VB.NET的MD5算法(转)

'DES及md5加密解密----添加引用中添加对system.web的引用。
Imports System.Security.Cryptography
Imports System
Imports System.Text
Imports System.Web
''' <summary>
''' DES加密类
''' </summary>
''' <remarks></remarks>
Public Class DESEncrypt
    Public Sub DESEncrypt()
    End Sub
    Public Shared Function Encrypt(ByVal Text As String) As String
        Return Encrypt(Text, "12345678")
    End Function
    Public Shared Function Encrypt(ByVal Text As String, ByVal sKey As String) As String
        Dim des As New DESCryptoServiceProvider()
        Dim inputByteArray As Byte()
        inputByteArray = Encoding.Default.GetBytes(Text)
        des.Key = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(0, 8))
        des.IV = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(0, 8))
        Dim ms As New System.IO.MemoryStream()
        Dim cs As New CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write)
        cs.Write(inputByteArray, 0, inputByteArray.Length)
        cs.FlushFinalBlock()
        Dim ret As New StringBuilder()
        Dim b As Byte
        For Each b In ms.ToArray()
            ret.AppendFormat("{0:X2}", b)
        Next
        Return ret.ToString()
    End Function
    Public Shared Function Decrypt(ByVal Text As String) As String
        Return Decrypt(Text, "12345678")
    End Function
    Public Shared Function Decrypt(ByVal Text As String, ByVal sKey As String) As String
        Dim des As New DESCryptoServiceProvider()
        Dim len As Integer
        len = Text.Length / 2
        Dim inputByteArray(len - 1) As Byte
        Dim x, i As Integer
        For x = 0 To len - 1
            i = Convert.ToInt32(Text.Substring(x * 2, 2), 16)
            inputByteArray(x) = CType(i, Byte)
        Next
        des.Key = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(0, 8))
        des.IV = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(0, 8))
        Dim ms As New System.IO.MemoryStream()
        Dim cs As New CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write)
        cs.Write(inputByteArray, 0, inputByteArray.Length)
        cs.FlushFinalBlock()
        Return Encoding.Default.GetString(ms.ToArray())
    End Function
End Class
'以下是调用方法
Public Class Form1
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click '加密
        Dim str_Encrypt As String = DESEncrypt.Encrypt("你要加密的文本，可以是任意长度", "密码，可以很长，如果省略这个参数就是默认的12345678")
    End Sub
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click '解密
        Dim str_Decrypt As String = DESEncrypt.Decrypt("你要解密的文本, 可以是任意长度", "加密时用到的密码，如果省略这个参数就是默认的12345678")
    End Sub