refactored a AES-128 key generation function

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@18382 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/Util.java

@@ -16,6 +16,8 @@ import org.apache.commons.lang.time.FastDateFormat;
 import org.kohsuke.stapler.Stapler;
 import org.jvnet.animal_sniffer.IgnoreJRERequirement;
 
+import javax.crypto.SecretKey;
+import javax.crypto.spec.SecretKeySpec;
 import java.io.BufferedReader;
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
@@ -30,6 +32,7 @@ import java.io.Writer;
 import java.io.PrintStream;
 import java.io.InputStreamReader;
 import java.io.FileInputStream;
+import java.io.UnsupportedEncodingException;
 import java.net.InetAddress;
 import java.net.UnknownHostException;
 import java.net.URI;
@@ -458,6 +461,26 @@ public class Util {
         }
     }
 
+    /**
+     * Covnerts a string into 128-bit AES key.
+     * @since 1.308
+     */
+    public static SecretKey toAes128Key(String s) {
+        try {
+            // turn secretKey into 256 bit hash
+            MessageDigest digest = MessageDigest.getInstance("SHA-256");
+            digest.reset();
+            digest.update(s.getBytes("UTF-8"));
+
+            // Due to the stupid US export restriction JDK only ships 128bit version.
+            return new SecretKeySpec(digest.digest(),0,128/8, "AES");
+        } catch (NoSuchAlgorithmException e) {
+            throw new Error(e);
+        } catch (UnsupportedEncodingException e) {
+            throw new Error(e);
+        }
+    }
+
     public static String toHexString(byte[] data, int start, int len) {
         StringBuilder buf = new StringBuilder();
         for( int i=0; i<len; i++ ) {

core/src/main/java/hudson/model/Hudson.java

@@ -156,8 +156,11 @@ import java.io.InputStream;
 import java.io.Serializable;
 import java.io.PrintStream;
 import java.io.OutputStream;
+import java.io.UnsupportedEncodingException;
 import java.net.URL;
 import java.security.SecureRandom;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
 import java.text.NumberFormat;
 import java.text.ParseException;
 import java.text.Collator;
@@ -197,6 +200,8 @@ import java.util.logging.Logger;
 import java.util.regex.Pattern;
 import java.nio.charset.Charset;
 import javax.servlet.RequestDispatcher;
+import javax.crypto.spec.SecretKeySpec;
+import javax.crypto.SecretKey;
 
 import groovy.lang.GroovyShell;
 
@@ -685,6 +690,14 @@ public final class Hudson extends Node implements ItemGroup<TopLevelItem>, Stapl
         return secretKey;
     }
 
+    /**
+     * Gets {@linkplain #getSecretKey() the secret key} as a key for AES-128.
+     * @since 1.308
+     */
+    public SecretKey getSecretKeyAsAES128() {
+        return Util.toAes128Key(secretKey);
+    }
+
     /**
      * Gets the SCM descriptor by name. Primarily used for making them web-visible.
      */

core/src/main/java/hudson/util/Secret.java

@@ -30,14 +30,13 @@ import com.thoughtworks.xstream.io.HierarchicalStreamReader;
 import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
 import com.trilead.ssh2.crypto.Base64;
 import hudson.model.Hudson;
+import hudson.Util;
 
 import javax.crypto.SecretKey;
 import javax.crypto.Cipher;
-import javax.crypto.spec.SecretKeySpec;
 import java.io.UnsupportedEncodingException;
 import java.io.IOException;
 import java.security.GeneralSecurityException;
-import java.security.MessageDigest;
 
 /**
  * Glorified {@link String} that uses encryption in the persisted form, to avoid accidental exposure of a secret.
@@ -80,15 +79,8 @@ public final class Secret {
      */
     private static SecretKey getKey() throws UnsupportedEncodingException, GeneralSecurityException {
         String secret = SECRET;
-        if(secret==null)    secret = Hudson.getInstance().getSecretKey();
-
-        // turn secretKey into 256 bit hash
-        MessageDigest digest = MessageDigest.getInstance("SHA-256");
-        digest.reset();
-        digest.update(secret.getBytes("UTF-8"));
-
-        // Due to the stupid US export restriction JDK only ships 128bit version.
-        return new SecretKeySpec(digest.digest(),0,128/8, "AES");
+        if(secret==null)    return Hudson.getInstance().getSecretKeyAsAES128();
+        return Util.toAes128Key(secret);
     }
 
     /**