有些單片機沒有AES硬件外設，但是要實現AES加密和解密，就需要通過軟件來實現了。附件是AES的C語言實現。加密和解密封裝成下面兩個函數。1、加密函數
void inv_cipher(uint8 *in, uint8 *out, uint8 *key)
*in是用戶加密前的數據；*out是用戶加密后的數據；*key是128位的密鑰
2、解密函數
void cipher(uint8 *in, uint8 *out, uint8 *key)
*in是用戶解密前的數據；*out是用戶解密后的數據；*key是128位的密鑰
C語言源程序如下:
- #include <stdio.h>
- #include <stdlib.h>
- #include "soft_AES.h"
- //Addition in GF(2^8)
- uint8 gadd(uint8 a, uint8 b) {
- return a^b;
- }
- //Subtraction in GF(2^8)
- uint8 gsub(uint8 a, uint8 b) {
- return a^b;
- }
- //Multiplication in GF(2^8)
- //正向列混淆
- uint8 gmult(uint8 a, uint8 b) {
- uint8 p = 0, i = 0, hbs = 0;
- for (i = 0; i < 8; i++) {
- if (b & 1) {
- p ^= a;
- }
- hbs = a & 0x80;
- a <<= 1;
- if (hbs) a ^= 0x1b; // 0000 0001 0001 1011
- b >>= 1;
- }
- return (uint8)p;
- }
- //Addition of 4 byte words
- //添加一個字
- void coef_add(uint8 a[], uint8 b[], uint8 d[]) {
- d[0] = a[0]^b[0];
- d[1] = a[1]^b[1];
- d[2] = a[2]^b[2];
- d[3] = a[3]^b[3];
- }
- //Multiplication of 4 byte words
- void coef_mult(uint8 *a, uint8 *b, uint8 *d) {
- d[0] = gmult(a[0],b[0])^gmult(a[3],b[1])^gmult(a[2],b[2])^gmult(a[1],b[3]);
- d[1] = gmult(a[1],b[0])^gmult(a[0],b[1])^gmult(a[3],b[2])^gmult(a[2],b[3]);
- d[2] = gmult(a[2],b[0])^gmult(a[1],b[1])^gmult(a[0],b[2])^gmult(a[3],b[3]);
- d[3] = gmult(a[3],b[0])^gmult(a[2],b[1])^gmult(a[1],b[2])^gmult(a[0],b[3]);
- }
-
- uint8 K;//The cipher Key.
- #define Nb 4//Number of columns (32-bit words) comprising the State. For this standard, Nb = 4.
- uint8 Nk;// * Number of 32-bit words comprising the Cipher Key. For this standard, Nk = 4, 6, or 8
- uint8 Nr;// Number of rounds, which is a function of Nk and Nb (which is fixed). For this standard, Nr = 10, 12, or 14
- //S-box transformation table
- static uint8 s_box[256] = {
- // 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
- //Inverse S-box transformation table
- static uint8 inv_s_box[256] = {
- // 0 1 2 3 4 5 6 7 8 9 a b c d e f
- 0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb, // 0
- 0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb, // 1
- 0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e, // 2
- 0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25, // 3
- 0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92, // 4
- 0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84, // 5
- 0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06, // 6
- 0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b, // 7
- 0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73, // 8
- 0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e, // 9
- 0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b, // a
- 0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4, // b
- 0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f, // c
- 0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef, // d
- 0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61, // e
- 0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d};// f
- //Generates the round constant Rcon[i]
- uint8 R[] = {0x02, 0x00, 0x00, 0x00};
-
- uint8 * Rcon(uint8 i) {
-
- if (i == 1) {
- R[0] = 0x01; // x^(1-1) = x^0 = 1
- } else if (i > 1) {
- R[0] = 0x02;
- i--;
- while (i-1 > 0) {
- R[0] = gmult(R[0], 0x02);
- i--;
- }
- }
-
- return R;
- }
- /*
- * Transformation in the Cipher and Inverse Cipher in which a Round
- * Key is added to the State using an XOR operation. The length of a
- * Round Key equals the size of the State (i.e., for Nb = 4, the Round
- * Key length equals 128 bits/16 bytes).
- */
- //輪密鑰加,128位的State按位與 128位的密鑰異或
- void add_round_key(uint8 *state, uint8 *w, uint8 r) {
-
- uint8 c;
-
- for (c = 0; c < Nb; c++) {
- state[Nb*0+c] = state[Nb*0+c]^w[4*Nb*r+4*c+0]; //debug, so it works for Nb !=4
- state[Nb*1+c] = state[Nb*1+c]^w[4*Nb*r+4*c+1];
- state[Nb*2+c] = state[Nb*2+c]^w[4*Nb*r+4*c+2];
- state[Nb*3+c] = state[Nb*3+c]^w[4*Nb*r+4*c+3];
- }
- }
- /*
- * Transformation in the Cipher that takes all of the columns of the
- * State and mixes their data (independently of one another) to
- * produce new columns.
- */
- //列混合
- void mix_columns(uint8 *state) {
- uint8 a[] = {0x02, 0x01, 0x01, 0x03}; // a(x) = {02} + {01}x + {01}x2 + {03}x3
- uint8 i, j, col[4], res[4];
- for (j = 0; j < Nb; j++) {
- for (i = 0; i < 4; i++) {
- col[i] = state[Nb*i+j];
- }
- coef_mult(a, col, res);
- for (i = 0; i < 4; i++) {
- state[Nb*i+j] = res[i];
- }
- }
- }
- /*
- * Transformation in the Inverse Cipher that is the inverse of
- * MixColumns().
- */
- //逆列混合
- void inv_mix_columns(uint8 *state) {
- uint8 a[] = {0x0e, 0x09, 0x0d, 0x0b}; // a(x) = {0e} + {09}x + {0d}x2 + {0b}x3
- uint8 i, j, col[4], res[4];
- for (j = 0; j < Nb; j++) {
- for (i = 0; i < 4; i++) {
- col[i] = state[Nb*i+j];
- }
- coef_mult(a, col, res);
- for (i = 0; i < 4; i++) {
- state[Nb*i+j] = res[i];
- }
- }
- }
- /*
- * Transformation in the Cipher that processes the State by cyclically
- * shifting the last three rows of the State by different offsets.
- */
- //行移位
- void shift_rows(uint8 *state) {
- uint8 i, k, s, tmp;
- for (i = 1; i < 4; i++) {
- // shift(1,4)=1; shift(2,4)=2; shift(3,4)=3
- // shift(r, 4) = r;
- s = 0;
- while (s < i) {
- tmp = state[Nb*i+0];
-
- for (k = 1; k < Nb; k++) {
- state[Nb*i+k-1] = state[Nb*i+k];
- }
- state[Nb*i+Nb-1] = tmp;
- s++;
- }
- }
- }
- /*
- * Transformation in the Inverse Cipher that is the inverse of
- * ShiftRows().
- */
- //逆行移位
- void inv_shift_rows(uint8 *state) {
- uint8 i, k, s, tmp;
- for (i = 1; i < 4; i++) {
- s = 0;
- while (s < i) {
- tmp = state[Nb*i+Nb-1];
-
- for (k = Nb-1; k > 0; k--) {
- state[Nb*i+k] = state[Nb*i+k-1];
- }
- state[Nb*i+0] = tmp;
- s++;
- }
- }
- }
- /*
- * Transformation in the Cipher that processes the State using a non-
- * linear byte substitution table (S-box) that operates on each of the
- * State bytes independently.
- */
- //字節代替
- void sub_bytes(uint8 *state) {
- uint8 i, j;
- uint8 row, col;
- for (i = 0; i < 4; i++) {
- for (j = 0; j < Nb; j++) {
- row = (state[Nb*i+j] & 0xf0) >> 4;
- col = state[Nb*i+j] & 0x0f;
- state[Nb*i+j] = s_box[16*row+col];
- }
- }
- }
- /*
- * Transformation in the Inverse Cipher that is the inverse of
- * SubBytes().
- */
- //逆字節代替
- void inv_sub_bytes(uint8 *state) {
- uint8 i, j;
- uint8 row, col;
- for (i = 0; i < 4; i++) {
- for (j = 0; j < Nb; j++) {
- row = (state[Nb*i+j] & 0xf0) >> 4;
- col = state[Nb*i+j] & 0x0f;
- state[Nb*i+j] = inv_s_box[16*row+col];
- }
- }
- }
- /*
- * Function used in the Key Expansion routine that takes a four-byte
- * input word and applies an S-box to each of the four bytes to
- * produce an output word.
- */
- //S盒變換
- void sub_word(uint8 *w) {
- uint8 i;
- for (i = 0; i < 4; i++) {
- w[i] = s_box[16*((w[i] & 0xf0) >> 4) + (w[i] & 0x0f)];
- }
- }
- /*
- * Function used in the Key Expansion routine that takes a four-byte
- * word and performs a cyclic permutation.
- */
- //左移
- void rot_word(uint8 *w) {
- uint8 tmp;
- uint8 i;
- tmp = w[0];
- for (i = 0; i < 3; i++) {
- w[i] = w[i+1];
- }
- w[3] = tmp;
- }
- /*
- * Key Expansion
- */
- //擴展密鑰
- void key_expansion(uint8 *key, uint8 *w) {
- uint8 tmp[4];
- uint8 i;
- uint8 len = Nb*(Nr+1);
- for (i = 0; i < Nk; i++) {
- w[4*i+0] = key[4*i+0];
- w[4*i+1] = key[4*i+1];
- w[4*i+2] = key[4*i+2];
- w[4*i+3] = key[4*i+3];
- }
- for (i = Nk; i < len; i++) {
- tmp[0] = w[4*(i-1)+0];
- tmp[1] = w[4*(i-1)+1];
- tmp[2] = w[4*(i-1)+2];
- tmp[3] = w[4*(i-1)+3];
- if (i%Nk == 0) {
- rot_word(tmp);
- sub_word(tmp);
- coef_add(tmp, Rcon(i/Nk), tmp);
- } else if (Nk > 6 && i%Nk == 4) {
- sub_word(tmp);
- }
- w[4*i+0] = w[4*(i-Nk)+0]^tmp[0];
- w[4*i+1] = w[4*(i-Nk)+1]^tmp[1];
- w[4*i+2] = w[4*(i-Nk)+2]^tmp[2];
- w[4*i+3] = w[4*(i-Nk)+3]^tmp[3];
- }
- }
- //加密函數
- void cipher(uint8 *in, uint8 *out, uint8 *key) {
- uint8 state[4*Nb];
- uint8 r, i, j;
- uint8 *w;
-
- Nk = 4;
- Nr = 10;//輪數為10
-
- w = malloc(Nb*(Nr+1)*4);//申請擴展密鑰長度為176
- key_expansion(key, w);//擴展密鑰
- for (i = 0; i < 4; i++) {
- for (j = 0; j < Nb; j++) {
- state[Nb*i+j] = in[i+4*j];
- }
- }
- add_round_key(state, w, 0);//輪密鑰加
- for (r = 1; r < Nr; r++) {
- sub_bytes(state);//字節代替
- shift_rows(state);//行移位
- mix_columns(state);//列混合
- add_round_key(state, w, r);//輪密鑰加
- }
- //最后一輪只執行3個階段
- sub_bytes(state);
- shift_rows(state);
- add_round_key(state, w, Nr);
- for (i = 0; i < 4; i++) {
- for (j = 0; j < Nb; j++) {
- out[i+4*j] = state[Nb*i+j];
- }
- }
- }
- //解密函數
- void inv_cipher(uint8 *in, uint8 *out, uint8 *key) {
- uint8 state[4*Nb];
- uint8 r, i, j;
- uint8 *w;
-
- Nk = 4;
- Nr = 10;//輪數為10
-
- w = malloc(Nb*(Nr+1)*4);//申請擴展密鑰長度為176
- key_expansion(key, w);//擴展密鑰
- for (i = 0; i < 4; i++) {
- for (j = 0; j < Nb; j++) {
- state[Nb*i+j] = in[i+4*j];
- }
- }
- add_round_key(state, w, Nr);//輪密鑰加
- for (r = Nr-1; r >= 1; r--) {
- inv_shift_rows(state);//逆行移位
- inv_sub_bytes(state);//逆字節代替
- add_round_key(state, w, r);//輪密鑰加
- inv_mix_columns(state);//逆列混合
- }
- inv_shift_rows(state);//逆行移位
- inv_sub_bytes(state);//逆字節代替
- add_round_key(state, w, 0);//輪密鑰加
- for (i = 0; i < 4; i++) {
- for (j = 0; j < Nb; j++) {
- out[i+4*j] = state[Nb*i+j];
- }
- }
- }
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AES加密和解密的C語言實現
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