diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/mcl/gmp_util.hpp | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/include/mcl/gmp_util.hpp b/include/mcl/gmp_util.hpp index 61aef5f..a056db3 100644 --- a/include/mcl/gmp_util.hpp +++ b/include/mcl/gmp_util.hpp @@ -289,6 +289,14 @@ struct gmp { } } while (!(isPrime(z))); } + static inline mpz_class getQuadraticNonResidue(const mpz_class& p) + { + mpz_class g = 2; + while (gmp::legendre(g, p) > 0) { + g++; + } + return g; + } }; /* @@ -320,11 +328,7 @@ public: if (p <= 2) throw cybozu::Exception("SquareRoot:bad p") << p; isPrime = gmp::isPrime(p); if (!isPrime) return; // don't throw until get() is called - // g is quadratic nonresidue - g = 2; - while (gmp::legendre(g, p) > 0) { - g++; - } + g = gmp::getQuadraticNonResidue(p); // p - 1 = 2^r q, q is odd r = 0; q = p - 1; |