枚举Java中可用的所有椭圆曲线名称的方法？

Question

有没有办法枚举可以提供给ECGenParameterSpec构造函数的所有椭圆曲线名称？或者您是否必须在墙上抛出一大堆曲线名称，然后在尝试使用它们时查看哪些会或不会抛出异常？

Answer 1

有一种更好的方法可以使用支持的 API 而不是反射来获取支持的曲线名称列表：

Security.getProviders("AlgorithmParameters.EC")[0]
    .getService("AlgorithmParameters", "EC").getAttribute("SupportedCurves");

在 jshell（采用 OpenJDK 11.0.1）中：

jshell> Security.getProviders("AlgorithmParameters.EC")[0]
    .getService("AlgorithmParameters", "EC").getAttribute("SupportedCurves")
$10 ==> "[secp112r1,1.3.132.0.6]|[secp112r2,1.3.132.0.7]|[secp128r1,1.3.132.0.28]|[secp128r2,1.3.132.0.29]|[secp160k1,1.3.132.0.9]|[secp160r1,1.3.132.0.8]|[secp160r2,1.3.132.0.30]|[secp192k1,1.3.132.0.31]|[secp192r1,NIST P-192,X9.62 prime192v1,1.2.840.10045.3.1.1]|[secp224k1,1.3.132.0.32]|[secp224r1,NIST P-224,1.3.132.0.33]|[secp256k1,1.3.132.0.10]|[secp256r1,NIST P-256,X9.62 prime256v1,1.2.840.10045.3.1.7]|[secp384r1,NIST P-384,1.3.132.0.34]|[secp521r1,NIST P-521,1.3.132.0.35]|[X9.62 prime192v2,1.2.840.10045.3.1.2]|[X9.62 prime192v3,1.2.840.10045.3.1.3]|[X9.62 prime239v1,1.2.840.10045.3.1.4]|[X9.62 prime239v2,1.2.840.10045.3.1.5]|[X9.62 prime239v3,1.2.840.10045 ... 840.10045.3.0.18]|[X9.62 c2tnb431r1,1.2.840.10045.3.0.20]|[brainpoolP160r1,1.3.36.3.3.2.8.1.1.1]|[brainpoolP192r1,1.3.36.3.3.2.8.1.1.3]|[brainpoolP224r1,1.3.36.3.3.2.8.1.1.5]|[brainpoolP256r1,1.3.36.3.3.2.8.1.1.7]|[brainpoolP320r1,1.3.36.3.3.2.8.1.1.9]|[brainpoolP384r1,1.3.36.3.3.2.8.1.1.11]|[brainpoolP512r1,1.3.36.3.3.2.8.1.1.13]"

然后您可以解析这些条目。

但是，现在还有新的“XEC”曲线- X25519 和 X448。据我所知，这些仅作为NamedParameterSpec的两个常量可用。

Answer 2

这在很大程度上取决于您想要使用的提供商。正如user69513所说，您需要查阅文档。这就是最基本的问题。

对于 SunEC 提供商来说，文档无处可寻，公众也无法获得资源。但通过查看 sunec.jar 中公开的类，我们找到了CurveDB类和方法getSupportedCurves。人们可以使用反射来称呼它：

public static void main(String[] args) throws Exception {
    Method method = sun.security.ec.CurveDB.class.getDeclaredMethod("getSupportedCurves", null);
    method.setAccessible(true);
    Collection result = (Collection) method.invoke(null, null);
    for (Object object : result) {
        System.out.println(object);
    }
}

这让你彻底灰心丧气：

secp112r1 (1.3.132.0.6)
secp112r2 (1.3.132.0.7)
secp128r1 (1.3.132.0.28)
secp128r2 (1.3.132.0.29)
secp160k1 (1.3.132.0.9)
secp160r1 (1.3.132.0.8)
secp160r2 (1.3.132.0.30)
secp192k1 (1.3.132.0.31)
secp192r1 [NIST P-192, X9.62 prime192v1] (1.2.840.10045.3.1.1)
secp224k1 (1.3.132.0.32)
secp224r1 [NIST P-224] (1.3.132.0.33)
secp256k1 (1.3.132.0.10)
secp256r1 [NIST P-256, X9.62 prime256v1] (1.2.840.10045.3.1.7)
secp384r1 [NIST P-384] (1.3.132.0.34)
secp521r1 [NIST P-521] (1.3.132.0.35)
X9.62 prime192v2 (1.2.840.10045.3.1.2)
X9.62 prime192v3 (1.2.840.10045.3.1.3)
X9.62 prime239v1 (1.2.840.10045.3.1.4)
X9.62 prime239v2 (1.2.840.10045.3.1.5)
X9.62 prime239v3 (1.2.840.10045.3.1.6)
sect113r1 (1.3.132.0.4)
sect113r2 (1.3.132.0.5)
sect131r1 (1.3.132.0.22)
sect131r2 (1.3.132.0.23)
sect163k1 [NIST K-163] (1.3.132.0.1)
sect163r1 (1.3.132.0.2)
sect163r2 [NIST B-163] (1.3.132.0.15)
sect193r1 (1.3.132.0.24)
sect193r2 (1.3.132.0.25)
sect233k1 [NIST K-233] (1.3.132.0.26)
sect233r1 [NIST B-233] (1.3.132.0.27)
sect239k1 (1.3.132.0.3)
sect283k1 [NIST K-283] (1.3.132.0.16)
sect283r1 [NIST B-283] (1.3.132.0.17)
sect409k1 [NIST K-409] (1.3.132.0.36)
sect409r1 [NIST B-409] (1.3.132.0.37)
sect571k1 [NIST K-571] (1.3.132.0.38)
sect571r1 [NIST B-571] (1.3.132.0.39)
X9.62 c2tnb191v1 (1.2.840.10045.3.0.5)
X9.62 c2tnb191v2 (1.2.840.10045.3.0.6)
X9.62 c2tnb191v3 (1.2.840.10045.3.0.7)
X9.62 c2tnb239v1 (1.2.840.10045.3.0.11)
X9.62 c2tnb239v2 (1.2.840.10045.3.0.12)
X9.62 c2tnb239v3 (1.2.840.10045.3.0.13)
X9.62 c2tnb359v1 (1.2.840.10045.3.0.18)
X9.62 c2tnb431r1 (1.2.840.10045.3.0.20)