Add RSA key generator.

src/org/apollo/tools/RsaKeyGenerator.java

@@ -0,0 +1,46 @@
+package org.apollo.tools;
+
+import java.math.BigInteger;
+import java.security.SecureRandom;
+import java.util.Random;
+
+/**
+ * An RSA key generator.
+ *
+ * @author Graham
+ * @author Major
+ */
+public final class RsaKeyGenerator {
+
+	/**
+	 * The bit count. <strong>Strongly</strong> recommended to be at least 2,048.
+	 */
+	private static final int BIT_COUNT = 2_048;
+
+	/**
+	 * The entry point of the RsaKeyGenerator.
+	 * 
+	 * @param args The application arguments.
+	 */
+	public static void main(String[] args) {
+		Random random = new SecureRandom();
+
+		BigInteger publicKey = BigInteger.valueOf(65535);
+		BigInteger p, q, phi, modulus, privateKey;
+
+		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));
+
+			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("modulus: " + modulus);
+		System.out.println("public key: " + publicKey);
+		System.out.println("private key: " + privateKey);
+	}
+
+}