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utils: aes_keyschedule add support for AES-192 and AES-256
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@doegox
doegox committed Nov 21, 2016
1 parent 481c7d2 commit 5976de2
Showing 1 changed file with 36 additions and 15 deletions.
51 changes: 36 additions & 15 deletions utils/aes_keyschedule.c
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Original file line number Diff line number Diff line change
Expand Up @@ -51,29 +51,24 @@
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>


/*****************************************************************************/
/* Defines: */
/*****************************************************************************/
// The number of columns comprising a state in AES. This is a constant in AES. Value=4
#define Nb 4
// The number of 32 bit words in a key.
#define Nk 4
// Key length in bytes [128 bit]
#define KEYLEN 16
// The number of rounds in AES Cipher.
#define Nr 10

/*****************************************************************************/
/* Private variables: */
/*****************************************************************************/
// state - array holding the intermediate results during decryption.
// The array that stores the round keys.
static uint8_t RoundKey[176];
static uint8_t RoundKey[240];

// The Key input to the AES Program
static uint8_t Key[16];
static uint8_t Key[32];

// The lookup-tables are marked const so they can be placed in read-only storage instead of RAM
// The numbers below can be computed dynamically trading ROM for RAM -
Expand Down Expand Up @@ -104,11 +99,15 @@ static const uint8_t Rcon[11] = { 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40


// This function produces Nb(Nr+1) round keys. The round keys are used in each round to decrypt the states.
void KeyExpansion(uint8_t start)
void KeyExpansion(uint8_t start, uint16_t AesSize)
{

uint32_t i, j, k;
uint8_t tempa[4]; // Used for the column/row operations
start *=Nk;
uint8_t Nk = AesSize / 32;
// Nr: The number of rounds in AES Cipher: 10, 12 or 14
uint8_t Nr = Nk+6;
start *=4;
// The first round key is the key itself.
for(i = start; i < (Nk+start); ++i)
{
Expand Down Expand Up @@ -166,7 +165,7 @@ void KeyExpansion(uint8_t start)
RoundKey[i * 4 + 2] = RoundKey[(i - Nk) * 4 + 2] ^ tempa[2];
RoundKey[i * 4 + 3] = RoundKey[(i - Nk) * 4 + 3] ^ tempa[3];
}
for(i=start+3; i>3; i--)
for(i=(Nk+start-1); i>(Nk-1); i--)
{
for(j = 0; j < 4; ++j)
{
Expand Down Expand Up @@ -214,7 +213,7 @@ void KeyExpansion(uint8_t start)
RoundKey[(i - Nk) * 4 + 2] = RoundKey[i * 4 + 2] ^ tempa[2];
RoundKey[(i - Nk) * 4 + 3] = RoundKey[i * 4 + 3] ^ tempa[3];
}
for(j = 0; j < 16*11; ++j)
for(j = 0; j < 16*(Nr+1); ++j)
{
if (j%16==0)
printf("K%02i: ", j/16);
Expand All @@ -239,10 +238,31 @@ int main(int argc, char *argv[])
uint8_t round=0;
if (argc<2) {
printf("Usage: \n%s AES_key_in_hex\n", argv[0]);
printf("%s Round_key_in_hex Round_key_number_between_0_and_10\n", argv[0]);
printf("%s Round_key(s)_in_hex Initial_round_key_number_between_0_and_10#11#13\n", argv[0]);
printf("Examples:\n");
printf("- AES-128: (provide 1 round key)\n");
printf(" %s B1BA2737C83233FE7F7A7DF0FBB01D4A\n", argv[0]);
printf(" %s 97F926D5677B324AC439D77C8B03FDF8 5\n", argv[0]);
printf(" %s FAEF63792F9A97A1FB78C88C4CA7048F 10\n", argv[0]);
printf("- AES-192: (provide 1.5 round keys)\n");
printf(" %s B1BA2737C83233FE7F7A7DF0FBB01D4A7835FA62BE9726A1\n", argv[0]);
printf(" %s D42AAFEB1510F368D8AA1354A707697696D6CC20F7737995 5\n", argv[0]);
printf(" %s 504B601C4EEB5C33B3D208B8E4966BA37B07118538961350 11\n", argv[0]);
printf(" Tip: check if the second half round key is the same as yours. If not => AES-256\n");
printf("- AES-256: (provide 2 round keys)\n");
printf(" %s B1BA2737C83233FE7F7A7DF0FBB01D4A7835FA62BE9726A1BB39F261BAC4729C\n", argv[0]);
printf(" %s F2E96B6FD53C1BBB49D0990E6FF86927DF8F909C21310695C43D2751C133AC12 5\n", argv[0]);
printf(" %s 4D69A4975189FCA00DB0AC8F686EE58C033BE6307A3C13C226DF38591EEAC857 13\n", argv[0]);
return EXIT_FAILURE;
}
for(i = 0; i < 32; i += 2)

uint32_t arglen = strlen(argv[1]);
if( (arglen != 32) && (arglen != 48) && (arglen != 64)) {
printf("Error: AES_key must be 16, 24 or 32-byte long\n");
return EXIT_FAILURE;
}
uint16_t AesSize = arglen * 4;
for(i = 0; i < arglen; i += 2)
{
if(is_hex_char(argv[1][i]) == 0 || is_hex_char(argv[1][i + 1]) == 0)
return EXIT_FAILURE;
Expand All @@ -253,7 +273,8 @@ int main(int argc, char *argv[])
};
Key[ i / 2] = strtoul((const char*)str_bytes, NULL, 16);
}

if (argc > 2)
round = atoi(argv[2]);
KeyExpansion(round);
KeyExpansion(round, AesSize);
}

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