用VB.NET編寫DES加密－冠霖的部落格

在VB.NET中編寫DEC加密程序是很容易的事情，因為VB.NET的類庫中就自帶了相應的函數，下面分別是加密函數和解密函數。

加密函數：

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)
        ''建立加密對象的密鑰和偏移量
        ''原文使用ASCIIEncoding.ASCII方法的GetBytes方法
        ''使得輸入密碼必須輸入英文文本
        des.Key = ASCIIEncoding.ASCII.GetBytes(sKey)
        des.IV = ASCIIEncoding.ASCII.GetBytes(sKey)
        ''寫二進制數組到加密流
        ''(把內存流中的內容全部寫入)
        Dim ms As New System.IO.MemoryStream()
        Dim cs As New CryptoStream(ms, des.CreateEncryptor, CryptoStreamMode.Write)
        ''寫二進制數組到加密流
        ''(把內存流中的內容全部寫入)
        cs.Write(inputByteArray, 0, inputByteArray.Length)
        cs.FlushFinalBlock()

        ''建立輸出字符串
        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

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解密函數：

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數組
        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
        ''建立加密對象的密鑰和偏移量，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)

End Function

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兩個函數中第一個參數是待加密或解密的字符串，sKey是使用的密鑰，必須是8位，使用的時候要注意哦，不然會出錯的。