密
Imports System
Imports System.Collections.Generic
Imports System.Text
Imports System.IO
Imports System.Security
Imports System.Security.Cryptography
Namespace ZU14
NotInheritable Public Class DES
Private iv As String = "1234的yzo"
Private key As String = "123在yzo"
'/ summary
'/ DES加密偏移量，必须是=8位长的字符串
'/ /summary
Public Property IV() As String
Get
Return iv
End Get
Set
iv = value
End Set
End Property
'/ summary
'/ DES加密的私钥，必须是8位长的字符串
'/ /summary
Public Property Key() As String
Get
Return key
End Get
Set
key = value
End Set
End Property
'/ summary
'/ 对字符串进行DES加密
'/ /summary
'/ param name="sourceString"待加密的字符串/param
'/ returns加密后的BASE64编码的字符串/returns
Public Function Encrypt(sourceString As String) As String
Dim btKey As Byte() = Encoding.Default.GetBytes(key)
Dim btIV As Byte() = Encoding.Default.GetBytes(iv)
Dim des As New DESCryptoServiceProvider()
Dim ms As New MemoryStream()
Try
Dim inData As Byte() = Encoding.Default.GetBytes(sourceString)
Try
Dim cs As New CryptoStream(ms, des.CreateEncryptor(btKey, btIV), CryptoStreamMode.Write)
Try
cs.Write(inData, 0, inData.Length)
cs.FlushFinalBlock()
Finally
cs.Dispose()
End Try
Return Convert.ToBase64String(ms.ToArray())
Catch
End Try
Finally
ms.Dispose()
End Try
End Function 'Encrypt
'/ summary
'/ 对DES加密后的字符串进行解密
'/ /summary
'/ param name="encryptedString"待解密的字符串/param
'/ returns解密后的字符串/returns
Public Function Decrypt(encryptedString As String) As String
Dim btKey As Byte() = Encoding.Default.GetBytes(key)
Dim btIV As Byte() = Encoding.Default.GetBytes(iv)
Dim des As New DESCryptoServiceProvider()
Dim ms As New MemoryStream()
Try
Dim inData As Byte() = Convert.FromBase64String(encryptedString)
Try
Dim cs As New CryptoStream(ms, des.CreateDecryptor(btKey, btIV), CryptoStreamMode.Write)
Try
cs.Write(inData, 0, inData.Length)
cs.FlushFinalBlock()
Finally
cs.Dispose()
End Try
Return Encoding.Default.GetString(ms.ToArray())
Catch
End Try
Finally
ms.Dispose()
End Try
End Function 'Decrypt
'/ summary
'/ 对文件内容进行DES加密
'/ /summary
'/ param name="sourceFile"待加密的文件绝对路径/param
'/ param name="destFile"加密后的文件保存的绝对路径/param
Overloads Public Sub EncryptFile(sourceFile As String, destFile As String)
If Not File.Exists(sourceFile) Then
Throw New FileNotFoundException("指定的文件路径不存在！", sourceFile)
End If
Dim btKey As Byte() = Encoding.Default.GetBytes(key)
Dim btIV As Byte() = Encoding.Default.GetBytes(iv)
Dim des As New DESCryptoServiceProvider()
Dim btFile As Byte() = File.ReadAllBytes(sourceFile)
Dim fs As New FileStream(destFile, FileMode.Create, FileAccess.Write)
Try
Try
Dim cs As New CryptoStream(fs, des.CreateEncryptor(btKey, btIV), CryptoStreamMode.Write)
Try
cs.Write(btFile, 0, btFile.Length)
cs.FlushFinalBlock()
Finally
cs.Dispose()
End Try
Catch
Finally
fs.Close()
End Try
Finally
fs.Dispose()
End Try
End Sub 'EncryptFile
'/ summary
'/ 对文件内容进行DES加密，加密后覆盖掉原来的文件
'/ /summary
'/ param name="sourceFile"待加密的文件的绝对路径/param
Overloads Public Sub EncryptFile(sourceFile As String)
EncryptFile(sourceFile, sourceFile)
End Sub 'EncryptFile
'/ summary
'/ 对文件内容进行DES解密
'/ /summary
'/ param name="sourceFile"待解密的文件绝对路径/param
'/ param name="destFile"解密后的文件保存的绝对路径/param
Overloads Public Sub DecryptFile(sourceFile As String, destFile As String)
If Not File.Exists(sourceFile) Then
Throw New FileNotFoundException("指定的文件路径不存在！", sourceFile)
End If
Dim btKey As Byte() = Encoding.Default.GetBytes(key)
Dim btIV As Byte() = Encoding.Default.GetBytes(iv)
Dim des As New DESCryptoServiceProvider()
Dim btFile As Byte() = File.ReadAllBytes(sourceFile)
Dim fs As New FileStream(destFile, FileMode.Create, FileAccess.Write)
Try
Try
Dim cs As New CryptoStream(fs, des.CreateDecryptor(btKey, btIV), CryptoStreamMode.Write)
Try
cs.Write(btFile, 0, btFile.Length)
cs.FlushFinalBlock()
Finally
cs.Dispose()
End Try
Catch
Finally
fs.Close()
End Try
Finally
fs.Dispose()
End Try
End Sub 'DecryptFile
'/ summary
'/ 对文件内容进行DES解密，加密后覆盖掉原来的文件
'/ /summary
'/ param name="sourceFile"待解密的文件的绝对路径/param
Overloads Public Sub DecryptFile(sourceFile As String)
DecryptFile(sourceFile, sourceFile)
End Sub 'DecryptFile
End Class 'DES
End Namespace 'ZU14
对文本文件加密
Dim des As New ZU14.DES()
des.IV = "abcd哈哈笑"
des.Key = "必须八位"
'加密
des.EncryptFile("d:\a.txt", "d:\b.txt")
'解密
des.DecryptFile("d:\b.txt")