c# Sagepay XOR 加密

Question

我正在尝试在 C# 中编写异或加密，因为 sagepay 加密仅记录在 VB 中。

vb代码是：

Public Shared Function simpleXor(ByVal strIn As String, ByVal strKey As String) As String
    Dim iInIndex As Integer
    Dim iKeyIndex As Integer
    Dim strReturn As String
    If Len(strIn) = 0 Or Len(strKey) = 0 Then
        simpleXor = ""
        Exit Function
    End If

    iInIndex = 1
    iKeyIndex = 1
    strReturn = ""

    '** Step through the plain text source XORing the character at each point with the next character in the key **
    '** Loop through the key characters as necessary **
    Do While iInIndex <= Len(strIn)
        strReturn = strReturn & Chr(Asc(Mid(strIn, iInIndex, 1)) Xor Asc(Mid(strKey, iKeyIndex, 1)))
        iInIndex = iInIndex + 1
        If iKeyIndex = Len(strKey) Then iKeyIndex = 0
        iKeyIndex = iKeyIndex + 1
    Loop

    simpleXor = strReturn
End Function

到目前为止，我已将其转换为

        public static String SimpleXOR(String strIn, String strKey)
    {
        Int32 iInIndex, iKeyIndex;
        String strReturn;
        iInIndex = 1;
        iKeyIndex = 1;
        strReturn = "";

        while (iInIndex <= strIn.Length)
        {
            strReturn = strReturn & Strings.Chr(Strings.Asc(Strings.Mid(strIn, iInIndex, 1)) ^ Strings.Asc(Strings.Mid(strKey, iKeyIndex, 1)));
                iInIndex = iInIndex + 1;
            if (iKeyIndex == strKey.Length) iKeyIndex = 0;
            iKeyIndex = iKeyIndex + 1;

        }

    }

问题是我不明白这条线在做什么

strReturn = strReturn & Chr(Asc(Mid(strIn, iInIndex, 1)) Xor Asc(Mid(strKey, iKeyIndex, 1)))

所以我通过一个 vb 到 c# 转换器运行它并得到了上述结果。但据我所知，这显然不是有效的 c# 代码。

谁能帮忙？

Answer 1

我可以想到两种方法来做到这一点：

首先，获取线程的当前 System.Globalization.CultureInfo.CurrentCulture.TextInfo.ANSICodePage，使用 GetEncoding 方法将其传递给新的 Encoding 类实例，然后使用 Encoding 实例的 GetBytes 方法将字符串转换为字节数组

    public static string SimpleXOR(string strIn, string strKey)
    {
        if (strIn.Length == 0 || strKey.Length == 0)
        {
            return string.Empty;
        }

        int inIndex = 0;
        int keyIndex = 0;
        string returnString = string.Empty;

        var currentCodePage = System.Globalization.CultureInfo.CurrentCulture.TextInfo.ANSICodePage;
        var encoding = Encoding.GetEncoding(currentCodePage);

        var inString = encoding.GetBytes(strIn);
        var keyString = encoding.GetBytes(strKey);

        while (inIndex < inString.Length)
        {
            returnString += (char)(inString[inIndex] ^ keyString[keyIndex]);

            inIndex++;

            if (keyIndex == keyString.Length - 1)
            {
                keyIndex = 0;
            }
            else
            {
                keyIndex++;
            }
        }

        return returnString;
    }

另一种更简单的方法是在 C# 项目中添加对 Microsoft.VisualBasic 的引用，并让转换器生成的代码运行。 Strings 类将可用，允许您只执行 Strings.Chr、Strings.Asc 和 Strings.Mid。

Answer 2

在 C# 中，这只是

strReturn += (char)(strIn[iInIndex] ^strKey[iKeyIndex]);