我正在尝试使用
计算MAC使用ISOIEC 9797-1 MAC计算加密校验和 算法3使用分组密码DES，零IV（8字节）和1S09797-1 填充方法2. MAC长度必须是8字节
提供机读旅行证件的技术报告PM提供ICC只读访问版本：1。1日期：2004年10月1日。
我正在使用报告中的示例值：
Kenc：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
然而，我没有得到相同的MAC，也不确定我需要怎么做。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：
mIFD：5F 14 48 EE A8 AD 90 A7
然后我尝试手动完成每一步，因为我理解“ISO / IEC 9797-1 MAC算法3使用分组密码DES，零IV（8字节）和1S09797-1填充方法2”，具有以下内容：（I基于此Rasmus Faber's answer，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));
输出结果为：
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：
mIFD：5F 14 48 EE A8 AD 90 A7
在这两种情况下，它都与预期的不同。我错过了什么？
感谢您的时间。
答案 0 :(得分：5)
感谢owlstead，诀窍是即使数据字符串正好是32字节，也必须填充。对于需要完整代码的人。
的MAC哈希代码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));
答案 1 :(得分：4)
您至少缺少填充模式。 ICAO技术规范使用位填充（至少一个值为80的字节，然后是一到七00个值的字节，直到到达块的末尾。
答案 2 :(得分：2)
感谢您分享代码。这是一个很好的例子。我已经改变了代码来解决任何大小的块而不是5个字节。现在在下面的代码中，可以使用块的单个字节到块中的任何字节大小来获取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;
}