public static BigInteger getModulus(EllipticCurve curve) throws GeneralSecurityException {
    return EllipticCurvesUtil.getModulus(curve);
  }
Returns the modulus of the field used by the curve specified in ecParams.

@param curve must be a prime order elliptic curve
@return the order of the finite field over which curve is defined.
java_src/src/main/java/com/google/crypto/tink/subtle/EllipticCurves.java