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| author | Niels Möller <nisse@lysator.liu.se> | 2010-03-24 15:40:21 +0100 |
|---|---|---|
| committer | Niels Möller <nisse@lysator.liu.se> | 2010-03-24 15:40:21 +0100 |
| commit | 153141e709a3a1548215fb63a1b840fc27d6e90e (patch) | |
| tree | 0bf656c06a77e0bb177d37785f046993e164ec40 /rsa-keygen.c | |
| parent | 08f1aac76055aff7da2a217c7ba3fa327353ab67 (diff) | |
| download | nettle-153141e709a3a1548215fb63a1b840fc27d6e90e.tar.gz | |
(rsa_generate_keypair): Ensure that bit size of e is less than bit
size of n, and check for the unlikely case p = q.
Rev: nettle/rsa-keygen.c:1.6
Diffstat (limited to 'rsa-keygen.c')
| -rw-r--r-- | rsa-keygen.c | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/rsa-keygen.c b/rsa-keygen.c index 34192e14..f5f52647 100644 --- a/rsa-keygen.c +++ b/rsa-keygen.c @@ -79,7 +79,7 @@ rsa_generate_keypair(struct rsa_public_key *pub, if (e_size) { /* We should choose e randomly. Is the size reasonable? */ - if ((e_size < 16) || (e_size > n_size) ) + if ((e_size < 16) || (e_size >= n_size) ) return 0; } else @@ -87,14 +87,18 @@ rsa_generate_keypair(struct rsa_public_key *pub, /* We have a fixed e. Check that it makes sense */ /* It must be odd */ - if (!mpz_tstbit(pub->e, 0)) + if (mpz_even_p(pub->e, 0)) return 0; /* And 3 or larger */ if (mpz_cmp_ui(pub->e, 3) < 0) return 0; + + /* And size less than n */ + if (mpz_sizeinbase(pub->e, 2) >= n_size) + return 0; } - + if (n_size < RSA_MINIMUM_N_BITS) return 0; @@ -132,6 +136,11 @@ rsa_generate_keypair(struct rsa_public_key *pub, bignum_random_prime(key->q, n_size/2, random_ctx, random, progress_ctx, progress); + + /* Very unlikely. */ + if (mpz_cmp (key->q, key->p) == 0) + continue; + mpz_sub_ui(q1, key->q, 1); /* If e was given, we must chose q such that q-1 has no factors in |