360 lines
12 KiB
C
360 lines
12 KiB
C
/*
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* 标准AES-128-CBC实现 - 与OpenSSL完全兼容
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* 基于FIPS-197标准
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*/
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#include "aes.h"
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#include <string.h>
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// S-box
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static const uint8_t sbox[256] = {
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0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76,
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0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0,
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0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,
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0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75,
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0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84,
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0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,
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0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8,
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0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2,
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0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,
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0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb,
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0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79,
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0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,
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0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a,
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0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e,
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0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,
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0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16
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};
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static const uint8_t rsbox[256] = {
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0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb,
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0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb,
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0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e,
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0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25,
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0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92,
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0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84,
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0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06,
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0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b,
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0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73,
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0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e,
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0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b,
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0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4,
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0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f,
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0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef,
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0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61,
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0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d
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};
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// Rcon
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static const uint8_t Rcon[11] = {
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0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36
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};
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#define getSBoxValue(num) (sbox[(num)])
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#define getSBoxInvert(num) (rsbox[(num)])
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// 密钥扩展
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/* 函数作用：根据 AES-128 主密钥生成每轮加密使用的轮密钥。 */
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static void KeyExpansion(uint8_t* RoundKey, const uint8_t* Key)
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{
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unsigned i, j, k;
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uint8_t tempa[4];
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// 前4个轮密钥直接复制
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for (i = 0; i < 4; ++i) {
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RoundKey[(i * 4) + 0] = Key[(i * 4) + 0];
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RoundKey[(i * 4) + 1] = Key[(i * 4) + 1];
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RoundKey[(i * 4) + 2] = Key[(i * 4) + 2];
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RoundKey[(i * 4) + 3] = Key[(i * 4) + 3];
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}
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// 生成其余轮密钥
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for (i = 4; i < 44; ++i) {
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k = (i - 1) * 4;
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tempa[0] = RoundKey[k + 0];
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tempa[1] = RoundKey[k + 1];
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tempa[2] = RoundKey[k + 2];
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tempa[3] = RoundKey[k + 3];
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if (i % 4 == 0) {
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// RotWord
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const uint8_t u8tmp = tempa[0];
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tempa[0] = tempa[1];
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tempa[1] = tempa[2];
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tempa[2] = tempa[3];
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tempa[3] = u8tmp;
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// SubWord
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tempa[0] = getSBoxValue(tempa[0]);
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tempa[1] = getSBoxValue(tempa[1]);
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tempa[2] = getSBoxValue(tempa[2]);
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tempa[3] = getSBoxValue(tempa[3]);
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tempa[0] = tempa[0] ^ Rcon[i / 4];
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}
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j = i * 4;
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k = (i - 4) * 4;
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RoundKey[j + 0] = RoundKey[k + 0] ^ tempa[0];
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RoundKey[j + 1] = RoundKey[k + 1] ^ tempa[1];
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RoundKey[j + 2] = RoundKey[k + 2] ^ tempa[2];
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RoundKey[j + 3] = RoundKey[k + 3] ^ tempa[3];
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}
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}
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// AddRoundKey
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/* 函数作用：将当前状态矩阵与指定轮密钥进行异或。 */
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static void AddRoundKey(uint8_t round, uint8_t* state, const uint8_t* RoundKey)
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{
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uint8_t i, j;
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for (i = 0; i < 4; ++i) {
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for (j = 0; j < 4; ++j) {
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state[i * 4 + j] ^= RoundKey[(round * 16) + (i * 4 + j)];
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}
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}
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}
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// SubBytes
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/* 函数作用：使用 AES S 盒对状态矩阵进行字节替换。 */
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static void SubBytes(uint8_t* state)
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{
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uint8_t i;
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for (i = 0; i < 16; ++i) {
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state[i] = getSBoxValue(state[i]);
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}
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}
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// ShiftRows
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/* 函数作用：执行 AES 加密流程中的行移位变换。 */
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static void ShiftRows(uint8_t* state)
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{
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uint8_t temp;
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// 第二行左移1字节
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temp = state[1];
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state[1] = state[5];
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state[5] = state[9];
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state[9] = state[13];
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state[13] = temp;
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// 第三行左移2字节
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temp = state[2];
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state[2] = state[10];
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state[10] = temp;
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temp = state[6];
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state[6] = state[14];
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state[14] = temp;
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// 第四行左移3字节
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temp = state[15];
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state[15] = state[11];
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state[11] = state[7];
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state[7] = state[3];
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state[3] = temp;
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}
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// xtime (用于MixColumns)
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/* 函数作用：在 AES 有限域中执行乘以 2 的运算。 */
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static uint8_t xtime(uint8_t x)
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{
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return ((x << 1) ^ (((x >> 7) & 1) * 0x1b));
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}
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// MixColumns
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/* 函数作用：执行 AES 加密流程中的列混淆变换。 */
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static void MixColumns(uint8_t* state)
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{
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uint8_t i;
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uint8_t Tmp, Tm, t;
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for (i = 0; i < 4; ++i) {
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t = state[i * 4 + 0];
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Tmp = state[i * 4 + 0] ^ state[i * 4 + 1] ^ state[i * 4 + 2] ^ state[i * 4 + 3];
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Tm = state[i * 4 + 0] ^ state[i * 4 + 1];
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Tm = xtime(Tm);
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state[i * 4 + 0] ^= Tm ^ Tmp;
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Tm = state[i * 4 + 1] ^ state[i * 4 + 2];
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Tm = xtime(Tm);
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state[i * 4 + 1] ^= Tm ^ Tmp;
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Tm = state[i * 4 + 2] ^ state[i * 4 + 3];
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Tm = xtime(Tm);
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state[i * 4 + 2] ^= Tm ^ Tmp;
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Tm = state[i * 4 + 3] ^ t;
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Tm = xtime(Tm);
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state[i * 4 + 3] ^= Tm ^ Tmp;
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}
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}
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// Cipher - AES加密核心
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/* 函数作用：对 16 字节状态块执行完整 AES 加密。 */
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static void Cipher(uint8_t* state, const uint8_t* RoundKey)
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{
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uint8_t round = 0;
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// 初始轮密钥加
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AddRoundKey(0, state, RoundKey);
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// 9轮标准变换
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for (round = 1; round < 10; ++round) {
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SubBytes(state);
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ShiftRows(state);
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MixColumns(state);
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AddRoundKey(round, state, RoundKey);
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}
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// 最后一轮（无MixColumns）
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SubBytes(state);
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ShiftRows(state);
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AddRoundKey(10, state, RoundKey);
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}
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/* 函数作用：在 AES 有限域中执行两个字节的乘法。 */
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static uint8_t Multiply(uint8_t x, uint8_t y)
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{
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return (((y & 1) * x) ^
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(((y >> 1) & 1) * xtime(x)) ^
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(((y >> 2) & 1) * xtime(xtime(x))) ^
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(((y >> 3) & 1) * xtime(xtime(xtime(x)))) ^
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(((y >> 4) & 1) * xtime(xtime(xtime(xtime(x))))));
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}
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/* 函数作用：使用 AES 逆 S 盒对状态矩阵进行逆字节替换。 */
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static void InvSubBytes(uint8_t* state)
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{
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uint8_t i;
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for (i = 0; i < 16; ++i) {
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state[i] = getSBoxInvert(state[i]);
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}
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}
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/* 函数作用：执行 AES 解密流程中的逆行移位变换。 */
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static void InvShiftRows(uint8_t* state)
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{
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uint8_t temp;
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temp = state[13];
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state[13] = state[9];
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state[9] = state[5];
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state[5] = state[1];
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state[1] = temp;
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temp = state[2];
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state[2] = state[10];
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state[10] = temp;
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temp = state[6];
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state[6] = state[14];
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state[14] = temp;
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temp = state[3];
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state[3] = state[7];
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state[7] = state[11];
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state[11] = state[15];
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state[15] = temp;
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}
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/* 函数作用：执行 AES 解密流程中的逆列混淆变换。 */
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static void InvMixColumns(uint8_t* state)
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{
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uint8_t i;
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uint8_t a, b, c, d;
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for (i = 0; i < 4; ++i) {
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a = state[i * 4 + 0];
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b = state[i * 4 + 1];
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c = state[i * 4 + 2];
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d = state[i * 4 + 3];
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state[i * 4 + 0] = Multiply(a, 0x0e) ^ Multiply(b, 0x0b) ^ Multiply(c, 0x0d) ^ Multiply(d, 0x09);
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state[i * 4 + 1] = Multiply(a, 0x09) ^ Multiply(b, 0x0e) ^ Multiply(c, 0x0b) ^ Multiply(d, 0x0d);
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state[i * 4 + 2] = Multiply(a, 0x0d) ^ Multiply(b, 0x09) ^ Multiply(c, 0x0e) ^ Multiply(d, 0x0b);
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state[i * 4 + 3] = Multiply(a, 0x0b) ^ Multiply(b, 0x0d) ^ Multiply(c, 0x09) ^ Multiply(d, 0x0e);
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}
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}
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/* 函数作用：对 16 字节状态块执行完整 AES 解密。 */
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static void InvCipher(uint8_t* state, const uint8_t* RoundKey)
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{
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uint8_t round;
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AddRoundKey(10, state, RoundKey);
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for (round = 9; ; --round) {
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InvShiftRows(state);
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InvSubBytes(state);
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AddRoundKey(round, state, RoundKey);
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if (round == 0) {
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break;
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}
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InvMixColumns(state);
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}
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}
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// ========== 公开API函数 ==========
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/* 函数作用：初始化 AES 上下文并生成轮密钥。 */
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void AES_init_ctx(struct AES_ctx* ctx, const uint8_t* key)
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{
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KeyExpansion(ctx->RoundKey, key);
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}
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/* 函数作用：初始化 AES 上下文并设置 CBC 模式 IV。 */
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void AES_init_ctx_iv(struct AES_ctx* ctx, const uint8_t* key, const uint8_t* iv)
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{
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KeyExpansion(ctx->RoundKey, key);
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memcpy(ctx->Iv, iv, AES_BLOCKLEN);
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}
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/* 函数作用：对单个 16 字节数据块执行 AES-ECB 加密。 */
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void AES_ECB_encrypt(const struct AES_ctx* ctx, uint8_t* buf)
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{
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Cipher(buf, ctx->RoundKey);
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}
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/* 函数作用：使用 AES-CBC 模式加密指定长度的数据缓冲区。 */
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void AES_CBC_encrypt_buffer(struct AES_ctx* ctx, uint8_t* buf, size_t length)
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{
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size_t i;
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uint8_t j;
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for (i = 0; i < length; i += AES_BLOCKLEN) {
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// XOR with IV/previous ciphertext block
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for (j = 0; j < AES_BLOCKLEN; ++j) {
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buf[i + j] ^= ctx->Iv[j];
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}
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// Encrypt block
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Cipher(buf + i, ctx->RoundKey);
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// Update IV to current ciphertext block
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memcpy(ctx->Iv, buf + i, AES_BLOCKLEN);
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}
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}
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/* 函数作用：对单个 16 字节数据块执行 AES-ECB 解密。 */
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void AES_ECB_decrypt(const struct AES_ctx* ctx, uint8_t* buf)
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{
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InvCipher(buf, ctx->RoundKey);
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}
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/* 函数作用：使用 AES-CBC 模式解密指定长度的数据缓冲区。 */
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void AES_CBC_decrypt_buffer(struct AES_ctx* ctx, uint8_t* buf, size_t length)
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{
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size_t i;
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uint8_t j;
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uint8_t store_next_iv[AES_BLOCKLEN];
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for (i = 0; i < length; i += AES_BLOCKLEN) {
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memcpy(store_next_iv, buf + i, AES_BLOCKLEN);
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InvCipher(buf + i, ctx->RoundKey);
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for (j = 0; j < AES_BLOCKLEN; ++j) {
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buf[i + j] ^= ctx->Iv[j];
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}
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memcpy(ctx->Iv, store_next_iv, AES_BLOCKLEN);
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}
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}
|