static const char sigma[16] = "expand 32-byte k";
static const char tau[16] = "expand 16-byte k";
-void chacha_keysetup(chacha_ctx *x, const uint8_t *k, uint32_t kbits)
-{
+void chacha_keysetup(chacha_ctx *x, const uint8_t *k, uint32_t kbits) {
const char *constants;
x->input[4] = U8TO32_LITTLE(k + 0);
x->input[5] = U8TO32_LITTLE(k + 4);
x->input[6] = U8TO32_LITTLE(k + 8);
x->input[7] = U8TO32_LITTLE(k + 12);
- if (kbits == 256) { /* recommended */
+
+ if(kbits == 256) { /* recommended */
k += 16;
constants = sigma;
- } else { /* kbits == 128 */
+ } else { /* kbits == 128 */
constants = tau;
}
+
x->input[8] = U8TO32_LITTLE(k + 0);
x->input[9] = U8TO32_LITTLE(k + 4);
x->input[10] = U8TO32_LITTLE(k + 8);
x->input[3] = U8TO32_LITTLE(constants + 12);
}
-void chacha_ivsetup(chacha_ctx *x, const uint8_t *iv, const uint8_t *counter)
-{
+void chacha_ivsetup(chacha_ctx *x, const uint8_t *iv, const uint8_t *counter) {
x->input[12] = counter == NULL ? 0 : U8TO32_LITTLE(counter + 0);
x->input[13] = counter == NULL ? 0 : U8TO32_LITTLE(counter + 4);
x->input[14] = U8TO32_LITTLE(iv + 0);
}
void
-chacha_encrypt_bytes(chacha_ctx *x, const uint8_t *m, uint8_t *c, uint32_t bytes)
-{
+chacha_encrypt_bytes(chacha_ctx *x, const uint8_t *m, uint8_t *c, uint32_t bytes) {
uint32_t x0, x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, x13, x14, x15;
uint32_t j0, j1, j2, j3, j4, j5, j6, j7, j8, j9, j10, j11, j12, j13, j14, j15;
uint8_t *ctarget = NULL;
uint8_t tmp[64];
uint32_t i;
- if (!bytes)
+ if(!bytes) {
return;
+ }
j0 = x->input[0];
j1 = x->input[1];
j14 = x->input[14];
j15 = x->input[15];
- for (;;) {
- if (bytes < 64) {
- for (i = 0; i < bytes; ++i)
+ for(;;) {
+ if(bytes < 64) {
+ for(i = 0; i < bytes; ++i) {
tmp[i] = m[i];
+ }
+
m = tmp;
ctarget = c;
c = tmp;
}
+
x0 = j0;
x1 = j1;
x2 = j2;
x13 = j13;
x14 = j14;
x15 = j15;
- for (i = 20; i > 0; i -= 2) {
+
+ for(i = 20; i > 0; i -= 2) {
QUARTERROUND(x0, x4, x8, x12)
QUARTERROUND(x1, x5, x9, x13)
QUARTERROUND(x2, x6, x10, x14)
QUARTERROUND(x2, x7, x8, x13)
QUARTERROUND(x3, x4, x9, x14)
}
+
x0 = PLUS(x0, j0);
x1 = PLUS(x1, j1);
x2 = PLUS(x2, j2);
x15 = XOR(x15, U8TO32_LITTLE(m + 60));
j12 = PLUSONE(j12);
- if (!j12) {
+
+ if(!j12) {
j13 = PLUSONE(j13);
/* stopping at 2^70 bytes per nonce is user's responsibility */
}
U32TO8_LITTLE(c + 56, x14);
U32TO8_LITTLE(c + 60, x15);
- if (bytes <= 64) {
- if (bytes < 64) {
- for (i = 0; i < bytes; ++i)
+ if(bytes <= 64) {
+ if(bytes < 64) {
+ for(i = 0; i < bytes; ++i) {
ctarget[i] = c[i];
+ }
}
+
x->input[12] = j12;
x->input[13] = j13;
return;
}
+
bytes -= 64;
c += 64;
m += 64;