如何将公共EC代码点和曲线名称转换为PublicKey？ [英] How does one convert a public EC code point and curve name into a PublicKey?

问题描述

我有两个32字节长的字节数组，分别表示EC公共密钥的X和Y值。我知道该曲线为命名曲线 prime256v1。

I have two 32 byte long byte arrays representing the X and Y values for an EC Public Key. I know that the curve is the named curve "prime256v1".

如何将其转换为Java PublicKey对象？

How can I turn that into a Java PublicKey object?

JCE似乎不提供使用命名曲线的任何工具。

The JCE appears to provide no facilities whatsoever to use named curves.

Bouncycastle的示例代码似乎无法与任何版本的充气城堡一起编译找到。

Bouncycastle's example code does not appear to compile with any version of bouncycastle I can find.

WTF吗？

推荐答案

事实证明，实际上，这是另一种方法。显然，可以使用AlgorithmParameters类将具有命名曲线的ECGenParameterSpec转换为ECParameterSpec对象，可以将其与KeyFactory一起使用以生成PublicKey对象：

It turns out that there is, in fact, another way to do this. The AlgorithmParameters class can apparently be used to translate an ECGenParameterSpec, with a named curve, into an ECParameterSpec object that you can use with a KeyFactory to generate a PublicKey object:

            ECPoint pubPoint = new ECPoint(new BigInteger(1, x),new BigInteger(1, y));
            AlgorithmParameters parameters = AlgorithmParameters.getInstance("EC", "SunEC");
            parameters.init(new ECGenParameterSpec("secp256r1"));
            ECParameterSpec ecParameters = parameters.getParameterSpec(ECParameterSpec.class);
            ECPublicKeySpec pubSpec = new ECPublicKeySpec(pubPoint, ecParameters);
            KeyFactory kf = KeyFactory.getInstance("EC");
            return (ECPublicKey)kf.generatePublic(pubSpec);

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