pilar
Joined: 30 Jan 2008
Posts: 197
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| AES-128 |
 Posted: Mon Jul 16, 2018 11:11 am |
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HI
I'm trying to move this code of AES-128 to CCS for a PIC18F4620, apparently I have no memory problems but the encrypted and decrypted data does not match, someone has managed to make it work, can you give me any suggestions ?
Here is my code:
| Code: | #include <18F4520.h>
#DEVICE ADC=8
#fuses HS,NOWDT,NOPROTECT,NOLVP,NOBROWNOUT
#use delay(clock=20000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7)// RS232 Estándar
const unsigned char sbox[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
// multiply by 2 in the galois field
unsigned char galois_mul2(unsigned char value)
{
signed char temp;
// cast to signed value
temp = (signed char) value;
// if MSB is 1, then this will signed extend and fill the temp variable with 1's
temp = temp >> 7;
// AND with the reduction variable
temp = temp & 0x1b;
// finally shift and reduce the value
return ((value << 1)^temp);
}
// aes encryption function
// It manipulates the state and computes the key schedule on the fly
void aes_encrypt(unsigned char *state, unsigned char *key)
{
unsigned char buf1, buf2, buf3, buf4, round, i;
unsigned char rcon;
// Rcon initial value. All subsequent values are computed.
rcon = 0x01;
// main AES data loop
for (round = 0; round < 10; round++){
//add key + sbox
for (i = 0; i <16; i++){
state[i]=sbox[state[i] ^ key[i]];
}
//shift rows
buf1 = state[1];
state[1] = state[5];
state[5] = state[9];
state[9] = state[13];
state[13] = buf1;
buf1 = state[2];
buf2 = state[6];
state[2] = state[10];
state[6] = state[14];
state[10] = buf1;
state[14] = buf2;
buf1 = state[15];
state[15] = state[11];
state[11] = state[7];
state[7] = state[3];
state[3] = buf1;
//process mixcolumn for all rounds but the last one
if (round < 9) {
for (i=0; i <4; i++){
// compute the current index
buf4 = (i << 2);
buf1 = state[buf4] ^ (state[buf4+1]) ^ (state[buf4+2]) ^ (state[buf4+3]);
buf2 = state[buf4];
buf3 = state[buf4]^(state[buf4+1]); buf3=galois_mul2(buf3); state[buf4] = state[buf4] ^ buf3 ^ buf1;
buf3 = state[buf4+1]^(state[buf4+2]); buf3=galois_mul2(buf3); state[buf4+1] = state[buf4+1] ^ buf3 ^ buf1;
buf3 = state[buf4+3]^buf2; buf3=galois_mul2(buf3); state[buf4+3] = state[buf4+3] ^ buf3 ^ buf1;
}
}
//key schedule
// compute the 16 next round key bytes
key[0] = sbox[key[13]]^key[0]^rcon;
key[1] = sbox[key[14]]^key[1];
key[2] = sbox[key[15]]^key[2];
key[3] = sbox[key[12]]^key[3];
for (i=4; i<16; i++) {
key[i] = key[i] ^ (key[i-4]);
}
// compute the next Rcon value
rcon = galois_mul2(rcon);
}
// process last AddRoundKey
for (i = 0; i <16; i++){
state[i]=state[i] ^ key[i];
printf("%x",state[i]); // Print DATA Encrypt !!!!
}
}
int main( void ){
unsigned char state[] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff};
unsigned char ciphertext[] = {0x69, 0xc4, 0xe0, 0xd8, 0x6a, 0x7b, 0x04, 0x30, 0xd8, 0xcd, 0xb7, 0x80, 0x70, 0xb4, 0xc5, 0x5a};
unsigned char key[] = {0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f};
unsigned char i;
unsigned char err_count = 0;
aes_encrypt(state,key);
for (i=0;i<16;i++) {
if (state[i] != ciphertext[i]) {
err_count++;
}
}
return 0;
} |
The encrypted data must be identical to: ciphertext[] = {0x69, 0xc4, 0xe0, 0xd8, 0x6a, 0x7b, 0x04, 0x30, 0xd8, 0xcd, 0xb7, 0x80, 0x70, 0xb4, 0xc5, 0x5a};
but I'm getting: 0xe1, 0x69, 0x6c, 0x5b, 0x40, 0x46, 0x72, 0xc5, 0x45, 0x26, 0x4a, 0x82, 0x3a, 0x68, 0x35, 0x6f
Last edited by pilar on Tue Jul 17, 2018 10:20 am; edited 2 times in total |
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