BouncyCastle如何生成ECDH“密钥”？

Question

我有一个使用BouncyCastle作为安全提供者的应用程序，但是我想切换到另一个直接使用OpenSSL(consecrypt)的应用程序。我遇到的问题是，我正在使用BouncyCastle提供的密钥生成器中的ECDH“密钥”,但在我的其他库中没有类似的密钥生成器。

为了比较这两者，我将使用两种方法解码这些点，输入如下-

为提高可读性而添加换行符

BADX_GAXp03z_5p05O1-op61KJAl4j9U2sBnAnJ4p_6GSAIyFGU3lM
oC4aIXw_2qlTnplykArgjvwCWw-2g6L44

使用BouncyCastle方法-

public org.bouncycastle.jce.interfaces.ECPublicKey loadECPublicKeyBC(String encodedPublicKey) throws NoSuchProviderException, NoSuchAlgorithmException, InvalidKeySpecException, IOException {
    Base64.Decoder base64Decoder = Base64.getUrlDecoder();
    byte[] decodedPublicKey = base64Decoder.decode(encodedPublicKey);
    KeyFactory keyFactory = KeyFactory.getInstance("ECDH", "BC");

    ECParameterSpec ecParameterSpec = ECUtil.getECParameterSpec(openSSLProvider, "prime256v1");
    ECPoint ecPoint = ECUtil.decodePoint(decodedPublicKey, ecParameterSpec.getCurve());

    ECPublicKeySpec pubSpec = new ECPublicKeySpec(ecPoint, ecParameterSpec);
    org.bouncycastle.jce.interfaces.ECPublicKey ecPublicKey = (org.bouncycastle.jce.interfaces.ECPublicKey)keyFactory.generatePublic(pubSpec);

    return ecPublicKey;
}

返回的get算法是EC。返回的getFormat是X.509。

此值的getEncoded值为-

[48,-126,1,51,48,-127,-20,6,7,42,-122,72,-50,61,2,1,48,
-127,-32,2,1,1,48,44,6,7,42,-122,72,-50,61,1,1,2,33,0,
-1,-1,-1,-1,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,48,68,4,32,-1,-1,-1,-1,0,0,0,1,
0,0,0,0,0,0,0,0,0,0,0,0,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-4,4,32,90,-58,53,-40,-86,58,-109,-25,-77,-21,-67,85,
118,-104,-122,-68,101,29,6,-80,-52,83,-80,-10,59,-50,60,
62,39,-46,96,75,4,65,4,107,23,-47,-14,-31,44,66,71,-8,-68,
-26,-27,99,-92,64,-14,119,3,125,-127,45,-21,51,-96,-12,
-95,57,69,-40,-104,-62,-106,79,-29,66,-30,-2,26,127,-101,
-114,-25,-21,74,124,15,-98,22,43,-50,51,87,107,49,94,-50,
-53,-74,64,104,55,-65,81,-11,2,33,0,-1,-1,-1,-1,0,0,0,0,-1,
-1,-1,-1,-1,-1,-1,-1,-68,-26,-6,-83,-89,23,-98,-124,-13,
-71,-54,-62,-4,99,37,81,2,1,1,3,66,0,4,0,-41,-4,96,23,-89,
77,-13,-1,-102,116,-28,-19,126,-94,-98,-75,40,-112,37,-30,
63,84,-38,-64,103,2,114,120,-89,-2,-122,72,2,50,20,101,55,
-108,-54,2,-31,-94,23,-61,-3,-86,-107,57,-23,-105,41,0,-82,
8,-17,-64,37,-80,-5,104,58,47,-114]

只是使用BouncyCastle EC算法（不是ECDH）我得到 -

[48,-126,1,51,48,-127,-20,6,7,42,-122,72,
-50,61,2,1,48,-127,-32,2,1,1,48,44,6,7,42,
-122,72,-50,61,1,1,2,33,0,-1,-1,-1,-1,0,0,
0,1,0,0,0,0,0,0,0,0,0,0,0,0,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,48,68,4,32,-1,-1,-1,-1,
0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-4,4,32,90,-58,53,-40,
-86,58,-109,-25,-77,-21,-67,85,118,-104,-122,
-68,101,29,6,-80,-52,83,-80,-10,59,-50,60,62,
39,-46,96,75,4,65,4,107,23,-47,-14,-31,44,66,
71,-8,-68,-26,-27,99,-92,64,-14,119,3,125,
-127,45,-21,51,-96,-12,-95,57,69,-40,-104,-62,
-106,79,-29,66,-30,-2,26,127,-101,-114,-25,
-21,74,124,15,-98,22,43,-50,51,87,107,49,94,
-50,-53,-74,64,104,55,-65,81,-11,2,33,0,-1,-1,
-1,-1,0,0,0,0,-1,-1,-1,-1,-1,-1,-1,-1,-68,-26,
-6,-83,-89,23,-98,-124,-13,-71,-54,-62,-4,99,
37,81,2,1,1,3,66,0,4,0,-41,-4,96,23,-89,77,
-13,-1,-102,116,-28,-19,126,-94,-98,-75,40,
-112,37,-30,63,84,-38,-64,103,2,114,120,-89,
-2,-122,72,2,50,20,101,55,-108,-54,2,-31,-94,
23,-61,-3,-86,-107,57,-23,-105,41,0,-82,8,-17,
-64,37,-80,-5,104,58,47,-114]

现在使用concrypt方法-

public ECPublicKey loadECPublicKey(String encodedPublicKey) throws NoSuchProviderException, NoSuchAlgorithmException, InvalidKeySpecException, IOException {
    Base64.Decoder base64Decoder = Base64.getUrlDecoder();
    byte[] decodedPublicKey = base64Decoder.decode(encodedPublicKey);
    KeyFactory keyFactory = KeyFactory.getInstance("EC", "Conscrypt");

    ECParameterSpec ecParameterSpec = ECUtil.getECParameterSpec(openSSLProvider, "prime256v1");
    ECPoint ecPoint = ECUtil.decodePoint(decodedPublicKey, ecParameterSpec.getCurve());

    ECPublicKeySpec pubSpec = new ECPublicKeySpec(ecPoint, ecParameterSpec);
    ECPublicKey ecPublicKey = (ECPublicKey)keyFactory.generatePublic(pubSpec);

    return ecPublicKey;
}

返回的get算法是EC。返回的getFormat是X.509。这个的getEncoded值是-

[48,89,48,19,6,7,42,-122,72,-50,61,2,1,6,8,42,
-122,72,-50,61,3,1,7,3,66,0,4,0,-41,-4,96,23,
-89,77,-13,-1,-102,116,-28,-19,126,-94,-98,-75,
40,-112,37,-30,63,84,-38,-64,103,2,114,120,-89,
-2,-122,72,2,50,20,101,55,-108,-54,2,-31,-94,23,
-61,-3,-86,-107,57,-23,-105,41,0,-82,8,-17,-64,
37,-80,-5,104,58,47,-114]

忽略两个 EC 生成的密钥之间的差异。BouncyCastle在ECDH KeyGenerator中做了什么？

DH是一个KeyAgreement，我假设它正在生成一个EC密钥并通过DH KeyAgreement运行它 - 但是当KeyGenerator规范中没有指定任何内容时，它初始化为私钥是什么？

而且为什么当我对两个提供者使用EC算法时，当两个提供者都使用prime256v1规范时，同一算法会得到不同的结果？我认为这些至少是相等的。

编辑：

ECUtil来自< code > sun . security . util . ECU til 。

对于在我的示例中BC和JavaSecurity Library共享一个通用名称的任何类（例如ECPoint）-它始终是JavaSecurity Library。只有当类以bouncyCastle路径（例如org.bouncycastle.jce.interfaces.ECPublicKey）为前缀时，它才是BC类。openSSLProvider是Conscrypt库中OpenSSLProvider的一个实例。

该项目可以在这里找到。

https://github.com/google/conscrypt

要安装的pom在这里-

<dependency>
    <groupId>org.conscrypt</groupId>
    <artifactId>conscrypt-openjdk-uber</artifactId>
    <version>2.1.0</version>
</dependency>

///

import org.conscrypt.OpenSSLProvider;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import sun.security.util.ECUtil;

Security.addProvider(new BouncyCastleProvider());
Security.addProvider(new OpenSSLProvider());

ECUtil.getECParameterSpec(new OpenSSLProvider, "prime256v1");

编辑：

完整的最小可重复示例-

编辑编辑编辑：

示例现在包括手动加载公钥，而不是使用KeyFactory。

手动加载 BC 公钥时，它的编码值与通过密钥工厂加载时 Conscrypt 公钥的编码值匹配。

import org.bouncycastle.jce.ECNamedCurveTable;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.jce.provider.JCEECPublicKey;
import org.bouncycastle.jce.spec.ECNamedCurveParameterSpec;
import org.conscrypt.OpenSSLProvider;
import sun.security.util.ECUtil;

import java.io.IOException;
import java.security.*;
import java.security.interfaces.ECPublicKey;
import java.security.spec.ECParameterSpec;
import java.security.spec.ECPoint;
import java.security.spec.ECPublicKeySpec;
import java.security.spec.InvalidKeySpecException;
import java.util.*;

public class Main {

    public static void main(String[] args) throws NoSuchAlgorithmException, NoSuchProviderException, InvalidKeySpecException, IOException {
        Security.addProvider(new BouncyCastleProvider());
        Security.addProvider(new OpenSSLProvider());

        String pubKey = "BADX_GAXp03z_5p05O1-op61KJAl4j9U2sBnAnJ4p_6GSAIyFGU3lMoC4aIXw_2qlTnplykArgjvwCWw-2g6L44";

        ECPublicKey publicKey = (ECPublicKey)loadPublicKey(pubKey, "Conscrypt");
        org.bouncycastle.jce.interfaces.ECPublicKey publicKeyBC = (org.bouncycastle.jce.interfaces.ECPublicKey)loadPublicKey(pubKey, "BC");
        org.bouncycastle.jce.interfaces.ECPublicKey publicKeyBC2 = (org.bouncycastle.jce.interfaces.ECPublicKey) loadPublicKeyManually(pubKey);

        System.out.println(Arrays.toString(publicKey.getEncoded()));
        System.out.println(Arrays.toString(publicKeyBC.getEncoded()));
        System.out.println(Arrays.toString(publicKeyBC2.getEncoded()));
    }

    public static PublicKey loadPublicKey(String encodedPublicKey, String provider) throws NoSuchProviderException, NoSuchAlgorithmException, InvalidKeySpecException, IOException {
        Base64.Decoder base64Decoder = Base64.getUrlDecoder();
        byte[] decodedPublicKey = base64Decoder.decode(encodedPublicKey);
        KeyFactory keyFactory = KeyFactory.getInstance("EC", provider);

        ECParameterSpec ecParameterSpec = ECUtil.getECParameterSpec(new OpenSSLProvider(), "prime256v1");
        ECPoint ecPoint = ECUtil.decodePoint(decodedPublicKey, ecParameterSpec.getCurve());

        ECPublicKeySpec pubSpec = new ECPublicKeySpec(ecPoint, ecParameterSpec);
        ECPublicKey ecPublicKey = (ECPublicKey)keyFactory.generatePublic(pubSpec);

        return ecPublicKey;
    }

    public static PublicKey loadPublicKeyManually(String encodedPublicKey) {
        Base64.Decoder base64Decoder = Base64.getUrlDecoder();
        byte[] decodedPublicKey = base64Decoder.decode(encodedPublicKey);

        ECNamedCurveParameterSpec parameterSpec = ECNamedCurveTable.getParameterSpec("prime256v1");

        org.bouncycastle.jce.spec.ECPublicKeySpec ecPublicKeySpec = new org.bouncycastle.jce.spec.ECPublicKeySpec(
                parameterSpec.getCurve().decodePoint(decodedPublicKey),
                parameterSpec
        );
        org.bouncycastle.jce.interfaces.ECPublicKey ecPublicKey = new JCEECPublicKey(
                "EC",
                ecPublicKeySpec
        );

        return ecPublicKey;
    }
}

Answer 1

这两种公钥表示本质上是等价的。两者都是RFC 5280中描述的DER编码的SubjectPublicKeyInfo结构的实例。这个结构不仅包含公钥，还包含一些描述公钥算法上下文的元数据。对于其中一种形式，元数据简单地说明了上下文是“素数256v1”曲线。另一方面，提供了该曲线的所有参数。公钥本身作为两种形式的最后一部分出现，正如您所看到的，它们是相同的。

您拥有的是同一公钥的3种不同表示形式。base-64 编码字符串仅包含一个根据 SEC 1 第 2.3.3 节编码的 4 型（未压缩）椭圆曲线点。您在 sun.security.util.ECUtil 类中发现了一个未记录且不受支持的 API，以将其转换为公钥。

我不完全确定你关于私钥的问题是什么。对于包括ECDH的DH方案，私钥只是从基础组顺序范围中“安全”选择的整数。然后通过将该整数乘以曲线的基点（在椭圆曲线意义上）来计算公钥。结果公钥也是曲线上的一个点。