Store RSA in a PEM file instead of xml

- RsaKeyGenerator automatically saves the RSA keys in a PEM file
- Corrects key bit size suggestion

.gitignore

@@ -10,7 +10,7 @@
 *.iml
 
 /data/fs
-/data/rsa.xml
+/data/rsa.pem
 /data/savedGames
 /lib/
 */target/

data/rsa.xml.dist

@@ -1,5 +0,0 @@
-<rsa>
-    <!-- Generate keys with RsaKeyGenerator and place them here -->
-    <modulus></modulus>
-    <private-exponent></private-exponent>
-</rsa>

net/src/main/org/apollo/net/NetworkConstants.java

@@ -1,14 +1,21 @@
 package org.apollo.net;
 
 import java.io.FileInputStream;
+import java.io.FileReader;
 import java.io.IOException;
 import java.io.InputStream;
 import java.math.BigInteger;
-
-import org.apollo.util.xml.XmlNode;
-import org.apollo.util.xml.XmlParser;
+import java.security.KeyFactory;
+import java.security.Security;
+import java.security.interfaces.RSAPrivateKey;
+import java.security.spec.PKCS8EncodedKeySpec;
 
 import com.google.common.base.Preconditions;
+import org.apollo.util.xml.XmlNode;
+import org.apollo.util.xml.XmlParser;
+import org.bouncycastle.jce.provider.BouncyCastleProvider;
+import org.bouncycastle.util.io.pem.PemObject;
+import org.bouncycastle.util.io.pem.PemReader;
 
 /**
  * Holds various network-related constants such as port numbers.
@@ -68,20 +75,18 @@ public final class NetworkConstants {
 			throw new ExceptionInInitializerError(new IOException("Error parsing net.xml.", exception));
 		}
 
-		try (InputStream is = new FileInputStream("data/rsa.xml")) {
-			XmlNode rsa = new XmlParser().parse(is);
-			if (!rsa.getName().equals("rsa")) {
-				throw new IOException("Root node name is not 'rsa'.");
-			}
+		try (PemReader pemReader = new PemReader(new FileReader("data/rsa.pem"))) {
+			PemObject pem = pemReader.readPemObject();
+			PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(pem.getContent());
 
-			XmlNode modulus = rsa.getChild("modulus"), exponent = rsa.getChild("private-exponent");
-			Preconditions.checkState(modulus != null && exponent != null, "Rsa node must have two children: 'modulus' and 'private-exponent'.");
+			Security.addProvider(new BouncyCastleProvider());
+			KeyFactory factory = KeyFactory.getInstance("RSA", "BC");
 
-			Preconditions.checkState(modulus.getValue() != null && exponent.getValue() != null, "Value missing for 'modulus' or 'private-exponent'");
-			RSA_MODULUS = new BigInteger(modulus.getValue());
-			RSA_EXPONENT = new BigInteger(exponent.getValue());
+			RSAPrivateKey privateKey = (RSAPrivateKey) factory.generatePrivate(keySpec);
+			RSA_MODULUS = privateKey.getModulus();
+			RSA_EXPONENT = privateKey.getPrivateExponent();
 		} catch (Exception exception) {
-			throw new ExceptionInInitializerError(new IOException("Error parsing rsa.xml", exception));
+			throw new ExceptionInInitializerError(new IOException("Error parsing id_rsa", exception));
 		}
 	}
 

pom.xml

@@ -81,6 +81,12 @@
       <version>0.9.5.2</version>
     </dependency>
 
+    <dependency>
+      <groupId>org.bouncycastle</groupId>
+      <artifactId>bcprov-jdk15on</artifactId>
+      <version>1.54</version>
+    </dependency>
+
     <dependency>
       <groupId>junit</groupId>
       <artifactId>junit</artifactId>
@@ -101,6 +107,7 @@
       <version>1.6.4</version>
       <scope>test</scope>
     </dependency>
+
   </dependencies>
 
 </project>

util/pom.xml

@@ -22,4 +22,12 @@
     <sourceDirectory>src/main</sourceDirectory>
     <testSourceDirectory>src/test</testSourceDirectory>
   </build>
+
+  <dependencies>
+    <dependency>
+      <groupId>org.bouncycastle</groupId>
+      <artifactId>bcprov-jdk15on</artifactId>
+    </dependency>
+  </dependencies>
+
 </project>

util/src/main/org/apollo/util/tools/RsaKeyGenerator.java

@@ -1,45 +1,62 @@
 package org.apollo.util.tools;
 
-import java.math.BigInteger;
-import java.security.SecureRandom;
-import java.util.Random;
+import java.io.FileWriter;
+import java.security.KeyPair;
+import java.security.KeyPairGenerator;
+import java.security.Security;
+import java.security.interfaces.RSAPrivateKey;
+import java.security.interfaces.RSAPublicKey;
+
+import org.bouncycastle.jce.provider.BouncyCastleProvider;
+import org.bouncycastle.util.io.pem.PemObject;
+import org.bouncycastle.util.io.pem.PemWriter;
 
 /**
  * An RSA key generator.
  *
  * @author Graham
  * @author Major
+ * @author Cube
  */
 public final class RsaKeyGenerator {
 
 	/**
-	 * The bit count. <strong>Strongly</strong> recommended to be at least 2,048.
+	 * The bit count.
+	 * <strong>Note:</strong> 2048 bits and above are not compatible with the client without modifications
 	 */
-	private static final int BIT_COUNT = 2_048;
+	private static final int BIT_COUNT = 1024;
+
+	/**
+	 * The path to the private key file.
+	 */
+	private static final String PRIVATE_KEY_FILE = "data/rsa.pem";
 
 	/**
 	 * The entry point of the RsaKeyGenerator.
 	 *
 	 * @param args The application arguments.
 	 */
-	public static void main(String[] args) {
-		Random random = new SecureRandom();
+	public static void main(String[] args) throws Exception {
+		Security.addProvider(new BouncyCastleProvider());
 
-		BigInteger publicKey = BigInteger.valueOf(65_537);
-		BigInteger p, q, phi, modulus, privateKey;
+		KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA", "BC");
+		keyPairGenerator.initialize(BIT_COUNT);
+		KeyPair keyPair = keyPairGenerator.generateKeyPair();
 
-		do {
-			p = BigInteger.probablePrime(BIT_COUNT / 2, random);
-			q = BigInteger.probablePrime(BIT_COUNT / 2, random);
-			phi = p.subtract(BigInteger.ONE).multiply(q.subtract(BigInteger.ONE));
+		RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
+		RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
 
-			modulus = p.multiply(q);
-			privateKey = publicKey.modInverse(phi);
-		} while (modulus.bitLength() != BIT_COUNT || privateKey.bitLength() != BIT_COUNT || !phi.gcd(publicKey).equals(BigInteger.ONE));
+		System.out.println("Place these keys in the client:");
+		System.out.println("--------------------");
+		System.out.println("public key: " + publicKey.getPublicExponent());
+		System.out.println("modulus: " + publicKey.getModulus());
 
-		System.out.println("modulus: " + modulus);
-		System.out.println("public key: " + publicKey);
-		System.out.println("private key: " + privateKey);
+		try (PemWriter writer = new PemWriter(new FileWriter(PRIVATE_KEY_FILE))) {
+			writer.writeObject(new PemObject("RSA PRIVATE KEY", privateKey.getEncoded()));
+		} catch (Exception e) {
+			System.err.println("Failed to write private key to " + PRIVATE_KEY_FILE);
+			e.printStackTrace();
+		}
 	}
 
 }