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我正在尝试使用计算 MAC

加密校验和使用 ISOIEC 9797-1 MAC 算法 3 计算，采用分组密码 DES、零 IV（8 字节）和 1S09797-1 填充方法 2。MAC 长度必须为 8 字节

来自提供 ICC 只读访问权限的机读旅行证件技术报告 PM 发布：1.1 日期：2004 年 10 月 1 日。

我正在使用报告中的示例值：

肯克：AB 94 FD EC F2 67 4F DF B9 B3 91 F8 5D 7F 76 F2

Kmac: 79 62 D9 EC E0 3D 1A CD 4C 76 08 9D CE 13 15 43

eIFD: 72 C2 9C 23 71 CC 9B DB 65 B7 79 B8 E8 D3 7B 29 EC C1 54 AA 56 A8 79 9F AE 2F 49 8F 76 ED 92 F2

但是，我没有得到相同的 MAC，并且不确定我需要如何去做。我的第一次尝试是：

                MACTripleDES mac = new System.Security.Cryptography.MACTripleDES(Kmac);
                mac.Initialize();
                mac.Padding = PaddingMode.None;
                mac.Key = Kmac;
                mIfd = mac.TransformFinalBlock(eIfd, 0, eIfd.Length);

结果：

mIFD:1C DE 09 70 4C 0D 9B 12

预期的：

mIFD:5F 14 48 EE A8 AD 90 A7

然后我尝试手动执行每个步骤，因为我理解“ISO/IEC 9797-1 MAC 算法 3，带有分组密码 DES、零 IV（8 字节）和 1S09797-1 填充方法 2”，具体如下：（我基于Rasmus Faber 的回答，但将数据拆分为 64 位块以进行迭代步骤）

                byte[] key1 = new byte[8];
                Array.Copy(kMAC, 0, key1, 0, 8);
                byte[] key2 = new byte[8];
                Array.Copy(kMAC, 8, key2, 0, 8);
                Console.WriteLine("key1:{0}", Hex.BytesToSpacedHexString(key1));
                Console.WriteLine("key2:{0}", Hex.BytesToSpacedHexString(key2));

                // Plit the blocks
                byte[] d1 = new byte[8];
                byte[] d2 = new byte[8];
                byte[] d3 = new byte[8];
                byte[] d4 = new byte[8];
                Array.Copy(eIfd, 0, d1, 0, 8);
                Array.Copy(eIfd, 8, d2, 0, 8);
                Array.Copy(eIfd, 16, d3, 0, 8);
                Array.Copy(eIfd, 24, d4, 0, 8);

                DES des1 = DES.Create();
                des1.BlockSize = 64;
                des1.Key = key1;
                des1.Mode = CipherMode.CBC;
                des1.Padding = PaddingMode.None;
                des1.IV = new byte[8];

                DES des2 = DES.Create();
                des2.BlockSize = 64;
                des2.Key = key2;
                des2.Mode = CipherMode.CBC;
                des2.Padding = PaddingMode.None;
                des2.IV = new byte[8];

                // MAC Algorithm 3
                // Initial Transformation 1
                byte[] h1 = des1.CreateEncryptor().TransformFinalBlock(d1, 0, 8);
                // Iteration on the rest of blocks
                // XOR
                byte[] int2 = new byte[8];
                for (int i = 0; i < 8; i++)
                    int2[i] = (byte)(h1[i] ^ d2[i]);
                // Encrypt
                byte[] h2 = des1.CreateEncryptor().TransformFinalBlock(int2, 0, 8);
                // XOR
                byte[] int3 = new byte[8];
                for (int i = 0; i < 8; i++)
                    int3[i] = (byte)(h2[i] ^ d3[i]);
                // Encrypt
                byte[] h3 = des1.CreateEncryptor().TransformFinalBlock(int3, 0, 8);
                // XOR
                byte[] int4 = new byte[8];
                for (int i = 0; i < 8; i++)
                    int4[i] = (byte)(h3[i] ^ d4[i]);
                // Encrypt
                byte[] h4 = des1.CreateEncryptor().TransformFinalBlock(int4, 0, 8);

                // Output Transformation 3
                byte[] h4decrypt = des2.CreateDecryptor().TransformFinalBlock(h4, 0, 8);
                mIfd = des1.CreateEncryptor().TransformFinalBlock(h4decrypt, 0, 8);
                Console.WriteLine("mIFD:{0}", Hex.BytesToSpacedHexString(mIfd));

输出是：

eIFD:72 C2 9C 23 71 CC 9B DB 65 B7 79 B8 E8 D3 7B 29 EC C1 54 AA 56 A8 79 9F AE 2F 49 8F 76 ED 92 F2

key1:79 62 D9 EC E0 3D 1A CD

key2:4C 76 08 9D CE 13 15 43

结果：

mIFD:AA E3 F3 51 32 ED 34 65

预期的：

mIFD:5F 14 48 EE A8 AD 90 A7

在这两种情况下，它与预期的不同。我错过了什么？

感谢您的时间。

4

3 回答 3

5

感谢 owlstead，诀窍是即使数据字符串正好是 32 个字节，也必须进行填充。对于需要完整代码的人。MAC哈希的代码

eIFD:72 C2 9C 23 71 CC 9B DB 65 B7 79 B8 E8 D3 7B 29 EC C1 54 AA 56 A8 79 9F AE 2F 49 8F 76 ED 92 F2

数据字符串如下所示：

                // Split the 16 byte MAC key into two keys
            byte[] key1 = new byte[8];
            Array.Copy(kMAC, 0, key1, 0, 8);
            byte[] key2 = new byte[8];
            Array.Copy(kMAC, 8, key2, 0, 8);
            Console.WriteLine("key1:{0}", Hex.BytesToSpacedHexString(key1));
            Console.WriteLine("key2:{0}", Hex.BytesToSpacedHexString(key2));

            // Padd the data with Padding Method 2 (Bit Padding)
            System.IO.MemoryStream out_Renamed = new System.IO.MemoryStream();
            out_Renamed.Write(eIfd, 0, eIfd.Length);
            out_Renamed.WriteByte((byte)(0x80));
            while (out_Renamed.Length % 8 != 0)
            {
                out_Renamed.WriteByte((byte)0x00);
            }
            byte[] eIfd_padded = out_Renamed.ToArray();
            Console.WriteLine("eIfd_padded:{0}", Hex.BytesToSpacedHexString(eIfd_padded));

            // Split the blocks
            byte[] d1 = new byte[8];
            byte[] d2 = new byte[8];
            byte[] d3 = new byte[8];
            byte[] d4 = new byte[8];
            byte[] d5 = new byte[8];
            Array.Copy(eIfd_padded, 0, d1, 0, 8);
            Array.Copy(eIfd_padded, 8, d2, 0, 8);
            Array.Copy(eIfd_padded, 16, d3, 0, 8);
            Array.Copy(eIfd_padded, 24, d4, 0, 8);
            Array.Copy(eIfd_padded, 32, d5, 0, 8);

            DES des1 = DES.Create();
            des1.BlockSize = 64;
            des1.Key = key1;
            des1.Mode = CipherMode.CBC;
            des1.Padding = PaddingMode.None;
            des1.IV = new byte[8];

            DES des2 = DES.Create();
            des2.BlockSize = 64;
            des2.Key = key2;
            des2.Mode = CipherMode.CBC;
            des2.Padding = PaddingMode.None;
            des2.IV = new byte[8];

            // MAC Algorithm 3
            // Initial Transformation 1
            byte[] h1 = des1.CreateEncryptor().TransformFinalBlock(d1, 0, 8);
            // Iteration on the rest of blocks
            // XOR
            byte[] int2 = new byte[8];
            for (int i = 0; i < 8; i++)
                int2[i] = (byte)(h1[i] ^ d2[i]);
            // Encrypt
            byte[] h2 = des1.CreateEncryptor().TransformFinalBlock(int2, 0, 8);
            // XOR
            byte[] int3 = new byte[8];
            for (int i = 0; i < 8; i++)
                int3[i] = (byte)(h2[i] ^ d3[i]);
            // Encrypt
            byte[] h3 = des1.CreateEncryptor().TransformFinalBlock(int3, 0, 8);
            // XOR
            byte[] int4 = new byte[8];
            for (int i = 0; i < 8; i++)
                int4[i] = (byte)(h3[i] ^ d4[i]);
            // Encrypt
            byte[] h4 = des1.CreateEncryptor().TransformFinalBlock(int4, 0, 8);
            // XOR
            byte[] int5 = new byte[8];
            for (int i = 0; i < 8; i++)
                int5[i] = (byte)(h4[i] ^ d5[i]);
            // Encrypt
            byte[] h5 = des1.CreateEncryptor().TransformFinalBlock(int5, 0, 8);

            // Output Transformation 3
            byte[] h5decrypt = des2.CreateDecryptor().TransformFinalBlock(h5, 0, 8);
            byte[] mIfd = des1.CreateEncryptor().TransformFinalBlock(h5decrypt, 0, 8);
            Console.WriteLine("mIFD:{0}", Hex.BytesToSpacedHexString(mIfd));
于 2013-12-02T16:31:23.947 回答
4

您至少缺少填充模式。ICAO 技术规范使用位填充（至少一个字节值80，然后是一到七个00值字节，直到到达块的末尾。

于 2013-12-01T18:30:36.323 回答
3

感谢分享代码。这是一个很好的例子。我已更改代码以解决任何大小的块，而不仅仅是 5 个字节。现在在下面的代码中，可以使用从块的单个字节到块中任何大小的字节来获取 MAC。

    private static byte[] getCC_MACNbytes(string Key_MAC, byte[] eIFD, string Init_Vec)
    {
        byte[] Kmac = StringToByteArray(Key_MAC);

        // Split the 16 byte MAC key into two keys
        byte[] key1 = new byte[8];
        Array.Copy(Kmac, 0, key1, 0, 8);
        byte[] key2 = new byte[8];
        Array.Copy(Kmac, 8, key2, 0, 8);

        DES des1 = DES.Create();
        des1.BlockSize = 64;
        des1.Key = key1;
        des1.Mode = CipherMode.CBC;
        des1.Padding = PaddingMode.None;
        des1.IV = new byte[8];

        DES des2 = DES.Create();
        des2.BlockSize = 64;
        des2.Key = key2;
        des2.Mode = CipherMode.CBC;
        des2.Padding = PaddingMode.None;
        des2.IV = new byte[8];

        // Padd the data with Padding Method 2 (Bit Padding)
        System.IO.MemoryStream out_Renamed = new System.IO.MemoryStream();
        out_Renamed.Write(eIFD, 0, eIFD.Length);
        out_Renamed.WriteByte((byte)(0x80));
        while (out_Renamed.Length % 8 != 0)
        {
            out_Renamed.WriteByte((byte)0x00);
        }
        byte[] eIfd_padded = out_Renamed.ToArray();
        int N_bytes = eIfd_padded.Length/8;  // Number of Bytes 

        byte[] d1 = new byte[8];
        byte[] dN = new byte[8];
        byte[] hN = new byte[8];
        byte[] intN = new byte[8];

        // MAC Algorithm 3
        // Initial Transformation 1
        Array.Copy(eIfd_padded, 0, d1, 0, 8);
        hN = des1.CreateEncryptor().TransformFinalBlock(d1, 0, 8);

        // Split the blocks
        // Iteration on the rest of blocks
        for (int j = 1; j<N_bytes; j++)
        {
            Array.Copy(eIfd_padded, (8*j), dN, 0, 8);
            // XOR
            for (int i = 0; i < 8; i++)
                intN[i] = (byte)(hN[i] ^ dN[i]);

            // Encrypt
            hN = des1.CreateEncryptor().TransformFinalBlock(intN, 0, 8);
        }

        // Output Transformation 3
        byte[] hNdecrypt = des2.CreateDecryptor().TransformFinalBlock(hN, 0, 8);
        byte[] mIfd = des1.CreateEncryptor().TransformFinalBlock(hNdecrypt, 0, 8);

        //  Get check Sum CC
        return mIfd;
    }
于 2014-11-29T12:59:44.780 回答