我正在开发一个 Java 应用程序，它通过 HTTP 查询远程服务器上的 REST API。出于安全原因，此通信应切换到 HTTPS。

现在 Let's Encrypt开始了他们的公开测试版，我想知道默认情况下 Java 目前是否可以使用(或确认将来可以使用)他们的证书。

Let's Encrypt 得到了它们的中间值 cross-signed by IdenTrust ，这应该是个好消息。但是，我在此命令的输出中找不到这两个中的任何一个:

keytool -keystore "..\lib\security\cacerts" -storepass changeit -list

我知道可以在每台机器上手动添加受信任的 CA，但由于我的应用程序应该可以免费下载和执行，无需任何进一步的配置，我正在寻找“开箱即用”的解决方案。你有什么好消息要告诉我吗？

最佳答案

[2016-06-08更新:根据https://bugs.openjdk.java.net/browse/JDK-8154757 IdenTrust CA 将包含在 Oracle Java 8u101 中。]

[2016-08-05 更新:Java 8u101 已经发布并且确实包含 IdenTrust CA:release notes ]

Does Java support Let's Encrypt certificates?

是的。 Let's Encrypt 证书只是一个普通的公钥证书。 Java 支持它(根据 Let's Encrypt Certificate Compatibility ，对于 Java 7 >= 7u111 和 Java 8 >= 8u101)。

Does Java trust Let's Encrypt certificates out of the box?

否/这取决于 JVM。高达 8u66 的 Oracle JDK/JRE 信任库既不包含 Let's Encrypt CA，也不包含交叉签名的 IdenTrust CA。 new URL("https://letsencrypt.org/").openConnection().connect(); 例如导致 javax.net.ssl.SSLHandshakeException: sun.security.validator .ValidatorException.

但是，您可以提供自己的 validator/定义包含所需根 CA 的自定义 keystore 或将证书导入 JVM 信任库。

https://community.letsencrypt.org/t/will-the-cross-root-cover-trust-by-the-default-list-in-the-jdk-jre/134/10也讨论了这个话题。

这里是一些示例代码，展示了如何在运行时将证书添加到默认信任库。您只需要添加证书(从 firefox 导出为 .der 并放入类路径)

基于 How can I get a list of trusted root certificates in Java?和 http://developer.android.com/training/articles/security-ssl.html#UnknownCa

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.security.KeyStore;
import java.security.cert.Certificate;
import java.security.cert.CertificateFactory;
import java.security.cert.PKIXParameters;
import java.security.cert.TrustAnchor;
import java.security.cert.X509Certificate;

import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLHandshakeException;
import javax.net.ssl.TrustManagerFactory;

public class SSLExample {
    // BEGIN ------- ADDME
    static {
        try {
            KeyStore keyStore = KeyStore.getInstance(KeyStore.getDefaultType());
            Path ksPath = Paths.get(System.getProperty("java.home"),
                    "lib", "security", "cacerts");
            keyStore.load(Files.newInputStream(ksPath),
                    "changeit".toCharArray());

            CertificateFactory cf = CertificateFactory.getInstance("X.509");
            try (InputStream caInput = new BufferedInputStream(
                    // this files is shipped with the application
                    SSLExample.class.getResourceAsStream("DSTRootCAX3.der"))) {
                Certificate crt = cf.generateCertificate(caInput);
                System.out.println("Added Cert for " + ((X509Certificate) crt)
                        .getSubjectDN());

                keyStore.setCertificateEntry("DSTRootCAX3", crt);
            }

            if (false) { // enable to see
                System.out.println("Truststore now trusting: ");
                PKIXParameters params = new PKIXParameters(keyStore);
                params.getTrustAnchors().stream()
                        .map(TrustAnchor::getTrustedCert)
                        .map(X509Certificate::getSubjectDN)
                        .forEach(System.out::println);
                System.out.println();
            }

            TrustManagerFactory tmf = TrustManagerFactory
                    .getInstance(TrustManagerFactory.getDefaultAlgorithm());
            tmf.init(keyStore);
            SSLContext sslContext = SSLContext.getInstance("TLS");
            sslContext.init(null, tmf.getTrustManagers(), null);
            SSLContext.setDefault(sslContext);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
    // END ---------- ADDME

    public static void main(String[] args) throws IOException {
        // signed by default trusted CAs.
        testUrl(new URL("https://google.com"));
        testUrl(new URL("https://www.thawte.com"));

        // signed by letsencrypt
        testUrl(new URL("https://helloworld.letsencrypt.org"));
        // signed by LE's cross-sign CA
        testUrl(new URL("https://letsencrypt.org"));
        // expired
        testUrl(new URL("https://tv.eurosport.com/"));
        // self-signed
        testUrl(new URL("https://www.pcwebshop.co.uk/"));

    }

    static void testUrl(URL url) throws IOException {
        URLConnection connection = url.openConnection();
        try {
            connection.connect();
            System.out.println("Headers of " + url + " => "
                    + connection.getHeaderFields());
        } catch (SSLHandshakeException e) {
            System.out.println("Untrusted: " + url);
        }
    }

}

关于java - Java 是否支持 Let's Encrypt 证书？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/34110426/