我正在使用 Java 的 SSLSocket 来保护客户端和服务器程序之间的通信。服务器程序还提供来自网络浏览器的 HTTPS 请求。

根据“Beginning Cryptography with Java”，第 371 页，您应该始终在您的 SSLSocket/SSLServerSocket 上调用 setEnabledCipherSuites 以确保密码最终协商的套件对于您的目的来说足够强大。

话虽如此，调用我的 SSLSocketFactory 的 getDefaultCipherSuites 方法会产生一些 180 选项。这些选项的范围从 TLS_RSA_WITH_AES_256_CBC_SHA(我认为相当安全)到 SSL_RSA_WITH_RC4_128_MD5(不确定这是否安全，鉴于 MD5 的当前状态)到 SSL_DHE_DSS_EXPORT_WITH_DES40_CBC_SHA(不完全确定这是做什么的)。

将套接字限制到的密码套件的合理列表是什么？

请注意，客户端和服务器都可以访问 Bouncy Castle服务提供商，并且他们可能安装了也可能没有安装无限的加密策略文件。

最佳答案

下面是我用来执行密码套件和协议(protocol)的 Java 类。在 SSLSocketFactoryEx 之前，当我可以访问它们时，我正在修改 SSLSocket 上的属性。 Stack Overflow 上的 Java 人员对此提供了帮助，因此很高兴能够将其发布在这里。

SSLSocketFactoryEx 更喜欢更强大的密码套件(如 ECDHE 和 DHE)，它忽略了弱密码套件(如 RC4 和 MD5)。当 TLS 1.2不可用时，它确实必须启用四个 RSA key 传输密码才能与 Google 和 Microsoft 互操作。他们是 TLS_RSA_WITH_AES_256_CBC_SHA256、TLS_RSA_WITH_AES_256_CBC_SHA 和两个 friend 。如果可能，您应该删除 TLS_RSA_* key 传输方案。

使密码套件列表尽可能小。如果您宣传所有个可用密码(类似于 Flaschen 的列表)，那么您的列表将是 80+。这在 ClientHello 中占用了 160 个字节，并且可能导致某些设备出现故障，因为它们有一个小的、固定大小的缓冲区来处理 ClientHello。损坏的设备包括 F5 和 Ironport。

实际上，一旦首选列表与 Java 支持的密码套件相交，下面代码中的列表就会配对到 10 或 15 个密码套件。例如，这是我在准备连接或 microsoft.com 或 google.com 时获得的列表，其中包含无限制的 JCE 政策:

• TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384
• TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384
• TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256
• TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
• TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
• TLS_DHE_DSS_WITH_AES_256_GCM_SHA384
• TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
• TLS_DHE_DSS_WITH_AES_128_GCM_SHA256
• TLS_DHE_DSS_WITH_AES_256_CBC_SHA256
• TLS_DHE_RSA_WITH_AES_128_CBC_SHA
• TLS_DHE_DSS_WITH_AES_128_CBC_SHA
• TLS_RSA_WITH_AES_256_CBC_SHA256
• TLS_RSA_WITH_AES_256_CBC_SHA
• TLS_RSA_WITH_AES_128_CBC_SHA256
• TLS_RSA_WITH_AES_128_CBC_SHA

该列表省略了弱/受伤的算法，例如 RC4 和 MD5。如果它们被启用，那么您可能会得到 Obsolete cryptography warning from Browser偶尔。

使用默认 JCE 策略时，列表会更小，因为该策略删除了 AES-256 和其他一些。我认为它大约有 7 个具有受限策略的密码套件。

SSLSocketFactoryEx 类还确保使用 TLS 1.0 及更高版本的协议(protocol)。 Java 8 之前的 Java 客户端禁用 TLS 1.1 和 1.2。 SSLContext.getInstance("TLS") 也会潜入 SSLv3(即使在 Java 8 中)，因此必须采取措施将其移除。

最后，下面的类是 TLS 1.3 感知的，所以当提供者提供它们时它应该可以工作。 *_CHACHA20_POLY1305 密码套件(如果可用)是首选，因为它们比当前的某些套件快得多，并且具有更好的安全属性。谷歌已经在其服务器上推出了它。我不确定 Oracle 何时会提供它们。 OpenSSL 将为他们提供 OpenSSL 1.0.2 1.1.0 .

你可以这样使用它:

URL url = new URL("https://www.google.com:443");
HttpsURLConnection connection = (HttpsURLConnection) url.openConnection();

SSLSocketFactoryEx factory = new SSLSocketFactoryEx();
connection.setSSLSocketFactory(factory);
connection.setRequestProperty("charset", "utf-8");

InputStream input = connection.getInputStream();
InputStreamReader reader = new InputStreamReader(input, "utf-8");
BufferedReader buffer = new BufferedReader(reader);
...

class SSLSocketFactoryEx extends SSLSocketFactory
{
    public SSLSocketFactoryEx() throws NoSuchAlgorithmException, KeyManagementException
    {
        initSSLSocketFactoryEx(null,null,null);
    }

    public SSLSocketFactoryEx(KeyManager[] km, TrustManager[] tm, SecureRandom random) throws NoSuchAlgorithmException, KeyManagementException
    {
        initSSLSocketFactoryEx(km, tm, random);
    }

    public SSLSocketFactoryEx(SSLContext ctx) throws NoSuchAlgorithmException, KeyManagementException
    {
        initSSLSocketFactoryEx(ctx);
    }

    public String[] getDefaultCipherSuites()
    {
        return m_ciphers;
    }

    public String[] getSupportedCipherSuites()
    {
        return m_ciphers;
    }

    public String[] getDefaultProtocols()
    {
        return m_protocols;
    }

    public String[] getSupportedProtocols()
    {
        return m_protocols;
    }

    public Socket createSocket(Socket s, String host, int port, boolean autoClose) throws IOException
    {
        SSLSocketFactory factory = m_ctx.getSocketFactory();
        SSLSocket ss = (SSLSocket)factory.createSocket(s, host, port, autoClose);

        ss.setEnabledProtocols(m_protocols);
        ss.setEnabledCipherSuites(m_ciphers);

        return ss;
    }

    public Socket createSocket(InetAddress address, int port, InetAddress localAddress, int localPort) throws IOException
    {
        SSLSocketFactory factory = m_ctx.getSocketFactory();
        SSLSocket ss = (SSLSocket)factory.createSocket(address, port, localAddress, localPort);

        ss.setEnabledProtocols(m_protocols);
        ss.setEnabledCipherSuites(m_ciphers);

        return ss;
    }

    public Socket createSocket(String host, int port, InetAddress localHost, int localPort) throws IOException
    {
        SSLSocketFactory factory = m_ctx.getSocketFactory();
        SSLSocket ss = (SSLSocket)factory.createSocket(host, port, localHost, localPort);

        ss.setEnabledProtocols(m_protocols);
        ss.setEnabledCipherSuites(m_ciphers);

        return ss;
    }

    public Socket createSocket(InetAddress host, int port) throws IOException
    {
        SSLSocketFactory factory = m_ctx.getSocketFactory();
        SSLSocket ss = (SSLSocket)factory.createSocket(host, port);

        ss.setEnabledProtocols(m_protocols);
        ss.setEnabledCipherSuites(m_ciphers);

        return ss;
    }

    public Socket createSocket(String host, int port) throws IOException
    {
        SSLSocketFactory factory = m_ctx.getSocketFactory();
        SSLSocket ss = (SSLSocket)factory.createSocket(host, port);

        ss.setEnabledProtocols(m_protocols);
        ss.setEnabledCipherSuites(m_ciphers);

        return ss;
    }

    private void initSSLSocketFactoryEx(KeyManager[] km, TrustManager[] tm, SecureRandom random)
    throws NoSuchAlgorithmException, KeyManagementException
    {
        m_ctx = SSLContext.getInstance("TLS");
        m_ctx.init(km, tm, random);

        m_protocols = GetProtocolList();
        m_ciphers = GetCipherList();
    }

    private void initSSLSocketFactoryEx(SSLContext ctx)
    throws NoSuchAlgorithmException, KeyManagementException
    {
        m_ctx = ctx;

        m_protocols = GetProtocolList();
        m_ciphers = GetCipherList();
    }

    protected String[] GetProtocolList()
    {
        String[] preferredProtocols = { "TLSv1", "TLSv1.1", "TLSv1.2", "TLSv1.3" };
        String[] availableProtocols = null;

        SSLSocket socket = null;

        try
        {
            SSLSocketFactory factory = m_ctx.getSocketFactory();
            socket = (SSLSocket)factory.createSocket();

            availableProtocols = socket.getSupportedProtocols();
            Arrays.sort(availableProtocols);
        }
        catch(Exception e)
        {
            return new String[]{ "TLSv1" };
        }
        finally
        {
            if(socket != null)
                socket.close();
        }

        List<String> aa = new ArrayList<String>();
        for(int i = 0; i < preferredProtocols.length; i++)
        {
            int idx = Arrays.binarySearch(availableProtocols, preferredProtocols[i]);
            if(idx >= 0)
                aa.add(preferredProtocols[i]);
        }

        return aa.toArray(new String[0]);
    }

    protected String[] GetCipherList()
    {
        String[] preferredCiphers = {

            // *_CHACHA20_POLY1305 are 3x to 4x faster than existing cipher suites.
            //   http://googleonlinesecurity.blogspot.com/2014/04/speeding-up-and-strengthening-https.html
            // Use them if available. Normative names can be found at (TLS spec depends on IPSec spec):
            //   http://tools.ietf.org/html/draft-nir-ipsecme-chacha20-poly1305-01
            //   http://tools.ietf.org/html/draft-mavrogiannopoulos-chacha-tls-02
            "TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305",
            "TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305",
            "TLS_ECDHE_ECDSA_WITH_CHACHA20_SHA",
            "TLS_ECDHE_RSA_WITH_CHACHA20_SHA",

            "TLS_DHE_RSA_WITH_CHACHA20_POLY1305",
            "TLS_RSA_WITH_CHACHA20_POLY1305",
            "TLS_DHE_RSA_WITH_CHACHA20_SHA",
            "TLS_RSA_WITH_CHACHA20_SHA",

            // Done with bleeding edge, back to TLS v1.2 and below
            "TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384",
            "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384",
            "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256",
            "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256",

            "TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384",
            "TLS_DHE_DSS_WITH_AES_256_GCM_SHA384",
            "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256",
            "TLS_DHE_DSS_WITH_AES_128_GCM_SHA256",

            // TLS v1.0 (with some SSLv3 interop)
            "TLS_DHE_RSA_WITH_AES_256_CBC_SHA384",
            "TLS_DHE_DSS_WITH_AES_256_CBC_SHA256",
            "TLS_DHE_RSA_WITH_AES_128_CBC_SHA",
            "TLS_DHE_DSS_WITH_AES_128_CBC_SHA",

            "TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA",
            "TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA",
            "SSL_DH_RSA_WITH_3DES_EDE_CBC_SHA",
            "SSL_DH_DSS_WITH_3DES_EDE_CBC_SHA",

            // RSA key transport sucks, but they are needed as a fallback.
            // For example, microsoft.com fails under all versions of TLS
            // if they are not included. If only TLS 1.0 is available at
            // the client, then google.com will fail too. TLS v1.3 is
            // trying to deprecate them, so it will be interesteng to see
            // what happens.
            "TLS_RSA_WITH_AES_256_CBC_SHA256",
            "TLS_RSA_WITH_AES_256_CBC_SHA",
            "TLS_RSA_WITH_AES_128_CBC_SHA256",
            "TLS_RSA_WITH_AES_128_CBC_SHA"
        };

        String[] availableCiphers = null;

        try
        {
            SSLSocketFactory factory = m_ctx.getSocketFactory();
            availableCiphers = factory.getSupportedCipherSuites();
            Arrays.sort(availableCiphers);
        }
        catch(Exception e)
        {
            return new String[] {
                "TLS_DHE_DSS_WITH_AES_128_CBC_SHA",
                "TLS_DHE_DSS_WITH_AES_256_CBC_SHA",
                "TLS_DHE_RSA_WITH_AES_128_CBC_SHA",
                "TLS_DHE_RSA_WITH_AES_256_CBC_SHA",
                "TLS_RSA_WITH_AES_256_CBC_SHA256",
                "TLS_RSA_WITH_AES_256_CBC_SHA",
                "TLS_RSA_WITH_AES_128_CBC_SHA256",
                "TLS_RSA_WITH_AES_128_CBC_SHA",
                "TLS_EMPTY_RENEGOTIATION_INFO_SCSV"
            };
        }

        List<String> aa = new ArrayList<String>();
        for(int i = 0; i < preferredCiphers.length; i++)
        {
            int idx = Arrays.binarySearch(availableCiphers, preferredCiphers[i]);
            if(idx >= 0)
                aa.add(preferredCiphers[i]);
        }

        aa.add("TLS_EMPTY_RENEGOTIATION_INFO_SCSV");

        return aa.toArray(new String[0]);
    }

    private SSLContext m_ctx;

    private String[] m_ciphers;
    private String[] m_protocols;
}

关于java - 为 SSL 套接字启用哪些密码套件？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/1037590/