出處 http://www.codedata.com.tw/social-coding/aes/
// 本程式由陳鍾誠將 jsaes: AES in JavaScript (作者： B. Poettering) 翻譯為 C 語言版，// 來源為 http://point-at-infinity.org/jsaes/，授權為 GNU GPL 授權。#include <stdio.h>#define BYTE unsigned charvoid printBytes(BYTE b[], int len) { int i; for (i=0; i<len; i++) printf("%d ", b[i]); printf("\n");}/******************************************************************************/// The following lookup tables and functions are for internal use only!BYTE AES_Sbox[] = {99,124,119,123,242,107,111,197,48,1,103,43,254,215,171, 118,202,130,201,125,250,89,71,240,173,212,162,175,156,164,114,192,183,253, 147,38,54,63,247,204,52,165,229,241,113,216,49,21,4,199,35,195,24,150,5,154, 7,18,128,226,235,39,178,117,9,131,44,26,27,110,90,160,82,59,214,179,41,227, 47,132,83,209,0,237,32,252,177,91,106,203,190,57,74,76,88,207,208,239,170, 251,67,77,51,133,69,249,2,127,80,60,159,168,81,163,64,143,146,157,56,245, 188,182,218,33,16,255,243,210,205,12,19,236,95,151,68,23,196,167,126,61, 100,93,25,115,96,129,79,220,34,42,144,136,70,238,184,20,222,94,11,219,224, 50,58,10,73,6,36,92,194,211,172,98,145,149,228,121,231,200,55,109,141,213, 78,169,108,86,244,234,101,122,174,8,186,120,37,46,28,166,180,198,232,221, 116,31,75,189,139,138,112,62,181,102,72,3,246,14,97,53,87,185,134,193,29, 158,225,248,152,17,105,217,142,148,155,30,135,233,206,85,40,223,140,161, 137,13,191,230,66,104,65,153,45,15,176,84,187,22};BYTE AES_ShiftRowTab[] = {0,5,10,15,4,9,14,3,8,13,2,7,12,1,6,11};BYTE AES_Sbox_Inv[256];BYTE AES_ShiftRowTab_Inv[16];BYTE AES_xtime[256];void AES_SubBytes(BYTE state[], BYTE sbox[]) { int i; for(i = 0; i < 16; i++) state[i] = sbox[state[i]];}void AES_AddRoundKey(BYTE state[], BYTE rkey[]) { int i; for(i = 0; i < 16; i++) state[i] ^= rkey[i];}void AES_ShiftRows(BYTE state[], BYTE shifttab[]) { BYTE h[16]; memcpy(h, state, 16); int i; for(i = 0; i < 16; i++) state[i] = h[shifttab[i]];}void AES_MixColumns(BYTE state[]) { int i; for(i = 0; i < 16; i += 4) { BYTE s0 = state[i + 0], s1 = state[i + 1]; BYTE s2 = state[i + 2], s3 = state[i + 3]; BYTE h = s0 ^ s1 ^ s2 ^ s3; state[i + 0] ^= h ^ AES_xtime[s0 ^ s1]; state[i + 1] ^= h ^ AES_xtime[s1 ^ s2]; state[i + 2] ^= h ^ AES_xtime[s2 ^ s3]; state[i + 3] ^= h ^ AES_xtime[s3 ^ s0]; }}void AES_MixColumns_Inv(BYTE state[]) { int i; for(i = 0; i < 16; i += 4) { BYTE s0 = state[i + 0], s1 = state[i + 1]; BYTE s2 = state[i + 2], s3 = state[i + 3]; BYTE h = s0 ^ s1 ^ s2 ^ s3; BYTE xh = AES_xtime[h]; BYTE h1 = AES_xtime[AES_xtime[xh ^ s0 ^ s2]] ^ h; BYTE h2 = AES_xtime[AES_xtime[xh ^ s1 ^ s3]] ^ h; state[i + 0] ^= h1 ^ AES_xtime[s0 ^ s1]; state[i + 1] ^= h2 ^ AES_xtime[s1 ^ s2]; state[i + 2] ^= h1 ^ AES_xtime[s2 ^ s3]; state[i + 3] ^= h2 ^ AES_xtime[s3 ^ s0]; }}// AES_Init: initialize the tables needed at runtime. // Call this function before the (first) key expansion.void AES_Init() { int i; for(i = 0; i < 256; i++) AES_Sbox_Inv[AES_Sbox[i]] = i; for(i = 0; i < 16; i++) AES_ShiftRowTab_Inv[AES_ShiftRowTab[i]] = i; for(i = 0; i < 128; i++) { AES_xtime[i] = i << 1; AES_xtime[128 + i] = (i << 1) ^ 0x1b; }}// AES_Done: release memory reserved by AES_Init. // Call this function after the last encryption/decryption operation.void AES_Done() {}/* AES_ExpandKey: expand a cipher key. Depending on the desired encryption strength of 128, 192 or 256 bits 'key' has to be a byte array of length 16, 24 or 32, respectively. The key expansion is done "in place", meaning that the array 'key' is modified.*/ int AES_ExpandKey(BYTE key[], int keyLen) { int kl = keyLen, ks, Rcon = 1, i, j; BYTE temp[4], temp2[4]; switch (kl) { case 16: ks = 16 * (10 + 1); break; case 24: ks = 16 * (12 + 1); break; case 32: ks = 16 * (14 + 1); break; default: printf("AES_ExpandKey: Only key lengths of 16, 24 or 32 bytes allowed!"); } for(i = kl; i < ks; i += 4) { memcpy(temp, &key[i-4], 4); if (i % kl == 0) { temp2[0] = AES_Sbox[temp[1]] ^ Rcon; temp2[1] = AES_Sbox[temp[2]]; temp2[2] = AES_Sbox[temp[3]]; temp2[3] = AES_Sbox[temp[0]]; memcpy(temp, temp2, 4); if ((Rcon <<= 1) >= 256) Rcon ^= 0x11b; } else if ((kl > 24) && (i % kl == 16)) { temp2[0] = AES_Sbox[temp[0]]; temp2[1] = AES_Sbox[temp[1]]; temp2[2] = AES_Sbox[temp[2]]; temp2[3] = AES_Sbox[temp[3]]; memcpy(temp, temp2, 4); } for(j = 0; j < 4; j++) key[i + j] = key[i + j - kl] ^ temp[j]; } return ks;}// AES_Encrypt: encrypt the 16 byte array 'block' with the previously expanded key 'key'.void AES_Encrypt(BYTE block[], BYTE key[], int keyLen) { int l = keyLen, i; printBytes(block, 16); AES_AddRoundKey(block, &key[0]); for(i = 16; i < l - 16; i += 16) { AES_SubBytes(block, AES_Sbox); AES_ShiftRows(block, AES_ShiftRowTab); AES_MixColumns(block); AES_AddRoundKey(block, &key[i]); } AES_SubBytes(block, AES_Sbox); AES_ShiftRows(block, AES_ShiftRowTab); AES_AddRoundKey(block, &key[i]);}// AES_Decrypt: decrypt the 16 byte array 'block' with the previously expanded key 'key'.void AES_Decrypt(BYTE block[], BYTE key[], int keyLen) { int l = keyLen, i; AES_AddRoundKey(block, &key[l - 16]); AES_ShiftRows(block, AES_ShiftRowTab_Inv); AES_SubBytes(block, AES_Sbox_Inv); for(i = l - 32; i >= 16; i -= 16) { AES_AddRoundKey(block, &key[i]); AES_MixColumns_Inv(block); AES_ShiftRows(block, AES_ShiftRowTab_Inv); AES_SubBytes(block, AES_Sbox_Inv); } AES_AddRoundKey(block, &key[0]);}// ===================== test ============================================int main() { int i; AES_Init(); BYTE block[16]; for(i = 0; i < 16; i++) block[i] = 0x11 * i; printf("原始訊息："); printBytes(block, 16); BYTE key[16 * (14 + 1)]; int keyLen = 32, maxKeyLen=16 * (14 + 1), blockLen = 16; for(i = 0; i < keyLen; i++) key[i] = i; printf("原始金鑰："); printBytes(key, keyLen); int expandKeyLen = AES_ExpandKey(key, keyLen); printf("展開金鑰："); printBytes(key, expandKeyLen); AES_Encrypt(block, key, expandKeyLen); printf("加密完後："); printBytes(block, blockLen); AES_Decrypt(block, key, expandKeyLen); printf("解密完後："); printBytes(block, blockLen); AES_Done();}
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