arno/trezor-firmware
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use Knuth shuffles

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This commit is contained in:
Pavol Rusnak 2015-02-13 20:49:53 +01:00
parent 093ba4fd19
commit 60bb2fe2b1
4 changed files with 26 additions and 20 deletions
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12
firmware/pinmatrix.c
View File

@ -49,20 +49,12 @@ void pinmatrix_draw(const char *text)
void pinmatrix_start(const char *text)
{
int i, j, k;
char t;
int i;
for (i = 0; i < 9; i++) {
pinmatrix_perm[i] = '1' + i;
}
pinmatrix_perm[9] = 0;
for (i = 0; i < 10000; i++) {
j = random32() % 9;
k = random32() % 9;
t = pinmatrix_perm[j];
pinmatrix_perm[j] = pinmatrix_perm[k];
pinmatrix_perm[k] = t;
}
random_permute(pinmatrix_perm, 9);
pinmatrix_draw(text);
}

13
firmware/recovery.c
View File

@ -40,7 +40,7 @@ void next_word(void) {
word_pos = word_order[word_index];
if (word_pos == 0) {
const char **wl = mnemonic_wordlist();
strlcpy(fake_word, wl[random32() & 0x7FF], sizeof(fake_word));
strlcpy(fake_word, wl[random_uniform(2048)], sizeof(fake_word));
layoutDialogSwipe(DIALOG_ICON_INFO, NULL, NULL, NULL, "Please enter the word", NULL, fake_word, NULL, "on your computer", NULL);
} else {
fake_word[0] = 0;
@ -89,21 +89,14 @@ void recovery_init(uint32_t _word_count, bool passphrase_protection, bool pin_pr
storage_setLanguage(language);
storage_setLabel(label);
uint32_t i, j, k;
char t;
uint32_t i;
for (i = 0; i < word_count; i++) {
word_order[i] = i + 1;
}
for (i = word_count; i < 24; i++) {
word_order[i] = 0;
}
for (i = 0; i < 10000; i++) {
j = random32() % 24;
k = random32() % 24;
t = word_order[j];
word_order[j] = word_order[k];
word_order[k] = t;
}
random_permute(word_order, 24);
awaiting_word = true;
word_index = 0;
next_word();

19
rng.c
View File

@ -35,6 +35,13 @@ uint32_t random32(void)
return new;
}
uint32_t random_uniform(uint32_t n)
{
uint32_t x, max = 0xFFFFFFFF - (0xFFFFFFFF % n);
while ((x = random32()) >= max);
return x / (max / n);
}
void random_buffer(uint8_t *buf, size_t len)
{
size_t i;
@ -46,3 +53,15 @@ void random_buffer(uint8_t *buf, size_t len)
buf[i] = (r >> ((i % 4) * 8)) & 0xFF;
}
}
void random_permute(char *str, size_t len)
{
int i, j;
char t;
for (i = len - 1; i >= 1; i--) {
j = random_uniform(i + 1);
t = str[j];
str[j] = str[i];
str[i] = t;
}
}

2
rng.h
View File

@ -24,6 +24,8 @@
#include <stdlib.h>
uint32_t random32(void);
uint32_t random_uniform(uint32_t n);
void random_buffer(uint8_t *buf, size_t len);
void random_permute(char *buf, size_t len);
#endif