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Use xorbufout in chacha

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This commit is contained in:
Juliusz Sosinowicz
2023-03-22 18:48:16 +01:00
parent 8fe321d5be
commit aeb4338085
1 changed files with 28 additions and 42 deletions
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70
wolfcrypt/src/chacha.c
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@ -202,15 +202,12 @@ int wc_Chacha_SetKey(ChaCha* ctx, const byte* key, word32 keySz)
/**
* Converts word into bytes with rotations having been done.
*/
static WC_INLINE void wc_Chacha_wordtobyte(word32 output[CHACHA_CHUNK_WORDS],
const word32 input[CHACHA_CHUNK_WORDS])
static WC_INLINE void wc_Chacha_wordtobyte(word32 x[CHACHA_CHUNK_WORDS],
word32 state[CHACHA_CHUNK_WORDS])
{
word32 x[CHACHA_CHUNK_WORDS];
word32 i;
for (i = 0; i < CHACHA_CHUNK_WORDS; i++) {
x[i] = input[i];
}
XMEMCPY(x, state, CHACHA_CHUNK_BYTES);
for (i = (ROUNDS); i > 0; i -= 2) {
QUARTERROUND(0, 4, 8, 12)
@ -224,11 +221,8 @@ static WC_INLINE void wc_Chacha_wordtobyte(word32 output[CHACHA_CHUNK_WORDS],
}
for (i = 0; i < CHACHA_CHUNK_WORDS; i++) {
x[i] = PLUS(x[i], input[i]);
}
for (i = 0; i < CHACHA_CHUNK_WORDS; i++) {
output[i] = LITTLE32(x[i]);
x[i] = PLUS(x[i], state[i]);
x[i] = LITTLE32(x[i]);
}
}
@ -334,36 +328,33 @@ extern void chacha_encrypt_avx2(ChaCha* ctx, const byte* m, byte* c,
static void wc_Chacha_encrypt_bytes(ChaCha* ctx, const byte* m, byte* c,
word32 bytes)
{
byte* output;
word32 temp[CHACHA_CHUNK_WORDS]; /* used to make sure aligned */
word32 i;
union {
byte state[CHACHA_CHUNK_BYTES];
word32 state32[CHACHA_CHUNK_WORDS];
wolfssl_word align_word; /* align for xorbufout */
} tmp;
/* handle left overs */
if (bytes > 0 && ctx->left > 0) {
wc_Chacha_wordtobyte(temp, ctx->X); /* recreate the stream */
output = (byte*)temp + CHACHA_CHUNK_BYTES - ctx->left;
for (i = 0; i < bytes && i < ctx->left; i++) {
c[i] = (byte)(m[i] ^ output[i]);
}
ctx->left -= i;
word32 processed = min(bytes, ctx->left);
wc_Chacha_wordtobyte(tmp.state32, ctx->X); /* recreate the stream */
xorbufout(c, m, tmp.state + CHACHA_CHUNK_BYTES - ctx->left, processed);
ctx->left -= processed;
/* Used up all of the stream that was left, increment the counter */
if (ctx->left == 0) {
ctx->X[CHACHA_MATRIX_CNT_IV] =
PLUSONE(ctx->X[CHACHA_MATRIX_CNT_IV]);
}
bytes -= i;
c += i;
m += i;
bytes -= processed;
c += processed;
m += processed;
}
output = (byte*)temp;
while (bytes >= CHACHA_CHUNK_BYTES) {
wc_Chacha_wordtobyte(temp, ctx->X);
wc_Chacha_wordtobyte(tmp.state32, ctx->X);
ctx->X[CHACHA_MATRIX_CNT_IV] = PLUSONE(ctx->X[CHACHA_MATRIX_CNT_IV]);
for (i = 0; i < CHACHA_CHUNK_BYTES; ++i) {
c[i] = (byte)(m[i] ^ output[i]);
}
xorbufout(c, m, tmp.state, CHACHA_CHUNK_BYTES);
bytes -= CHACHA_CHUNK_BYTES;
c += CHACHA_CHUNK_BYTES;
m += CHACHA_CHUNK_BYTES;
@ -373,11 +364,9 @@ static void wc_Chacha_encrypt_bytes(ChaCha* ctx, const byte* m, byte* c,
/* in this case there will always be some left over since bytes is less
* than CHACHA_CHUNK_BYTES, so do not increment counter after getting
* stream in order for the stream to be recreated on next call */
wc_Chacha_wordtobyte(temp, ctx->X);
for (i = 0; i < bytes; ++i) {
c[i] = m[i] ^ output[i];
}
ctx->left = CHACHA_CHUNK_BYTES - i;
wc_Chacha_wordtobyte(tmp.state32, ctx->X);
xorbufout(c, m, tmp.state, bytes);
ctx->left = CHACHA_CHUNK_BYTES - bytes;
}
}
@ -394,17 +383,14 @@ int wc_Chacha_Process(ChaCha* ctx, byte* output, const byte* input,
/* handle left overs */
if (msglen > 0 && ctx->left > 0) {
byte* out;
word32 i;
word32 processed = min(msglen, ctx->left);
out = (byte*)ctx->over + CHACHA_CHUNK_BYTES - ctx->left;
for (i = 0; i < msglen && i < ctx->left; i++) {
output[i] = (byte)(input[i] ^ out[i]);
}
ctx->left -= i;
msglen -= i;
output += i;
input += i;
xorbufout(output, input, out, processed);
ctx->left -= processed;
msglen -= processed;
output += processed;
input += processed;
}
if (msglen == 0) {