?? sshaes.c
字號:
LASTWORD(0);
LASTWORD(1);
LASTWORD(2);
LASTWORD(3);
LASTWORD(4);
LASTWORD(5);
LASTWORD(6);
LASTWORD(7);
MOVEWORD(0);
MOVEWORD(1);
MOVEWORD(2);
MOVEWORD(3);
MOVEWORD(4);
MOVEWORD(5);
MOVEWORD(6);
MOVEWORD(7);
ADD_ROUND_KEY_8;
}
#undef MAKEWORD
#undef LASTWORD
/*
* Set up an AESContext. `keylen' and `blocklen' are measured in
* bytes; each can be either 16 (128-bit), 24 (192-bit), or 32
* (256-bit).
*/
static void aes_setup(AESContext * ctx, int blocklen,
unsigned char *key, int keylen)
{
int i, j, Nk, rconst;
assert(blocklen == 16 || blocklen == 24 || blocklen == 32);
assert(keylen == 16 || keylen == 24 || keylen == 32);
/*
* Basic parameters. Words per block, words in key, rounds.
*/
Nk = keylen / 4;
ctx->Nb = blocklen / 4;
ctx->Nr = 6 + (ctx->Nb > Nk ? ctx->Nb : Nk);
/*
* Assign core-function pointers.
*/
if (ctx->Nb == 8)
ctx->encrypt = aes_encrypt_nb_8, ctx->decrypt = aes_decrypt_nb_8;
else if (ctx->Nb == 6)
ctx->encrypt = aes_encrypt_nb_6, ctx->decrypt = aes_decrypt_nb_6;
else if (ctx->Nb == 4)
ctx->encrypt = aes_encrypt_nb_4, ctx->decrypt = aes_decrypt_nb_4;
/*
* Now do the key setup itself.
*/
rconst = 1;
for (i = 0; i < (ctx->Nr + 1) * ctx->Nb; i++) {
if (i < Nk)
ctx->keysched[i] = GET_32BIT_MSB_FIRST(key + 4 * i);
else {
word32 temp = ctx->keysched[i - 1];
if (i % Nk == 0) {
int a, b, c, d;
a = (temp >> 16) & 0xFF;
b = (temp >> 8) & 0xFF;
c = (temp >> 0) & 0xFF;
d = (temp >> 24) & 0xFF;
temp = Sbox[a] ^ rconst;
temp = (temp << 8) | Sbox[b];
temp = (temp << 8) | Sbox[c];
temp = (temp << 8) | Sbox[d];
rconst = mulby2(rconst);
} else if (i % Nk == 4 && Nk > 6) {
int a, b, c, d;
a = (temp >> 24) & 0xFF;
b = (temp >> 16) & 0xFF;
c = (temp >> 8) & 0xFF;
d = (temp >> 0) & 0xFF;
temp = Sbox[a];
temp = (temp << 8) | Sbox[b];
temp = (temp << 8) | Sbox[c];
temp = (temp << 8) | Sbox[d];
}
ctx->keysched[i] = ctx->keysched[i - Nk] ^ temp;
}
}
/*
* Now prepare the modified keys for the inverse cipher.
*/
for (i = 0; i <= ctx->Nr; i++) {
for (j = 0; j < ctx->Nb; j++) {
word32 temp;
temp = ctx->keysched[(ctx->Nr - i) * ctx->Nb + j];
if (i != 0 && i != ctx->Nr) {
/*
* Perform the InvMixColumn operation on i. The D
* tables give the result of InvMixColumn applied
* to Sboxinv on individual bytes, so we should
* compose Sbox with the D tables for this.
*/
int a, b, c, d;
a = (temp >> 24) & 0xFF;
b = (temp >> 16) & 0xFF;
c = (temp >> 8) & 0xFF;
d = (temp >> 0) & 0xFF;
temp = D0[Sbox[a]];
temp ^= D1[Sbox[b]];
temp ^= D2[Sbox[c]];
temp ^= D3[Sbox[d]];
}
ctx->invkeysched[i * ctx->Nb + j] = temp;
}
}
}
static void aes_encrypt(AESContext * ctx, word32 * block)
{
ctx->encrypt(ctx, block);
}
static void aes_decrypt(AESContext * ctx, word32 * block)
{
ctx->decrypt(ctx, block);
}
static void aes_encrypt_cbc(unsigned char *blk, int len, AESContext * ctx)
{
word32 iv[4];
int i;
assert((len & 15) == 0);
memcpy(iv, ctx->iv, sizeof(iv));
while (len > 0) {
for (i = 0; i < 4; i++)
iv[i] ^= GET_32BIT_MSB_FIRST(blk + 4 * i);
aes_encrypt(ctx, iv);
for (i = 0; i < 4; i++)
PUT_32BIT_MSB_FIRST(blk + 4 * i, iv[i]);
blk += 16;
len -= 16;
}
memcpy(ctx->iv, iv, sizeof(iv));
}
static void aes_decrypt_cbc(unsigned char *blk, int len, AESContext * ctx)
{
word32 iv[4], x[4], ct[4];
int i;
assert((len & 15) == 0);
memcpy(iv, ctx->iv, sizeof(iv));
while (len > 0) {
for (i = 0; i < 4; i++)
x[i] = ct[i] = GET_32BIT_MSB_FIRST(blk + 4 * i);
aes_decrypt(ctx, x);
for (i = 0; i < 4; i++) {
PUT_32BIT_MSB_FIRST(blk + 4 * i, iv[i] ^ x[i]);
iv[i] = ct[i];
}
blk += 16;
len -= 16;
}
memcpy(ctx->iv, iv, sizeof(iv));
}
static void *aes_make_context(void)
{
return snew(AESContext);
}
static void aes_free_context(void *handle)
{
sfree(handle);
}
static void aes128_key(void *handle, unsigned char *key)
{
AESContext *ctx = (AESContext *)handle;
aes_setup(ctx, 16, key, 16);
}
static void aes192_key(void *handle, unsigned char *key)
{
AESContext *ctx = (AESContext *)handle;
aes_setup(ctx, 16, key, 24);
}
static void aes256_key(void *handle, unsigned char *key)
{
AESContext *ctx = (AESContext *)handle;
aes_setup(ctx, 16, key, 32);
}
static void aes_iv(void *handle, unsigned char *iv)
{
AESContext *ctx = (AESContext *)handle;
int i;
for (i = 0; i < 4; i++)
ctx->iv[i] = GET_32BIT_MSB_FIRST(iv + 4 * i);
}
static void aes_ssh2_encrypt_blk(void *handle, unsigned char *blk, int len)
{
AESContext *ctx = (AESContext *)handle;
aes_encrypt_cbc(blk, len, ctx);
}
static void aes_ssh2_decrypt_blk(void *handle, unsigned char *blk, int len)
{
AESContext *ctx = (AESContext *)handle;
aes_decrypt_cbc(blk, len, ctx);
}
void aes256_encrypt_pubkey(unsigned char *key, unsigned char *blk, int len)
{
AESContext ctx;
aes_setup(&ctx, 16, key, 32);
memset(ctx.iv, 0, sizeof(ctx.iv));
aes_encrypt_cbc(blk, len, &ctx);
memset(&ctx, 0, sizeof(ctx));
}
void aes256_decrypt_pubkey(unsigned char *key, unsigned char *blk, int len)
{
AESContext ctx;
aes_setup(&ctx, 16, key, 32);
memset(ctx.iv, 0, sizeof(ctx.iv));
aes_decrypt_cbc(blk, len, &ctx);
memset(&ctx, 0, sizeof(ctx));
}
static const struct ssh2_cipher ssh_aes128 = {
aes_make_context, aes_free_context, aes_iv, aes128_key,
aes_ssh2_encrypt_blk, aes_ssh2_decrypt_blk,
"aes128-cbc",
16, 128, "AES-128"
};
static const struct ssh2_cipher ssh_aes192 = {
aes_make_context, aes_free_context, aes_iv, aes192_key,
aes_ssh2_encrypt_blk, aes_ssh2_decrypt_blk,
"aes192-cbc",
16, 192, "AES-192"
};
static const struct ssh2_cipher ssh_aes256 = {
aes_make_context, aes_free_context, aes_iv, aes256_key,
aes_ssh2_encrypt_blk, aes_ssh2_decrypt_blk,
"aes256-cbc",
16, 256, "AES-256"
};
static const struct ssh2_cipher ssh_rijndael128 = {
aes_make_context, aes_free_context, aes_iv, aes128_key,
aes_ssh2_encrypt_blk, aes_ssh2_decrypt_blk,
"rijndael128-cbc",
16, 128, "AES-128"
};
static const struct ssh2_cipher ssh_rijndael192 = {
aes_make_context, aes_free_context, aes_iv, aes192_key,
aes_ssh2_encrypt_blk, aes_ssh2_decrypt_blk,
"rijndael192-cbc",
16, 192, "AES-192"
};
static const struct ssh2_cipher ssh_rijndael256 = {
aes_make_context, aes_free_context, aes_iv, aes256_key,
aes_ssh2_encrypt_blk, aes_ssh2_decrypt_blk,
"rijndael256-cbc",
16, 256, "AES-256"
};
static const struct ssh2_cipher ssh_rijndael_lysator = {
aes_make_context, aes_free_context, aes_iv, aes256_key,
aes_ssh2_encrypt_blk, aes_ssh2_decrypt_blk,
"rijndael-cbc@lysator.liu.se",
16, 256, "AES-256"
};
static const struct ssh2_cipher *const aes_list[] = {
&ssh_aes256,
&ssh_rijndael256,
&ssh_rijndael_lysator,
&ssh_aes192,
&ssh_rijndael192,
&ssh_aes128,
&ssh_rijndael128,
};
const struct ssh2_ciphers ssh2_aes = {
sizeof(aes_list) / sizeof(*aes_list),
aes_list
};
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