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Add support for using 192-bit and 256-bit keys with AES-GCM

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This adds 192-bit and 256-bit key support to the internal AES
implementation and extends the AES-GCM functions to accept key length to
enable longer AES key use.

Signed-hostap: Jouni Malinen <j@w1.fi>
This commit is contained in:
Jouni Malinen 2012-09-09 12:26:22 +03:00
parent af0963fab4
commit d140db6adf
8 changed files with 258 additions and 65 deletions
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70
src/crypto/aes-internal.c
View file

@ -2,14 +2,13 @@
* AES (Rijndael) cipher
*
* Modifications to public domain implementation:
* - support only 128-bit keys
* - cleanup
* - use C pre-processor to make it easier to change S table access
* - added option (AES_SMALL_TABLES) for reducing code size by about 8 kB at
* cost of reduced throughput (quite small difference on Pentium 4,
* 10-25% when using -O1 or -O2 optimization)
*
* Copyright (c) 2003-2005, Jouni Malinen <j@w1.fi>
* Copyright (c) 2003-2012, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
@ -777,7 +776,7 @@ const u8 rcons[] = {
*
* @return the number of rounds for the given cipher key size.
*/
void rijndaelKeySetupEnc(u32 rk[/*44*/], const u8 cipherKey[])
int rijndaelKeySetupEnc(u32 rk[], const u8 cipherKey[], int keyBits)
{
int i;
u32 temp;
@ -786,14 +785,61 @@ void rijndaelKeySetupEnc(u32 rk[/*44*/], const u8 cipherKey[])
rk[1] = GETU32(cipherKey + 4);
rk[2] = GETU32(cipherKey + 8);
rk[3] = GETU32(cipherKey + 12);
for (i = 0; i < 10; i++) {
temp = rk[3];
rk[4] = rk[0] ^
TE421(temp) ^ TE432(temp) ^ TE443(temp) ^ TE414(temp) ^
RCON(i);
rk[5] = rk[1] ^ rk[4];
rk[6] = rk[2] ^ rk[5];
rk[7] = rk[3] ^ rk[6];
rk += 4;
if (keyBits == 128) {
for (i = 0; i < 10; i++) {
temp = rk[3];
rk[4] = rk[0] ^ TE421(temp) ^ TE432(temp) ^
TE443(temp) ^ TE414(temp) ^ RCON(i);
rk[5] = rk[1] ^ rk[4];
rk[6] = rk[2] ^ rk[5];
rk[7] = rk[3] ^ rk[6];
rk += 4;
}
return 10;
}
rk[4] = GETU32(cipherKey + 16);
rk[5] = GETU32(cipherKey + 20);
if (keyBits == 192) {
for (i = 0; i < 8; i++) {
temp = rk[5];
rk[6] = rk[0] ^ TE421(temp) ^ TE432(temp) ^
TE443(temp) ^ TE414(temp) ^ RCON(i);
rk[7] = rk[1] ^ rk[6];
rk[8] = rk[2] ^ rk[7];
rk[9] = rk[3] ^ rk[8];
if (i == 7)
return 12;
rk[10] = rk[4] ^ rk[9];
rk[11] = rk[5] ^ rk[10];
rk += 6;
}
}
rk[6] = GETU32(cipherKey + 24);
rk[7] = GETU32(cipherKey + 28);
if (keyBits == 256) {
for (i = 0; i < 7; i++) {
temp = rk[7];
rk[8] = rk[0] ^ TE421(temp) ^ TE432(temp) ^
TE443(temp) ^ TE414(temp) ^ RCON(i);
rk[9] = rk[1] ^ rk[8];
rk[10] = rk[2] ^ rk[9];
rk[11] = rk[3] ^ rk[10];
if (i == 6)
return 14;
temp = rk[11];
rk[12] = rk[4] ^ TE411(temp) ^ TE422(temp) ^
TE433(temp) ^ TE444(temp);
rk[13] = rk[5] ^ rk[12];
rk[14] = rk[6] ^ rk[13];
rk[15] = rk[7] ^ rk[14];
rk += 8;
}
}
return -1;
}