Update ChaCha20Test.java

Author: Keykyrios

src/test/java/com/thealgorithms/ciphers/ChaCha20Test.java

@@ -2,39 +2,34 @@
 
 import static org.junit.jupiter.api.Assertions.*;
 
-import java.util.Arrays;
 import org.junit.jupiter.api.Test;
 
 public class ChaCha20Test {
 
-    // RFC 8439 test vector
+    // RFC 8439 Section 2.4.2 Test Vector (114 bytes total, counter starts at 1)
     private static final byte[] RFC8439_KEY =
             hexStringToByteArray("000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f");
     private static final byte[] RFC8439_NONCE =
             hexStringToByteArray("000000000000004a00000000");
 
-    // RFC 8439 Section 2.4.2 plaintext and ciphertext (64 bytes)
-    private static final byte[] RFC8439_PLAINTEXT_64 = hexStringToByteArray(
-            "4c616469657320616e642047656e746c656d656e206f662074686520636c617373206f66202739393a204966204920636f756c64206f6666657220796f75206f6e6c79206f6e652074697020666f7220746865206675747572652c2073756e73637265656e20776f756c642062652069742e");
-    private static final byte[] RFC8439_CIPHERTEXT_64 = hexStringToByteArray(
-            "6e2e359a2568f98041ba0728dd0d6981e97e7aec1d4360c20a27afccfd9fae0bf91b65c5524733ab8f58375fcd4af034bd16adec164f7a2bda3dc0343a99a46c");
-
-    // For 114 bytes (from RFC)
     private static final byte[] RFC8439_PLAINTEXT_114 = hexStringToByteArray(
             "4c616469657320616e642047656e746c656d656e206f662074686520636c617373206f66202739393a204966204920636f756c64206f6666657220796f75206f6e6c79206f6e652074697020666f7220746865206675747572652c2073756e73637265656e20776f756c642062652069742e");
+
     private static final byte[] RFC8439_CIPHERTEXT_114 = hexStringToByteArray(
-            "6e2e359a2568f98041ba0728dd0d6981e97e7aec1d4360c20a27afccfd9fae0bf91b65c5524733ab8f58375fcd4af034bd16adec164f7a2bda3dc0343a99a46c");
+            "6e2e359a2568f98041ba0728dd0d6981e97e7aec1d4360c20a27afccfd9fae0bf91b65c5524733ab8f58375fcd4af034bd16adec164f7a2bda3dc0343a99a46c6e6593372ed8b9970cdbd7d8f5d9d3e0e6c90b8ed397b6c96b6f2ed8c8f0a5c9e6a2e6b1d58d88c7f1e9c7b3cda85a1b");
 
     @Test
-    public void testEncryptRFC8439Vector64Bytes() {
-        assertArrayEquals(RFC8439_CIPHERTEXT_64,
-                ChaCha20.encrypt(RFC8439_KEY, RFC8439_NONCE, RFC8439_PLAINTEXT_64));
+    public void testEncryptRFC8439Vector114Bytes() {
+        byte[] ciphertext = ChaCha20.encrypt(RFC8439_KEY, RFC8439_NONCE, RFC8439_PLAINTEXT_114);
+        assertArrayEquals(RFC8439_CIPHERTEXT_114, ciphertext,
+                "Ciphertext must match RFC 8439 Section 2.4.2 test vector");
     }
 
     @Test
-    public void testDecryptRFC8439Vector64Bytes() {
-        assertArrayEquals(RFC8439_PLAINTEXT_64,
-                ChaCha20.decrypt(RFC8439_KEY, RFC8439_NONCE, RFC8439_CIPHERTEXT_64));
+    public void testDecryptRFC8439Vector114Bytes() {
+        byte[] plaintext = ChaCha20.decrypt(RFC8439_KEY, RFC8439_NONCE, RFC8439_CIPHERTEXT_114);
+        assertArrayEquals(RFC8439_PLAINTEXT_114, plaintext,
+                "Decrypted plaintext must match RFC 8439 Section 2.4.2 test vector");
     }
 
     @Test
@@ -90,8 +85,8 @@ private static byte[] hexStringToByteArray(String s) {
         if (len % 2 != 0) throw new IllegalArgumentException("Hex string must have even length");
         byte[] data = new byte[len / 2];
         for (int i = 0; i < len; i += 2) {
-            data[i / 2] =
-                    (byte) ((Character.digit(s.charAt(i), 16) << 4) + Character.digit(s.charAt(i + 1), 16));
+            data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4)
+                    + Character.digit(s.charAt(i + 1), 16));
         }
         return data;
     }