Imports System
Imports System.Text
Imports System.Security.Cryptography

Public Class MyDES

    'DES加解密算法
    '   <summary> 
    '  加密算法 
    '   </summary>
    Public Shared Function Encrypt(ByVal pToEncrypt As String, ByVal sKey As String) As String
        Dim des As New DESCryptoServiceProvider
        Dim inputByteArray() As Byte
        inputByteArray = Encoding.Default.GetBytes(pToEncrypt)
        ''建立加密对象的密钥和偏移量
        ''原文使用ASCIIEncoding.ASCII方法的GetBytes方法
        ''使得输入密码必须输入英文文本
        des.Key = ASCIIEncoding.ASCII.GetBytes(sKey)
        des.IV = ASCIIEncoding.ASCII.GetBytes(sKey)
        ''写二进制数组到加密流
        ''(把内存流中的内容全部写入)
        Dim ms As New System.IO.MemoryStream
        Dim cs As New CryptoStream(ms, des.CreateEncryptor, CryptoStreamMode.Write)
        ''写二进制数组到加密流
        ''(把内存流中的内容全部写入)
        cs.Write(inputByteArray, 0, inputByteArray.Length)
        cs.FlushFinalBlock()
        ''建立输出字符串   
        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

    '   <summary> 
    '   解密算法 
    '   </summary>
    Public Shared Function Decrypt(ByVal pToDecrypt As String, ByVal sKey As String) As String
        Dim des As New DESCryptoServiceProvider
        ''把字符串放入byte数组
        Dim len As Integer
        len = pToDecrypt.Length / 2 - 1
        Dim inputByteArray(len) As Byte
        Dim x, i As Integer
        For x = 0 To len
            i = Convert.ToInt32(pToDecrypt.Substring(x * 2, 2), 16)
            inputByteArray(x) = CType(i, Byte)
        Next
        ''建立加密对象的密钥和偏移量，此值重要，不能修改
        des.Key = ASCIIEncoding.ASCII.GetBytes(sKey)
        des.IV = ASCIIEncoding.ASCII.GetBytes(sKey)
        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, 0, inputByteArray.Length)
    End Function

End Class