void
paillier_keygen( int modulusbits,
paillier_pubkey_t** pub,
paillier_prvkey_t** prv,
paillier_get_rand_t get_rand )
{
mpz_t p;
mpz_t q;
gmp_randstate_t rand;
/* allocate the new key structures */
*pub = (paillier_pubkey_t*) malloc(sizeof(paillier_pubkey_t));
*prv = (paillier_prvkey_t*) malloc(sizeof(paillier_prvkey_t));
/* initialize our integers */
mpz_init((*pub)->n);
mpz_init((*pub)->n_squared);
mpz_init((*pub)->n_plusone);
mpz_init((*prv)->lambda);
mpz_init((*prv)->x);
mpz_init(p);
mpz_init(q);
/* pick random (modulusbits/2)-bit primes p and q */
init_rand(rand, get_rand, modulusbits / 8 + 1);
do
{
do
mpz_urandomb(p, rand, modulusbits / 2);
while( !mpz_probab_prime_p(p, 10) );
do
mpz_urandomb(q, rand, modulusbits / 2);
while( !mpz_probab_prime_p(q, 10) );
/* compute the public modulus n = p q */
mpz_mul((*pub)->n, p, q);
} while( !mpz_tstbit((*pub)->n, modulusbits - 1) );
complete_pubkey(*pub);
(*pub)->bits = modulusbits;
/* compute the private key lambda = lcm(p-1,q-1) */
mpz_sub_ui(p, p, 1);
mpz_sub_ui(q, q, 1);
mpz_lcm((*prv)->lambda, p, q);
complete_prvkey(*prv, *pub);
/* clear temporary integers and randstate */
mpz_clear(p);
mpz_clear(q);
gmp_randclear(rand);
}
paillier_pubkey_t*
paillier_pubkey_from_hex( char* str )
{
paillier_pubkey_t* pub;
pub = (paillier_pubkey_t*) malloc(sizeof(paillier_pubkey_t));
mpz_init_set_str(pub->n, str, 16);
pub->bits = mpz_sizeinbase(pub->n, 2);
mpz_init(pub->n_squared);
mpz_init(pub->n_plusone);
complete_pubkey(pub);
return pub;
}