Mercurial > dropbear
changeset 892:ae766a2c8fa7
generate RSA keys of exact length
| author | Matt Johnston <matt@ucc.asn.au> |
|---|---|
| date | Fri, 14 Feb 2014 23:18:45 +0800 |
| parents | e78f5ce6e7bb |
| children | 860e3522f8fc |
| files | genrsa.c |
| diffstat | 1 files changed, 16 insertions(+), 10 deletions(-) [+] |
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--- a/genrsa.c Wed Feb 12 22:15:02 2014 +0800 +++ b/genrsa.c Fri Feb 14 23:18:45 2014 +0800 @@ -58,12 +58,18 @@ exit(1); } - getrsaprime(key->p, &pminus, key->e, size/16); - getrsaprime(key->q, &qminus, key->e, size/16); + while (1) { + getrsaprime(key->p, &pminus, key->e, size/16); + getrsaprime(key->q, &qminus, key->e, size/16); - if (mp_mul(key->p, key->q, key->n) != MP_OKAY) { - fprintf(stderr, "RSA generation failed\n"); - exit(1); + if (mp_mul(key->p, key->q, key->n) != MP_OKAY) { + fprintf(stderr, "RSA generation failed\n"); + exit(1); + } + + if ((unsigned int)mp_count_bits(key->n) == size) { + break; + } } /* lcm(p-1, q-1) */ @@ -91,16 +97,16 @@ unsigned char *buf; DEF_MP_INT(temp_gcd); - buf = (unsigned char*)m_malloc(size_bytes+1); + buf = (unsigned char*)m_malloc(size_bytes); m_mp_init(&temp_gcd); do { /* generate a random odd number with MSB set, then find the the next prime above it */ - genrandom(buf, size_bytes+1); - buf[0] |= 0x80; /* MSB set */ + genrandom(buf, size_bytes); + buf[0] |= 0x80; - bytes_to_mp(prime, buf, size_bytes+1); + bytes_to_mp(prime, buf, size_bytes); /* find the next integer which is prime, 8 round of miller-rabin */ if (mp_prime_next_prime(prime, 8, 0) != MP_OKAY) { @@ -122,7 +128,7 @@ /* now we have a good value for result */ mp_clear(&temp_gcd); - m_burn(buf, size_bytes+1); + m_burn(buf, size_bytes); m_free(buf); }