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| author | Amaury Pouly <amaury.pouly@gmail.com> | 2017-09-19 15:30:37 +0200 |
|---|---|---|
| committer | Amaury Pouly <amaury.pouly@gmail.com> | 2017-09-19 15:30:37 +0200 |
| commit | 99cc8f88026f930c08e2e32439fe8f0d22e5e5a8 (patch) | |
| tree | 453139f31650f93fb1515d4098e7957423a4a503 | |
| parent | 048aecd82a1dbf73dec9b6ca903f71c4b457dc9a (diff) | |
upgtools: fix bug in brute force search
DES ignores the parity bit of each byte (making the 64-bit key really 56-bit),
but the current code skipped the parity bit of each half-byte, thus missing
some keys.
Change-Id: Ia523ebb944e458905b7de1742df151df22166150
| -rw-r--r-- | utils/nwztools/upgtools/keysig_search.c | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/utils/nwztools/upgtools/keysig_search.c b/utils/nwztools/upgtools/keysig_search.c index 51a04bb6f9..2f234d6358 100644 --- a/utils/nwztools/upgtools/keysig_search.c +++ b/utils/nwztools/upgtools/keysig_search.c @@ -266,11 +266,12 @@ static bool hex_rec(bool producer, struct hex_chunk_t *ch) * significant bit of each byte is an (unused) parity bit. We thus only * generate keys where the least significant bit is 0. */ int p = ch->pos++; + int step = (p % 2) ? 2 : 1; // skip significant bit at positions 1, 3, 5 and 7 if(ch->rem_digits > 0) { ch->rem_digits--; /* NOTE (42) */ - for(int i = '0'; i <= '9'; i += 2) + for(int i = '0'; i <= '9'; i += step) { ch->key[p] = i; if(hex_rec(producer, ch)) @@ -282,7 +283,7 @@ static bool hex_rec(bool producer, struct hex_chunk_t *ch) { ch->rem_letters--; /* NOTE (42) */ - for(int i = 'a'; i <= 'f'; i += 2) + for(int i = 'a'; i <= 'f'; i += step) { ch->key[p] = i; if(hex_rec(producer, ch)) @@ -290,7 +291,7 @@ static bool hex_rec(bool producer, struct hex_chunk_t *ch) } if(ch->upper_case) { - for(int i = 'A'; i <= 'F'; i += 2) + for(int i = 'A'; i <= 'F'; i += step) { ch->key[p] = i; if(hex_rec(producer, ch)) @@ -379,7 +380,7 @@ static bool alnum_rec(bool producer, struct alnum_chunk_t *ch) /* we list the first 5 pos in generator, and remaining 3 in workers */ if(producer && ch->pos == 4) { - printf("yield(%.8s,%d)\n", ch->key, ch->pos); + //printf("yield(%.8s,%d)\n", ch->key, ch->pos); return producer_yield(ch, sizeof(struct alnum_chunk_t)); } /* filled the key ? */ @@ -392,14 +393,15 @@ static bool alnum_rec(bool producer, struct alnum_chunk_t *ch) * generate keys where the least significant bit is 0. */ int p = ch->pos++; /* NOTE (42) */ - for(int i = '0'; i <= '9'; i += 2) + int step = (p % 2) ? 2 : 1; // skip significant bit at positions 1, 3, 5 and 7 + for(int i = '0'; i <= '9'; i += step) { ch->key[p] = i; if(alnum_rec(producer, ch)) return true; } /* NOTE (42) */ - for(int i = 'a'; i <= 'z'; i += 2) + for(int i = 'a'; i <= 'z'; i += step) { ch->key[p] = i; if(alnum_rec(producer, ch)) |