有關SSL的原理和介紹在網上已經有不少，對于Java下使用keytool生成證書，配置SSL通信的教程也非常多。但如果我們不能夠親自動手做一個SSL Sever和SSL Client，可能就永遠也不能深入地理解Java環境下，SSL的通信是如何實現的。對SSL中的各種概念的認識也可能會僅限于可以使用的程度。本文通過構造一個簡單的SSL Server和SSL Client來講解Java環境下SSL的通信原理。
首先我們先回顧一下常規的Java Socket編程。在Java下寫一個Socket服務器和客戶端的例子還是比較簡單的。以下是服務端的代碼：
Java代碼
1.package org.bluedash.tryssl;
2.
3.import java.io.BufferedReader;
4.import java.io.IOException;
5.import java.io.InputStbreamReader;
6.import java.io.PrintWriter;
7.import java.net.ServerSocket;
8.import java.net.Socket;
9.
10.public class Server extends Thread {
11. private Socket socket;
12.
13. public Server(Socket socket) {
14. this.socket = socket;
15. }
16.
17. public void run() {
18. try {
19. BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
20. PrintWriter writer = new PrintWriter(socket.getOutputStream());
21.
22. String data = reader.readLine();
23. writer.println(data);
24. writer.close();
25. socket.close();
26. } catch (IOException e) {
27.
28. }
29. }
30.
31. public static void main(String[] args) throws Exception {
32. while (true) {
33. new Server((new ServerSocket(8080)).accept()).start();
34. }
35. }
36.}
package org.bluedash.tryssl;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
public class Server extends Thread {
private Socket socket;
public Server(Socket socket) {
this.socket = socket;
}
public void run() {
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
PrintWriter writer = new PrintWriter(socket.getOutputStream());
String data = reader.readLine();
writer.println(data);
writer.close();
socket.close();
} catch (IOException e) {
}
}
public static void main(String[] args) throws Exception {
while (true) {
new Server((new ServerSocket(8080)).accept()).start();
}
}
}
服務端很簡單：偵聽8080端口，并把客戶端發來的字符串返回去。下面是客戶端的代碼：
Java代碼
1.package org.bluedash.tryssl;
2.
3.import java.io.BufferedReader;
4.import java.io.InputStreamReader;
5.import java.io.PrintWriter;
6.import java.net.Socket;
7.
8.public class Client {
9.
10. public static void main(String[] args) throws Exception {
11.
12. Socket s = new Socket("localhost", 8080);
13.
14. PrintWriter writer = new PrintWriter(s.getOutputStream());
15. BufferedReader reader = new BufferedReader(new InputStreamReader(s.getInputStream()));
16. writer.println("hello");
17. writer.flush();
18. System.out.println(reader.readLine());
19. s.close();
20. }
21.
22.}
package org.bluedash.tryssl;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
public class Client {
public static void main(String[] args) throws Exception {
Socket s = new Socket("localhost", 8080);
PrintWriter writer = new PrintWriter(s.getOutputStream());
BufferedReader reader = new BufferedReader(new InputStreamReader(s.getInputStream()));
writer.println("hello");
writer.flush();
System.out.println(reader.readLine());
s.close();
}
}
客戶端也非常簡單：向服務端發起請求，發送一個"hello"字串，然后獲得服務端的返回。把服務端運行起來后，執行客戶端，我們將得到"hello"的返回。
就是這樣一套簡單的網絡通信的代碼，我們來把它改造成使用SSL通信。在SSL通信協議中，我們都知道首先服務端必須有一個數字證書，當客戶端連接到服務端時，會得到這個證書，然后客戶端會判斷這個證書是否是可信的，如果是，則交換信道加密密鑰，進行通信。如果不信任這個證書，則連接失敗。
因此，我們首先要為服務端生成一個數字證書。Java環境下，數字證書是用keytool生成的，這些證書被存儲在store的概念中，就是證書倉庫。我們來調用keytool命令為服務端生成數字證書和保存它使用的證書倉庫：
Bash代碼
1.keytool -genkey -v -alias bluedash-ssl-demo-server -keyalg RSA -keystore ./server_ks -dname "CN=localhost,OU=cn,O=cn,L=cn,ST=cn,C=cn" -storepass server -keypass 123123
keytool -genkey -v -alias bluedash-ssl-demo-server -keyalg RSA -keystore ./server_ks -dname "CN=localhost,OU=cn,O=cn,L=cn,ST=cn,C=cn" -storepass server -keypass 123123
這樣，我們就將服務端證書bluedash-ssl-demo-server保存在了server_ksy這個store文件當中。有關keytool的用法在本文中就不再多贅述。執行上面的命令得到如下結果：
Bash代碼
1.Generating 1,024 bit RSA key pair and self-signed certificate (SHA1withRSA) with a validity of 90 days
2. for: CN=localhost, OU=cn, O=cn, L=cn, ST=cn, C=cn
3.[Storing ./server_ks]
Generating 1,024 bit RSA key pair and self-signed certificate (SHA1withRSA) with a validity of 90 days
for: CN=localhost, OU=cn, O=cn, L=cn, ST=cn, C=cn
[Storing ./server_ks]
然后，改造我們的服務端代碼，讓服務端使用這個證書，并提供SSL通信：
Java代碼
1.package org.bluedash.tryssl;
2.
3.import java.io.BufferedReader;
4.import java.io.FileInputStream;
5.import java.io.IOException;
6.import java.io.InputStreamReader;
7.import java.io.PrintWriter;
8.import java.net.ServerSocket;
9.import java.net.Socket;
10.import java.security.KeyStore;
11.
12.import javax.net.ServerSocketFactory;
13.import javax.net.ssl.KeyManagerFactory;
14.import javax.net.ssl.SSLContext;
15.import javax.net.ssl.SSLServerSocket;
16.
17.public class SSLServer extends Thread {
18. private Socket socket;
19.
20. public SSLServer(Socket socket) {
21. this.socket = socket;
22. }
23.
24. public void run() {
25. try {
26. BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
27. PrintWriter writer = new PrintWriter(socket.getOutputStream());
28.
29. String data = reader.readLine();
30. writer.println(data);
31. writer.close();
32. socket.close();
33. } catch (IOException e) {
34.
35. }
36. }
37.
38. private static String SERVER_KEY_STORE = "/Users/liweinan/projs/ssl/src/main/resources/META-INF/server_ks";
39. private static String SERVER_KEY_STORE_PASSWORD = "123123";
40.
41. public static void main(String[] args) throws Exception {
42. System.setProperty("javax.net.ssl.trustStore", SERVER_KEY_STORE);
43. SSLContext context = SSLContext.getInstance("TLS");
44.
45. KeyStore ks = KeyStore.getInstance("jceks");
46. ks.load(new FileInputStream(SERVER_KEY_STORE), null);
47. KeyManagerFactory kf = KeyManagerFactory.getInstance("SunX509");
48. kf.init(ks, SERVER_KEY_STORE_PASSWORD.toCharArray());
49.
50. context.init(kf.getKeyManagers(), null, null);
51.
52. ServerSocketFactory factory = context.getServerSocketFactory();
53. ServerSocket _socket = factory.createServerSocket(8443);
54. ((SSLServerSocket) _socket).setNeedClientAuth(false);
55.
56. while (true) {
57. new SSLServer(_socket.accept()).start();
58. }
59. }
60.}
package org.bluedash.tryssl;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.security.KeyStore;
import javax.net.ServerSocketFactory;
import javax.net.ssl.KeyManagerFactory;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLServerSocket;
public class SSLServer extends Thread {
private Socket socket;
public SSLServer(Socket socket) {
this.socket = socket;
}
public void run() {
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
PrintWriter writer = new PrintWriter(socket.getOutputStream());
String data = reader.readLine();
writer.println(data);
writer.close();
socket.close();
} catch (IOException e) {
}
}
private static String SERVER_KEY_STORE = "/Users/liweinan/projs/ssl/src/main/resources/META-INF/server_ks";
private static String SERVER_KEY_STORE_PASSWORD = "123123";
public static void main(String[] args) throws Exception {
System.setProperty("javax.net.ssl.trustStore", SERVER_KEY_STORE);
SSLContext context = SSLContext.getInstance("TLS");
KeyStore ks = KeyStore.getInstance("jceks");
ks.load(new FileInputStream(SERVER_KEY_STORE), null);
KeyManagerFactory kf = KeyManagerFactory.getInstance("SunX509");
kf.init(ks, SERVER_KEY_STORE_PASSWORD.toCharArray());
context.init(kf.getKeyManagers(), null, null);
ServerSocketFactory factory = context.getServerSocketFactory();
ServerSocket _socket = factory.createServerSocket(8443);
((SSLServerSocket) _socket).setNeedClientAuth(false);
while (true) {
new SSLServer(_socket.accept()).start();
}
}
}
可以看到，服務端的Socket準備設置工作大大增加了，增加的代碼的作用主要是將證書導入并進行使用。此外，所使用的Socket變成了SSLServerSocket，另外端口改到了8443（這個不是強制的，僅僅是為了遵守習慣）。另外，最重要的一點，服務端證書里面的CN一定和服務端的域名統一，我們的證書服務的域名是localhost，那么我們的客戶端在連接服務端時一定也要用localhost來連接，否則根據SSL協議標準，域名與證書的CN不匹配，說明這個證書是不安全的，通信將無法正常運行。
有了服務端，我們原來的客戶端就不能使用了，必須要走SSL協議。由于服務端的證書是我們自己生成的，沒有任何受信任機構的簽名，所以客戶端是無法驗證服務端證書的有效性的，通信必然會失敗。所以我們需要為客戶端創建一個保存所有信任證書的倉庫，然后把服務端證書導進這個倉庫。這樣，當客戶端連接服務端時，會發現服務端的證書在自己的信任列表中，就可以正常通信了。
因此現在我們要做的是生成一個客戶端的證書倉庫，因為keytool不能僅生成一個空白倉庫，所以和服務端一樣，我們還是生成一個證書加一個倉庫（客戶端證書加倉庫）：
Bash代碼
1.keytool -genkey -v -alias bluedash-ssl-demo-client -keyalg RSA -keystore ./client_ks -dname "CN=localhost,OU=cn,O=cn,L=cn,ST=cn,C=cn" -storepass client -keypass 456456
keytool -genkey -v -alias bluedash-ssl-demo-client -keyalg RSA -keystore ./client_ks -dname "CN=localhost,OU=cn,O=cn,L=cn,ST=cn,C=cn" -storepass client -keypass 456456
結果如下：
Bash代碼
1.Generating 1,024 bit RSA key pair and self-signed certificate (SHA1withRSA) with a validity of 90 days
2. for: CN=localhost, OU=cn, O=cn, L=cn, ST=cn, C=cn
3.[Storing ./client_ks]
Generating 1,024 bit RSA key pair and self-signed certificate (SHA1withRSA) with a validity of 90 days
for: CN=localhost, OU=cn, O=cn, L=cn, ST=cn, C=cn
[Storing ./client_ks]
接下來，我們要把服務端的證書導出來，并導入到客戶端的倉庫。第一步是導出服務端的證書：
Bash代碼
1.keytool -export -alias bluedash-ssl-demo-server -keystore ./server_ks -file server_key.cer
keytool -export -alias bluedash-ssl-demo-server -keystore ./server_ks -file server_key.cer
執行結果如下：
Bash代碼
1.Enter keystore password: server
2.Certificate stored in file <server_key.cer>
Enter keystore password: server
Certificate stored in file <server_key.cer>
然后是把導出的證書導入到客戶端證書倉庫：
Bash代碼
1.keytool -import -trustcacerts -alias bluedash-ssl-demo-server -file ./server_key.cer -keystore ./client_ks
keytool -import -trustcacerts -alias bluedash-ssl-demo-server -file ./server_key.cer -keystore ./client_ks
結果如下：
Bash代碼
1.Enter keystore password: client
2.Owner: CN=localhost, OU=cn, O=cn, L=cn, ST=cn, C=cn
3.Issuer: CN=localhost, OU=cn, O=cn, L=cn, ST=cn, C=cn
4.Serial number: 4c57c7de
5.Valid from: Tue Aug 03 15:40:14 CST 2010 until: Mon Nov 01 15:40:14 CST 2010
6.Certificate fingerprints:
7. MD5: FC:D4:8B:36:3F:1B:30:EA:6D:63:55:4F:C7:68:3B:0C
8. SHA1: E1:54:2F:7C:1A:50:F5:74:AA:63:1E:F9:CC:B1:1C:73:AA:34:8A:C4
9. Signature algorithm name: SHA1withRSA
10. Version: 3
11.Trust this certificate? [no]: yes
12.Certificate was added to keystore
Enter keystore password: client
Owner: CN=localhost, OU=cn, O=cn, L=cn, ST=cn, C=cn
Issuer: CN=localhost, OU=cn, O=cn, L=cn, ST=cn, C=cn
Serial number: 4c57c7de
Valid from: Tue Aug 03 15:40:14 CST 2010 until: Mon Nov 01 15:40:14 CST 2010
Certificate fingerprints:
MD5: FC:D4:8B:36:3F:1B:30:EA:6D:63:55:4F:C7:68:3B:0C
SHA1: E1:54:2F:7C:1A:50:F5:74:AA:63:1E:F9:CC:B1:1C:73:AA:34:8A:C4
Signature algorithm name: SHA1withRSA
Version: 3
Trust this certificate? [no]: yes
Certificate was added to keystore
好，準備工作做完了，我們來撰寫客戶端的代碼：
Java代碼
1.package org.bluedash.tryssl;
2.
3.import java.io.BufferedReader;
4.import java.io.InputStreamReader;
5.import java.io.PrintWriter;
6.import java.net.Socket;
7.
8.import javax.net.SocketFactory;
9.import javax.net.ssl.SSLSocketFactory;
10.
11.public class SSLClient {
12.
13. private static String CLIENT_KEY_STORE = "/Users/liweinan/projs/ssl/src/main/resources/META-INF/client_ks";
14.
15. public static void main(String[] args) throws Exception {
16. // Set the key store to use for validating the server cert.
17. System.setProperty("javax.net.ssl.trustStore", CLIENT_KEY_STORE);
18.
19. System.setProperty("javax.net.debug", "ssl,handshake");
20.
21. SSLClient client = new SSLClient();
22. Socket s = client.clientWithoutCert();
23.
24. PrintWriter writer = new PrintWriter(s.getOutputStream());
25. BufferedReader reader = new BufferedReader(new InputStreamReader(s
26. .getInputStream()));
27. writer.println("hello");
28. writer.flush();
29. System.out.println(reader.readLine());
30. s.close();
31. }
32.
33. private Socket clientWithoutCert() throws Exception {
34. SocketFactory sf = SSLSocketFactory.getDefault();
35. Socket s = sf.createSocket("localhost", 8443);
36. return s;
37. }
38.}
package org.bluedash.tryssl;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import javax.net.SocketFactory;
import javax.net.ssl.SSLSocketFactory;
public class SSLClient {
private static String CLIENT_KEY_STORE = "/Users/liweinan/projs/ssl/src/main/resources/META-INF/client_ks";
public static void main(String[] args) throws Exception {
// Set the key store to use for validating the server cert.
System.setProperty("javax.net.ssl.trustStore", CLIENT_KEY_STORE);
System.setProperty("javax.net.debug", "ssl,handshake");
SSLClient client = new SSLClient();
Socket s = client.clientWithoutCert();
PrintWriter writer = new PrintWriter(s.getOutputStream());
BufferedReader reader = new BufferedReader(new InputStreamReader(s
.getInputStream()));
writer.println("hello");
writer.flush();
System.out.println(reader.readLine());
s.close();
}
private Socket clientWithoutCert() throws Exception {
SocketFactory sf = SSLSocketFactory.getDefault();
Socket s = sf.createSocket("localhost", 8443);
return s;
}
}
可以看到，除了把一些類變成SSL通信類以外，客戶端也多出了使用信任證書倉庫的代碼。以上，我們便完成了SSL單向握手通信。即：客戶端驗證服務端的證書，服務端不認證客戶端的證書。
以上便是Java環境下SSL單向握手的全過程。因為我們在客戶端設置了日志輸出級別為DEBUG：
Java代碼
1.System.setProperty("javax.net.debug", "ssl,handshake");
System.setProperty("javax.net.debug", "ssl,handshake");
因此我們可以看到SSL通信的全過程，這些日志可以幫助我們更具體地了解通過SSL協議建立網絡連接時的全過程。
結合日志，我們來看一下SSL雙向認證的全過程：
第一步: 客戶端發送ClientHello消息，發起SSL連接請求，告訴服務器自己支持的SSL選項（加密方式等）。
Bash代碼
1.*** ClientHello, TLSv1
*** ClientHello, TLSv1
第二步: 服務器響應請求，回復ServerHello消息，和客戶端確認SSL加密方式：
Bash代碼
1.*** ServerHello, TLSv1
*** ServerHello, TLSv1
第三步: 服務端向客戶端發布自己的公鑰。
第四步: 客戶端與服務端的協通溝通完畢，服務端發送ServerHelloDone消息：
Bash代碼
1.*** ServerHelloDone
*** ServerHelloDone
第五步: 客戶端使用服務端給予的公鑰，創建會話用密鑰（SSL證書認證完成后，為了提高性能，所有的信息交互就可能會使用對稱加密算法），并通過ClientKeyExchange消息發給服務器：
Bash代碼
1.*** ClientKeyExchange, RSA PreMasterSecret, TLSv1
*** ClientKeyExchange, RSA PreMasterSecret, TLSv1
第六步： 客戶端通知服務器改變加密算法，通過ChangeCipherSpec消息發給服務端：
Bash代碼
1.main, WRITE: TLSv1 Change Cipher Spec, length = 1
main, WRITE: TLSv1 Change Cipher Spec, length = 1
第七步： 客戶端發送Finished消息，告知服務器請檢查加密算法的變更請求：
Bash代碼
1.*** Finished
*** Finished
第八步：服務端確認算法變更，返回ChangeCipherSpec消息
Bash代碼
1.main, READ: TLSv1 Change Cipher Spec, length = 1
main, READ: TLSv1 Change Cipher Spec, length = 1
第九步：服務端發送Finished消息，加密算法生效：
Bash代碼
1.*** Finished
*** Finished
那么如何讓服務端也認證客戶端的身份，即雙向握手呢？其實很簡單，在服務端代碼中，把這一行：
Java代碼
1.((SSLServerSocket) _socket).setNeedClientAuth(false);
((SSLServerSocket) _socket).setNeedClientAuth(false);
改成：
Java代碼
1.((SSLServerSocket) _socket).setNeedClientAuth(true);
((SSLServerSocket) _socket).setNeedClientAuth(true);
就可以了。但是，同樣的道理，現在服務端并沒有信任客戶端的證書，因為客戶端的證書也是自己生成的。所以，對于服務端，需要做同樣的工作：把客戶端的證書導出來，并導入到服務端的證書倉庫：
Bash代碼
1.keytool -export -alias bluedash-ssl-demo-client -keystore ./client_ks -file client_key.cer
2.Enter keystore password: client
3.Certificate stored in file <client_key.cer>
keytool -export -alias bluedash-ssl-demo-client -keystore ./client_ks -file client_key.cer
Enter keystore password: client
Certificate stored in file <client_key.cer>
Bash代碼
1.keytool -import -trustcacerts -alias bluedash-ssl-demo-client -file ./client_key.cer -keystore ./server_ks
2.Enter keystore password: server
3.Owner: CN=localhost, OU=cn, O=cn, L=cn, ST=cn, C=cn
4.Issuer: CN=localhost, OU=cn, O=cn, L=cn, ST=cn, C=cn
5.Serial number: 4c57c80b
6.Valid from: Tue Aug 03 15:40:59 CST 2010 until: Mon Nov 01 15:40:59 CST 2010
7.Certificate fingerprints:
8. MD5: DB:91:F4:1E:65:D1:81:F2:1E:A6:A3:55:3F:E8:12:79
9. SHA1: BF:77:56:61:04:DD:95:FC:E5:84:48:5C:BE:60:AF:02:96:A2:E1:E2
10. Signature algorithm name: SHA1withRSA
11. Version: 3
12.Trust this certificate? [no]: yes
13.Certificate was added to keystore
keytool -import -trustcacerts -alias bluedash-ssl-demo-client -file ./client_key.cer -keystore ./server_ks
Enter keystore password: server
Owner: CN=localhost, OU=cn, O=cn, L=cn, ST=cn, C=cn
Issuer: CN=localhost, OU=cn, O=cn, L=cn, ST=cn, C=cn
Serial number: 4c57c80b
Valid from: Tue Aug 03 15:40:59 CST 2010 until: Mon Nov 01 15:40:59 CST 2010
Certificate fingerprints:
MD5: DB:91:F4:1E:65:D1:81:F2:1E:A6:A3:55:3F:E8:12:79
SHA1: BF:77:56:61:04:DD:95:FC:E5:84:48:5C:BE:60:AF:02:96:A2:E1:E2
Signature algorithm name: SHA1withRSA
Version: 3
Trust this certificate? [no]: yes
Certificate was added to keystore
完成了證書的導入，還要在客戶端需要加入一段代碼，用于在連接時，客戶端向服務端出示自己的證書：
Java代碼
1.package org.bluedash.tryssl;
2.
3.import java.io.BufferedReader;
4.import java.io.FileInputStream;
5.import java.io.InputStreamReader;
6.import java.io.PrintWriter;
7.import java.net.Socket;
8.import java.security.KeyStore;
9.import javax.net.SocketFactory;
10.import javax.net.ssl.KeyManagerFactory;
11.import javax.net.ssl.SSLContext;
12.import javax.net.ssl.SSLSocketFactory;
13.
14.public class SSLClient {
15. private static String CLIENT_KEY_STORE = "/Users/liweinan/projs/ssl/src/main/resources/META-INF/client_ks";
16. private static String CLIENT_KEY_STORE_PASSWORD = "456456";
17.
18. public static void main(String[] args) throws Exception {
19. // Set the key store to use for validating the server cert.
20. System.setProperty("javax.net.ssl.trustStore", CLIENT_KEY_STORE);
21. System.setProperty("javax.net.debug", "ssl,handshake");
22. SSLClient client = new SSLClient();
23. Socket s = client.clientWithCert();
24.
25. PrintWriter writer = new PrintWriter(s.getOutputStream());
26. BufferedReader reader = new BufferedReader(new InputStreamReader(s.getInputStream()));
27. writer.println("hello");
28. writer.flush();
29. System.out.println(reader.readLine());
30. s.close();
31. }
32.
33. private Socket clientWithoutCert() throws Exception {
34. SocketFactory sf = SSLSocketFactory.getDefault();
35. Socket s = sf.createSocket("localhost", 8443);
36. return s;
37. }
38.
39. private Socket clientWithCert() throws Exception {
40. SSLContext context = SSLContext.getInstance("TLS");
41. KeyStore ks = KeyStore.getInstance("jceks");
42.
43. ks.load(new FileInputStream(CLIENT_KEY_STORE), null);
44. KeyManagerFactory kf = KeyManagerFactory.getInstance("SunX509");
45. kf.init(ks, CLIENT_KEY_STORE_PASSWORD.toCharArray());
46. context.init(kf.getKeyManagers(), null, null);
47.
48. SocketFactory factory = context.getSocketFactory();
49. Socket s = factory.createSocket("localhost", 8443);
50. return s;
51. }
52.}
package org.bluedash.tryssl;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import java.security.KeyStore;
import javax.net.SocketFactory;
import javax.net.ssl.KeyManagerFactory;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSocketFactory;
public class SSLClient {
private static String CLIENT_KEY_STORE = "/Users/liweinan/projs/ssl/src/main/resources/META-INF/client_ks";
private static String CLIENT_KEY_STORE_PASSWORD = "456456";
public static void main(String[] args) throws Exception {
// Set the key store to use for validating the server cert.
System.setProperty("javax.net.ssl.trustStore", CLIENT_KEY_STORE);
System.setProperty("javax.net.debug", "ssl,handshake");
SSLClient client = new SSLClient();
Socket s = client.clientWithCert();
PrintWriter writer = new PrintWriter(s.getOutputStream());
BufferedReader reader = new BufferedReader(new InputStreamReader(s.getInputStream()));
writer.println("hello");
writer.flush();
System.out.println(reader.readLine());
s.close();
}
private Socket clientWithoutCert() tbhrows Exception {
SocketFactory sf = SSLSocketFactory.getDefault();
Socket s = sf.createSocket("localhost", 8443);
return s;
}
private Socket clientWithCert() throws Exception {
SSLContext context = SSLContext.getInstance("TLS");
KeyStore ks = KeyStore.getInstance("jceks");
ks.load(new FileInputStream(CLIENT_KEY_STORE), null);
KeyManagerFactory kf = KeyManagerFactory.getInstance("SunX509");
kf.init(ks, CLIENT_KEY_STORE_PASSWORD.toCharArray());
context.init(kf.getKeyManagers(), null, null);
SocketFactory factory = context.getSocketFactory();
Socket s = factory.createSocket("localhost", 8443);
return s;
}
}
通過比對單向認證的日志輸出，我們可以發現雙向認證時，多出了服務端認證客戶端證書的步驟：
Bash代碼
1.*** CertificateRequest
2.Cert Types: RSA, DSS
3.Cert Authorities:
4.<CN=localhost, OU=cn, O=cn, L=cn, ST=cn, C=cn>
5.<CN=localhost, OU=cn, O=cn, L=cn, ST=cn, C=cn>
6.*** ServerHelloDone
*** CertificateRequest
Cert Types: RSA, DSS
Cert Authorities:
<CN=localhost, OU=cn, O=cn, L=cn, ST=cn, C=cn>
<CN=localhost, OU=cn, O=cn, L=cn, ST=cn, C=cn>
*** ServerHelloDone
Bash代碼
1.*** CertificateVerify
2.main, WRITE: TLSv1 Handshake, length = 134
3.main, WRITE: TLSv1 Change Cipher Spec, length = 1
*** CertificateVerify
main, WRITE: TLSv1 Handshake, length = 134
main, WRITE: TLSv1 Change Cipher Spec, length = 1
在 @*** ServerHelloDone@ 之前，服務端向客戶端發起了需要證書的請求 @*** CertificateRequest@ 。
在客戶端向服務端發出 @Change Cipher Spec@ 請求之前，多了一步客戶端證書認證的過程 @*** CertificateVerify@ 。
客戶端與服務端互相認證證書的情景