summaryrefslogtreecommitdiffstats
path: root/aes.c
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--aes.c422
1 files changed, 211 insertions, 211 deletions
diff --git a/aes.c b/aes.c
index 3ec8fa1..e42ed72 100644
--- a/aes.c
+++ b/aes.c
@@ -3,31 +3,31 @@
This is the implementation of the AES128 algorithm, specifically ECB mode.
The implementation is verified against the test vectors in:
- National Institute of Standards and Technology Special Publication 800-38A 2001 ED
+ National Institute of Standards and Technology Special Publication 800-38A 2001 ED
ECB-AES128
----------
- plain-text:
- 6bc1bee22e409f96e93d7e117393172a
- ae2d8a571e03ac9c9eb76fac45af8e51
- 30c81c46a35ce411e5fbc1191a0a52ef
- f69f2445df4f9b17ad2b417be66c3710
+ plain-text:
+ 6bc1bee22e409f96e93d7e117393172a
+ ae2d8a571e03ac9c9eb76fac45af8e51
+ 30c81c46a35ce411e5fbc1191a0a52ef
+ f69f2445df4f9b17ad2b417be66c3710
- key:
- 2b7e151628aed2a6abf7158809cf4f3c
+ key:
+ 2b7e151628aed2a6abf7158809cf4f3c
- resulting cipher
- 50fe67cc996d32b6da0937e99bafec60
- d9a4dada0892239f6b8b3d7680e15674
- a78819583f0308e7a6bf36b1386abf23
- c6d3416d29165c6fcb8e51a227ba994e
+ resulting cipher
+ 50fe67cc996d32b6da0937e99bafec60
+ d9a4dada0892239f6b8b3d7680e15674
+ a78819583f0308e7a6bf36b1386abf23
+ c6d3416d29165c6fcb8e51a227ba994e
Use aes_encrypt_string() to encrypt or decrypt a string
-NOTE: String length must be evenly divisible by 16byte (str_len % 16 == 0)
- You should pad the end of the string with zeros if this is not the case.
+NOTE: String length must be evenly divisible by 16byte (str_len % 16 == 0)
+ You should pad the end of the string with zeros if this is not the case.
*/
@@ -75,44 +75,44 @@ static uint8_t* Key;
// This can be useful in (embedded) bootloader applications, where ROM is often limited.
static const uint8_t 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,
- 0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0,
- 0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,
- 0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75,
- 0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84,
- 0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,
- 0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8,
- 0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2,
- 0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,
- 0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb,
- 0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79,
- 0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,
- 0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a,
- 0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e,
- 0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,
- 0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16 };
+ //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,
+ 0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0,
+ 0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,
+ 0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75,
+ 0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84,
+ 0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,
+ 0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8,
+ 0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2,
+ 0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,
+ 0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb,
+ 0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79,
+ 0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,
+ 0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a,
+ 0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e,
+ 0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,
+ 0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16 };
// The round constant word array, Rcon[i], contains the values given by
// x to th e power (i-1) being powers of x (x is denoted as {02}) in the field GF(2^8)
// Note that i starts at 1, not 0).
static const uint8_t Rcon[255] = {
- 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a,
- 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39,
- 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a,
- 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8,
- 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef,
- 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc,
- 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b,
- 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3,
- 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94,
- 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20,
- 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35,
- 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f,
- 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04,
- 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63,
- 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd,
- 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb };
+ 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a,
+ 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39,
+ 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a,
+ 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8,
+ 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef,
+ 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc,
+ 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b,
+ 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3,
+ 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94,
+ 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20,
+ 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35,
+ 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f,
+ 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04,
+ 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63,
+ 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd,
+ 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb };
/*****************************************************************************/
@@ -120,101 +120,101 @@ static const uint8_t Rcon[255] = {
/*****************************************************************************/
static uint8_t getSBoxValue(uint8_t num)
{
- return sbox[num];
+ return sbox[num];
}
// This function produces Nb(Nr+1) round keys. The round keys are used in each round to decrypt the states.
static void KeyExpansion()
{
- uint8_t i, j, k;
- uint8_t tempa[4]; // used for the column/row operations
-
- // The first round key is the key itself.
- for(i = 0; i < Nk; ++i)
- {
- RoundKey[ i * 4 ] = Key[ i * 4 ];
- RoundKey[(i * 4) + 1] = Key[(i * 4) + 1];
- RoundKey[(i * 4) + 2] = Key[(i * 4) + 2];
- RoundKey[(i * 4) + 3] = Key[(i * 4) + 3];
- }
-
- // All other round keys are found from the previous round keys.
- for(; (i < (Nb * Nr) + 1); ++i)
- {
- for(j = 0; j < 4; ++j)
- {
- tempa[j]=RoundKey[(i-1) * 4 + j];
- }
- if (i % Nk == 0)
- {
- // This function rotates the 4 bytes in a word to the left once.
- // [a0,a1,a2,a3] becomes [a1,a2,a3,a0]
-
- // Function RotWord()
- {
- k = tempa[0];
- tempa[0] = tempa[1];
- tempa[1] = tempa[2];
- tempa[2] = tempa[3];
- tempa[3] = k;
- }
-
- // SubWord() is a function that takes a four-byte input word and
- // applies the S-box to each of the four bytes to produce an output word.
-
- // Function Subword()
- {
- tempa[0] = getSBoxValue(tempa[0]);
- tempa[1] = getSBoxValue(tempa[1]);
- tempa[2] = getSBoxValue(tempa[2]);
- tempa[3] = getSBoxValue(tempa[3]);
- }
-
- tempa[0] = tempa[0] ^ Rcon[i/Nk];
- }
- else if (Nk > 6 && i % Nk == 4)
- {
- // Function Subword()
- {
- tempa[0] = getSBoxValue(tempa[0]);
- tempa[1] = getSBoxValue(tempa[1]);
- tempa[2] = getSBoxValue(tempa[2]);
- tempa[3] = getSBoxValue(tempa[3]);
- }
- }
- RoundKey[ i * 4 ] = RoundKey[ i - Nk * 4 ] ^ tempa[0];
- RoundKey[(i * 4) + 1] = RoundKey[(i - Nk) * (4 + 1)] ^ tempa[1];
- RoundKey[(i * 4) + 2] = RoundKey[(i - Nk) * (4 + 2)] ^ tempa[2];
- RoundKey[(i * 4) + 3] = RoundKey[(i - Nk) * (4 + 3)] ^ tempa[3];
- }
+ uint8_t i, j, k;
+ uint8_t tempa[4]; // used for the column/row operations
+
+ // The first round key is the key itself.
+ for(i = 0; i < Nk; ++i)
+ {
+ RoundKey[ i * 4 ] = Key[ i * 4 ];
+ RoundKey[(i * 4) + 1] = Key[(i * 4) + 1];
+ RoundKey[(i * 4) + 2] = Key[(i * 4) + 2];
+ RoundKey[(i * 4) + 3] = Key[(i * 4) + 3];
+ }
+
+ // All other round keys are found from the previous round keys.
+ for(; (i < (Nb * Nr) + 1); ++i)
+ {
+ for(j = 0; j < 4; ++j)
+ {
+ tempa[j]=RoundKey[(i-1) * 4 + j];
+ }
+ if (i % Nk == 0)
+ {
+ // This function rotates the 4 bytes in a word to the left once.
+ // [a0,a1,a2,a3] becomes [a1,a2,a3,a0]
+
+ // Function RotWord()
+ {
+ k = tempa[0];
+ tempa[0] = tempa[1];
+ tempa[1] = tempa[2];
+ tempa[2] = tempa[3];
+ tempa[3] = k;
+ }
+
+ // SubWord() is a function that takes a four-byte input word and
+ // applies the S-box to each of the four bytes to produce an output word.
+
+ // Function Subword()
+ {
+ tempa[0] = getSBoxValue(tempa[0]);
+ tempa[1] = getSBoxValue(tempa[1]);
+ tempa[2] = getSBoxValue(tempa[2]);
+ tempa[3] = getSBoxValue(tempa[3]);
+ }
+
+ tempa[0] = tempa[0] ^ Rcon[i/Nk];
+ }
+ else if (Nk > 6 && i % Nk == 4)
+ {
+ // Function Subword()
+ {
+ tempa[0] = getSBoxValue(tempa[0]);
+ tempa[1] = getSBoxValue(tempa[1]);
+ tempa[2] = getSBoxValue(tempa[2]);
+ tempa[3] = getSBoxValue(tempa[3]);
+ }
+ }
+ RoundKey[ i * 4 ] = RoundKey[ i - Nk * 4 ] ^ tempa[0];
+ RoundKey[(i * 4) + 1] = RoundKey[(i - Nk) * (4 + 1)] ^ tempa[1];
+ RoundKey[(i * 4) + 2] = RoundKey[(i - Nk) * (4 + 2)] ^ tempa[2];
+ RoundKey[(i * 4) + 3] = RoundKey[(i - Nk) * (4 + 3)] ^ tempa[3];
+ }
}
// This function adds the round key to state.
// The round key is added to the state by an XOR function.
static void AddRoundKey(uint8_t round)
{
- uint8_t i,j;
- for(i=0;i<4;i++)
- {
- for(j = 0; j < 4; ++j)
- {
- state[j][i] ^= RoundKey[round * Nb * 4 + i * Nb + j];
- }
- }
+ uint8_t i,j;
+ for(i=0;i<4;i++)
+ {
+ for(j = 0; j < 4; ++j)
+ {
+ state[j][i] ^= RoundKey[round * Nb * 4 + i * Nb + j];
+ }
+ }
}
// The SubBytes Function Substitutes the values in the
// state matrix with values in an S-box.
static void SubBytes()
{
- uint8_t i, j;
- for(i = 0; i < 4; ++i)
- {
- for(j = 0; j < 4; ++j)
- {
- state[i][j] = getSBoxValue(state[i][j]);
- }
- }
+ uint8_t i, j;
+ for(i = 0; i < 4; ++i)
+ {
+ for(j = 0; j < 4; ++j)
+ {
+ state[i][j] = getSBoxValue(state[i][j]);
+ }
+ }
}
// The ShiftRows() function shifts the rows in the state to the left.
@@ -222,97 +222,97 @@ static void SubBytes()
// Offset = Row number. So the first row is not shifted.
static void ShiftRows()
{
- uint8_t temp;
-
- // Rotate first row 1 columns to left
- temp = state[1][0];
- state[1][0] = state[1][1];
- state[1][1] = state[1][2];
- state[1][2] = state[1][3];
- state[1][3] = temp;
-
- // Rotate second row 2 columns to left
- temp = state[2][0];
- state[2][0] = state[2][2];
- state[2][2] = temp;
-
- temp = state[2][1];
- state[2][1] = state[2][3];
- state[2][3] = temp;
-
- // Rotate third row 3 columns to left
- temp = state[3][0];
- state[3][0] = state[3][3];
- state[3][3] = state[3][2];
- state[3][2] = state[3][1];
- state[3][1] = temp;
+ uint8_t temp;
+
+ // Rotate first row 1 columns to left
+ temp = state[1][0];
+ state[1][0] = state[1][1];
+ state[1][1] = state[1][2];
+ state[1][2] = state[1][3];
+ state[1][3] = temp;
+
+ // Rotate second row 2 columns to left
+ temp = state[2][0];
+ state[2][0] = state[2][2];
+ state[2][2] = temp;
+
+ temp = state[2][1];
+ state[2][1] = state[2][3];
+ state[2][3] = temp;
+
+ // Rotate third row 3 columns to left
+ temp = state[3][0];
+ state[3][0] = state[3][3];
+ state[3][3] = state[3][2];
+ state[3][2] = state[3][1];
+ state[3][1] = temp;
}
static uint8_t xtime(uint8_t x)
{
- return ((x<<1) ^ (((x>>7) & 1) * 0x1b));
+ return ((x<<1) ^ (((x>>7) & 1) * 0x1b));
}
// MixColumns function mixes the columns of the state matrix
static void MixColumns()
{
- uint8_t i;
- uint8_t Tmp,Tm,t;
- for(i = 0; i < 4; ++i)
- {
- t = state[0][i];
- Tmp = state[0][i] ^ state[1][i] ^ state[2][i] ^ state[3][i] ;
- Tm = state[0][i] ^ state[1][i] ; Tm = xtime(Tm); state[0][i] ^= Tm ^ Tmp ;
- Tm = state[1][i] ^ state[2][i] ; Tm = xtime(Tm); state[1][i] ^= Tm ^ Tmp ;
- Tm = state[2][i] ^ state[3][i] ; Tm = xtime(Tm); state[2][i] ^= Tm ^ Tmp ;
- Tm = state[3][i] ^ t ; Tm = xtime(Tm); state[3][i] ^= Tm ^ Tmp ;
- }
+ uint8_t i;
+ uint8_t Tmp,Tm,t;
+ for(i = 0; i < 4; ++i)
+ {
+ t = state[0][i];
+ Tmp = state[0][i] ^ state[1][i] ^ state[2][i] ^ state[3][i] ;
+ Tm = state[0][i] ^ state[1][i] ; Tm = xtime(Tm); state[0][i] ^= Tm ^ Tmp ;
+ Tm = state[1][i] ^ state[2][i] ; Tm = xtime(Tm); state[1][i] ^= Tm ^ Tmp ;
+ Tm = state[2][i] ^ state[3][i] ; Tm = xtime(Tm); state[2][i] ^= Tm ^ Tmp ;
+ Tm = state[3][i] ^ t ; Tm = xtime(Tm); state[3][i] ^= Tm ^ Tmp ;
+ }
}
// Cipher is the main function that encrypts the PlainText.
static void Cipher()
{
- uint8_t i, j, round = 0;
-
- //Copy the input PlainText to state array.
- for(i = 0; i < 4; ++i)
- {
- for(j = 0; j < 4 ; ++j)
- {
- state[j][i] = in[(i * 4) + j];
- }
- }
-
- // Add the First round key to the state before starting the rounds.
- AddRoundKey(0);
-
- // There will be Nr rounds.
- // The first Nr-1 rounds are identical.
- // These Nr-1 rounds are executed in the loop below.
- for(round = 1; round < Nr; ++round)
- {
- SubBytes();
- ShiftRows();
- MixColumns();
- AddRoundKey(round);
- }
-
- // The last round is given below.
- // The MixColumns function is not here in the last round.
- SubBytes();
- ShiftRows();
- AddRoundKey(Nr);
-
- // The encryption process is over.
- // Copy the state array to output array.
-
- for(i = 0; i < 4; ++i)
- {
- for(j = 0; j < 4; ++j)
- {
- out[(i * 4) + j] = state[j][i];
- }
- }
+ uint8_t i, j, round = 0;
+
+ //Copy the input PlainText to state array.
+ for(i = 0; i < 4; ++i)
+ {
+ for(j = 0; j < 4 ; ++j)
+ {
+ state[j][i] = in[(i * 4) + j];
+ }
+ }
+
+ // Add the First round key to the state before starting the rounds.
+ AddRoundKey(0);
+
+ // There will be Nr rounds.
+ // The first Nr-1 rounds are identical.
+ // These Nr-1 rounds are executed in the loop below.
+ for(round = 1; round < Nr; ++round)
+ {
+ SubBytes();
+ ShiftRows();
+ MixColumns();
+ AddRoundKey(round);
+ }
+
+ // The last round is given below.
+ // The MixColumns function is not here in the last round.
+ SubBytes();
+ ShiftRows();
+ AddRoundKey(Nr);
+
+ // The encryption process is over.
+ // Copy the state array to output array.
+
+ for(i = 0; i < 4; ++i)
+ {
+ for(j = 0; j < 4; ++j)
+ {
+ out[(i * 4) + j] = state[j][i];
+ }
+ }
}
@@ -322,16 +322,16 @@ static void Cipher()
void AES128_ECB(uint8_t* input, uint8_t* key, uint8_t *output)
{
- // Copy the Key and CipherText
- Key = key;
- in = input;
- out = output;
+ // Copy the Key and CipherText
+ Key = key;
+ in = input;
+ out = output;
- // The KeyExpansion routine must be called before encryption.
- KeyExpansion();
+ // The KeyExpansion routine must be called before encryption.
+ KeyExpansion();
- // The next function call encrypts the PlainText with the Key using AES algorithm.
- Cipher();
+ // The next function call encrypts the PlainText with the Key using AES algorithm.
+ Cipher();
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-25 11:19:32 +0100