快毕业了，最后一个课程设计，《基于Windows Socket的安全通信》，内容就是基于AES加密的SOCKET通信，貌似挺简单，不过要用VC++6.0开发，C++我确实没有任何代码经验，虽然不是强制性，但由于机房里各种纠结，只能用它了（用Java没有挑战性，封装得太好了...也算熟悉下VC++吧）
先搞定AES算法，基本变换包括SubBytes（字节替代）、ShiftRows（行移位）、MixColumns（列混淆）、AddRoundKey(轮密钥加）
其算法一般描述为
明文及密钥的组织排列方式
ByteSubstitution（字节替代）
非线性的字节替代，单独处理每个字节：
求该字节在有限域GF(28)上的乘法逆，"0"被映射为自身，即对于α∈GF(28)，求β∈GF(28)，
使得α·β=β·α=1mod(x8+x4+x2+x+1)。
对上一步求得的乘法逆作仿射变换
yi=xi + x(i+4)mod8 + x(i+6)mod8 + x(i+7)mod8 + ci
(其中ci是6310即011000112的第i位），用矩阵表示为
本来打算把求乘法逆和仿射变换算法敲上去，最后还是放弃了...直接打置换表
unsigned char sBox[] = { /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ 0x63,0x7c,0x77,0x7b,0xf2,0x6b,0x6f,0xc5,0x30,0x01,0x67,0x2b,0xfe,0xd7,0xab,0x76, /*0*/ 0xca,0x82,0xc9,0x7d,0xfa,0x59,0x47,0xf0,0xad,0xd4,0xa2,0xaf,0x9c,0xa4,0x72,0xc0, /*1*/ 0xb7,0xfd,0x93,0x26,0x36,0x3f,0xf7,0xcc,0x34,0xa5,0xe5,0xf1,0x71,0xd8,0x31,0x15, /*2*/ 0x04,0xc7,0x23,0xc3,0x18,0x96,0x05,0x9a,0x07,0x12,0x80,0xe2,0xeb,0x27,0xb2,0x75, /*3*/ 0x09,0x83,0x2c,0x1a,0x1b,0x6e,0x5a,0xa0,0x52,0x3b,0xd6,0xb3,0x29,0xe3,0x2f,0x84, /*4*/ 0x53,0xd1,0x00,0xed,0x20,0xfc,0xb1,0x5b,0x6a,0xcb,0xbe,0x39,0x4a,0x4c,0x58,0xcf, /*5*/ 0xd0,0xef,0xaa,0xfb,0x43,0x4d,0x33,0x85,0x45,0xf9,0x02,0x7f,0x50,0x3c,0x9f,0xa8, /*6*/ 0x51,0xa3,0x40,0x8f,0x92,0x9d,0x38,0xf5,0xbc,0xb6,0xda,0x21,0x10,0xff,0xf3,0xd2, /*7*/ 0xcd,0x0c,0x13,0xec,0x5f,0x97,0x44,0x17,0xc4,0xa7,0x7e,0x3d,0x64,0x5d,0x19,0x73, /*8*/ 0x60,0x81,0x4f,0xdc,0x22,0x2a,0x90,0x88,0x46,0xee,0xb8,0x14,0xde,0x5e,0x0b,0xdb, /*9*/ 0xe0,0x32,0x3a,0x0a,0x49,0x06,0x24,0x5c,0xc2,0xd3,0xac,0x62,0x91,0x95,0xe4,0x79, /*a*/ 0xe7,0xc8,0x37,0x6d,0x8d,0xd5,0x4e,0xa9,0x6c,0x56,0xf4,0xea,0x65,0x7a,0xae,0x08, /*b*/ 0xba,0x78,0x25,0x2e,0x1c,0xa6,0xb4,0xc6,0xe8,0xdd,0x74,0x1f,0x4b,0xbd,0x8b,0x8a, /*c*/ 0x70,0x3e,0xb5,0x66,0x48,0x03,0xf6,0x0e,0x61,0x35,0x57,0xb9,0x86,0xc1,0x1d,0x9e, /*d*/ 0xe1,0xf8,0x98,0x11,0x69,0xd9,0x8e,0x94,0x9b,0x1e,0x87,0xe9,0xce,0x55,0x28,0xdf, /*e*/ 0x8c,0xa1,0x89,0x0d,0xbf,0xe6,0x42,0x68,0x41,0x99,0x2d,0x0f,0xb0,0x54,0xbb,0x16 /*f*/ };