Data commit

Task/RSA-code/Java/rsa-code-1.java

@@ -0,0 +1,27 @@
+public static void main(String[] args) {
+    /*
+    This is probably not the best method...or even the most optimized way...however it works since n and d are too big to be ints or longs
+    This was also only tested with 'Rosetta Code' and 'Hello World'
+    It's also pretty limited on plainText size (anything bigger than the above will fail)
+    */
+    BigInteger n = new BigInteger("9516311845790656153499716760847001433441357");
+    BigInteger e = new BigInteger("65537");
+    BigInteger d = new BigInteger("5617843187844953170308463622230283376298685");
+    Charset c = Charsets.UTF_8;
+    String plainText = "Rosetta Code";
+    System.out.println("PlainText : " + plainText);
+    byte[] bytes = plainText.getBytes();
+    BigInteger plainNum = new BigInteger(bytes);
+    System.out.println("As number : " + plainNum);
+    BigInteger Bytes = new BigInteger(bytes);
+    if (Bytes.compareTo(n) == 1) {
+        System.out.println("Plaintext is too long");
+        return;
+    }
+    BigInteger enc = plainNum.modPow(e, n);
+    System.out.println("Encoded: " + enc);
+    BigInteger dec = enc.modPow(d, n);
+    System.out.println("Decoded: " + dec);
+    String decText = new String(dec.toByteArray(), c);
+    System.out.println("As text: " + decText);
+}

Task/RSA-code/Java/rsa-code-2.java

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+import java.math.BigInteger;
+import java.util.Random;
+
+public class rsaCode {
+    public static void main(String[]args){
+        //Size of primes
+        int BIT_LENGTH = 4096;
+        Random rand = new Random();
+        //Generate primes and other necessary values
+        BigInteger p = BigInteger.probablePrime(BIT_LENGTH / 2, rand);
+        BigInteger q = BigInteger.probablePrime(BIT_LENGTH / 2, rand);
+        BigInteger n = p.multiply(q);
+        BigInteger phi = p.subtract(BigInteger.valueOf(1)).multiply(q.subtract(BigInteger.valueOf(1)));
+        BigInteger e;
+        BigInteger d;
+        do {
+            e = new BigInteger(phi.bitLength(), rand);
+        } while (e.compareTo(BigInteger.valueOf(1)) <= 0 || e.compareTo(phi) >= 0 || !e.gcd(phi).equals(BigInteger.valueOf(1)));
+        d = e.modInverse(phi);
+        //Convert message to byte array and then to a BigInteger
+        BigInteger message = new BigInteger("Hello World! - From Rosetta Code".getBytes());
+        BigInteger cipherText = message.modPow(e, n);
+        BigInteger decryptedText = cipherText.modPow(d, n);
+        System.out.println("Message: " + message);
+        System.out.println("Prime 1: " + p);
+        System.out.println("Prime 2: " + q);
+        System.out.println("Phi p1 * p2: " + phi);
+        System.out.println("p1 * p2: " + n);
+        System.out.println("Public key: " + e);
+        System.out.println("Private key: " + d);
+        System.out.println("Ciphertext: " + cipherText);
+        System.out.println("Decrypted message(number form): " + decryptedText);
+        //Convert BigInteger to byte array then to String
+        System.out.println("Decrypted message(string): " + new String(decryptedText.toByteArray()));
+    }
+}