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Refactor of the ChaCha hard coded variables.

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This commit is contained in:
David Garske
2016-03-16 13:36:44 -07:00
parent 47491e6c22
commit 473ea567bd
2 changed files with 29 additions and 20 deletions
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39
wolfcrypt/src/chacha.c
View File

@ -77,12 +77,12 @@
*/
int wc_Chacha_SetIV(ChaCha* ctx, const byte* inIv, word32 counter)
{
word32 temp[3]; /* used for alignment of memory */
word32 temp[CHACHA_IV_WORDS];/* used for alignment of memory */
#ifdef CHACHA_AEAD_TEST
word32 i;
printf("NONCE : ");
for (i = 0; i < 12; i++) {
for (i = 0; i < CHACHA_IV_BYTES; i++) {
printf("%02x", inIv[i]);
}
printf("\n\n");
@ -91,12 +91,12 @@ int wc_Chacha_SetIV(ChaCha* ctx, const byte* inIv, word32 counter)
if (ctx == NULL)
return BAD_FUNC_ARG;
XMEMCPY(temp, inIv, 12);
XMEMCPY(temp, inIv, CHACHA_IV_BYTES);
ctx->X[12] = counter; /* block counter */
ctx->X[13] = LITTLE32(temp[0]); /* fixed variable from nonce */
ctx->X[14] = LITTLE32(temp[1]); /* counter from nonce */
ctx->X[15] = LITTLE32(temp[2]); /* counter from nonce */
ctx->X[CHACHA_IV_BYTES+0] = counter; /* block counter */
ctx->X[CHACHA_IV_BYTES+1] = LITTLE32(temp[0]); /* fixed variable from nonce */
ctx->X[CHACHA_IV_BYTES+2] = LITTLE32(temp[1]); /* counter from nonce */
ctx->X[CHACHA_IV_BYTES+3] = LITTLE32(temp[2]); /* counter from nonce */
return 0;
}
@ -174,12 +174,13 @@ int wc_Chacha_SetKey(ChaCha* ctx, const byte* key, word32 keySz)
/**
* Converts word into bytes with rotations having been done.
*/
static INLINE void wc_Chacha_wordtobyte(word32 output[16], const word32 input[16])
static INLINE void wc_Chacha_wordtobyte(word32 output[CHACHA_CHUNK_WORDS],
const word32 input[CHACHA_CHUNK_WORDS])
{
word32 x[16];
word32 x[CHACHA_CHUNK_WORDS];
word32 i;
for (i = 0; i < 16; i++) {
for (i = 0; i < CHACHA_CHUNK_WORDS; i++) {
x[i] = input[i];
}
@ -194,11 +195,11 @@ static INLINE void wc_Chacha_wordtobyte(word32 output[16], const word32 input[16
QUARTERROUND(3, 4, 9, 14)
}
for (i = 0; i < 16; i++) {
for (i = 0; i < CHACHA_CHUNK_WORDS; i++) {
x[i] = PLUS(x[i], input[i]);
}
for (i = 0; i < 16; i++) {
for (i = 0; i < CHACHA_CHUNK_WORDS; i++) {
output[i] = LITTLE32(x[i]);
}
}
@ -210,7 +211,7 @@ static void wc_Chacha_encrypt_bytes(ChaCha* ctx, const byte* m, byte* c,
word32 bytes)
{
byte* output;
word32 temp[16]; /* used to make sure aligned */
word32 temp[CHACHA_CHUNK_WORDS]; /* used to make sure aligned */
word32 i;
output = (byte*)temp;
@ -218,19 +219,19 @@ static void wc_Chacha_encrypt_bytes(ChaCha* ctx, const byte* m, byte* c,
if (!bytes) return;
for (;;) {
wc_Chacha_wordtobyte(temp, ctx->X);
ctx->X[12] = PLUSONE(ctx->X[12]);
if (bytes <= 64) {
ctx->X[CHACHA_IV_BYTES] = PLUSONE(ctx->X[CHACHA_IV_BYTES]);
if (bytes <= CHACHA_CHUNK_BYTES) {
for (i = 0; i < bytes; ++i) {
c[i] = m[i] ^ output[i];
}
return;
}
for (i = 0; i < 64; ++i) {
for (i = 0; i < CHACHA_CHUNK_BYTES; ++i) {
c[i] = m[i] ^ output[i];
}
bytes -= 64;
c += 64;
m += 64;
bytes -= CHACHA_CHUNK_BYTES;
c += CHACHA_CHUNK_BYTES;
m += CHACHA_CHUNK_BYTES;
}
}

10
wolfssl/wolfcrypt/chacha.h
View File

@ -30,12 +30,20 @@
extern "C" {
#endif
/* Size of the IV */
#define CHACHA_IV_WORDS 3
#define CHACHA_IV_BYTES (CHACHA_IV_WORDS * sizeof(word32))
/* Size of ChaCha chunks */
#define CHACHA_CHUNK_WORDS 16
#define CHACHA_CHUNK_BYTES (CHACHA_CHUNK_WORDS * sizeof(word32))
enum {
CHACHA_ENC_TYPE = 7 /* cipher unique type */
};
typedef struct ChaCha {
word32 X[16]; /* state of cipher */
word32 X[CHACHA_CHUNK_WORDS]; /* state of cipher */
} ChaCha;
/**