Update JWTUtils.java

src/main/java/org/sasanlabs/service/vulnerability/jwt/bean/JWTUtils.java

@@ -18,8 +18,13 @@
 import org.sasanlabs.service.exception.ExceptionStatusCodeEnum;
 import org.sasanlabs.service.exception.ServiceApplicationException;
 
-/** @author KSASAN preetkaran20@gmail.com */
-public class JWTUtils {
+/** Utility class for JWT operations. */
+public final class JWTUtils {
+
+    // Utility class → private constructor to prevent instantiation
+    private JWTUtils() {
+        throw new IllegalStateException("Utility class");
+    }
 
     public static final char JWT_TOKEN_PERIOD_CHARACTER = '.';
 
@@ -37,7 +42,7 @@ public class JWTUtils {
     public static final String JWT_EC_ALGORITHM_IDENTIFIER = "EC";
     public static final String JWT_OCTET_ALGORITHM_IDENTIFIER = "ED";
     public static final String JWT_HMAC_SHA_256_ALGORITHM = "HS256";
-    // TODO need to make it better.
+
     public static final String HS256_TOKEN_TO_BE_SIGNED =
             "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9."
                     + "eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ";
@@ -50,17 +55,10 @@ public class JWTUtils {
             "eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG"
                     + "4gRG9lIiwiYWRtaW4iOnRydWUsImlhdCI6MTUxNjIzOTAyMn0";
 
+    // Location of keys
     public static final String KEYS_LOCATION = "static/templates/JWTVulnerability/keys/";
 
-    /**
-     * This is the Begining and Ending token of Public and Private Keys encoded with PKCS#8
-     * encoding. In case you find PEM file not having these tokens and instead have -----BEGIN RSA
-     * PRIVATE KEY----- or -----BEGIN RSA PUBLIC KEY----- then those are encoded by old format. To
-     * Generate new Keys please use following <a
-     * href="https://en.wikibooks.org/wiki/Cryptography/Generate_a_keypair_using_OpenSSL">link</a>
-     */
     public static final String BEGIN_PRIVATE_KEY_TOKEN = "-----BEGIN PRIVATE KEY-----";
-
     public static final String END_PRIVATE_KEY_TOKEN = "-----END PRIVATE KEY-----";
     public static final String BEGIN_PUBLIC_KEY_TOKEN = "-----BEGIN PUBLIC KEY-----";
     public static final String END_PUBLIC_KEY_TOKEN = "-----END PUBLIC KEY-----";
@@ -76,54 +74,25 @@ public static String getString(byte[] tokenBytes) throws UnsupportedEncodingExce
     public static final Map<String, String> JWT_HMAC_ALGO_TO_JAVA_ALGORITHM_MAPPING =
             createJWTHmacAlgoToJavaAlgoMapping();
 
-    static Map<String, String> createJWTHmacAlgoToJavaAlgoMapping() {
-        Map<String, String> jwtAlgoToJavaAlgoMapping = new HashMap<String, String>();
+    private static Map<String, String> createJWTHmacAlgoToJavaAlgoMapping() {
+        Map<String, String> jwtAlgoToJavaAlgoMapping = new HashMap<>();
         jwtAlgoToJavaAlgoMapping.put(JWT_HMAC_SHA_256_ALGORITHM, "HmacSHA256");
         jwtAlgoToJavaAlgoMapping.put("HS384", "HmacSHA384");
         jwtAlgoToJavaAlgoMapping.put("HS512", "HmacSHA512");
         return jwtAlgoToJavaAlgoMapping;
     }
 
-    /**
-     * we are using <a href="https://en.wikipedia.org/wiki/Base64#URL_applications">base64 Url Safe
-     * encoding</a>. because of JWT specifications <br>
-     * Also we are removing the padding as per <a
-     * href="https://www.rfc-editor.org/rfc/rfc7515.txt">RFC 7515</a> padding is not there in JWT.
-     *
-     * @param token
-     * @return
-     * @throws UnsupportedEncodingException
-     */
     public static String getBase64UrlSafeWithoutPaddingEncodedString(String token)
             throws UnsupportedEncodingException {
-        return JWTUtils.getBase64UrlSafeWithoutPaddingEncodedString(getBytes(token));
+        return getBase64UrlSafeWithoutPaddingEncodedString(getBytes(token));
     }
 
-    /**
-     * we are using <a href="https://en.wikipedia.org/wiki/Base64#URL_applications">base64 Url Safe
-     * encoding</a>. because of JWT specifications <br>
-     * Also we are removing the padding as per <a
-     * href="https://www.rfc-editor.org/rfc/rfc7515.txt">RFC 7515</a> padding is not there in JWT.
-     *
-     * @param token
-     * @return
-     * @throws UnsupportedEncodingException
-     */
     public static String getBase64UrlSafeWithoutPaddingEncodedString(byte[] token)
             throws UnsupportedEncodingException {
-        return JWTUtils.getString(Base64.getUrlEncoder().encode(token))
+        return getString(Base64.getUrlEncoder().encode(token))
                 .replaceAll(BASE64_PADDING_CHARACTER_REGEX, "");
     }
 
-    /**
-     * Utility method for reading the PEM file and building RSAPrivateKey from it. Note: This method
-     * assumes that PEM file contains PKCS#8 encoded Key format please check the format.
-     *
-     * @param pemFile InputStream of PEM file containing RSA Private Key
-     * @return RSAPrivateKey by reading PEM file containing the RSA Private Key.
-     * @throws JWTException if unable to read the provided file path or key specification is
-     *     incorrect etc.
-     */
     public static RSAPrivateKey getRSAPrivateKeyFromProvidedPEMFilePath(InputStream pemFile)
             throws ServiceApplicationException {
         try {
@@ -138,15 +107,6 @@ public static RSAPrivateKey getRSAPrivateKeyFromProvidedPEMFilePath(InputStream
         }
     }
 
-    /**
-     * Utility method for reading the PEM file and building RSAPublicKey from it. Note: This method
-     * assumes that PEM file contains PKCS#8 encoded Key format please check the format.
-     *
-     * @param pemFile InputStream of PEM file containing RSA Public Key.
-     * @return RSAPublicKey by reading PEM file containing the RSA Private Key.
-     * @throws JWTException if unable to read the provided file path or key specification is
-     *     incorrect etc.
-     */
     public static RSAPublicKey getRSAPublicKeyFromProvidedPEMFilePath(InputStream pemFile)
             throws ServiceApplicationException {
         try {
@@ -161,33 +121,11 @@ public static RSAPublicKey getRSAPublicKeyFromProvidedPEMFilePath(InputStream pe
         }
     }
 
-    /**
-     * Checks if the provided tokens i.e. {@param beginToken} or {@param endToken} are present in
-     * the provided {@param contents}.
-     *
-     * @param contents
-     * @param beginToken
-     * @param endToken
-     * @return true if provided token params are present in contents else false.
-     */
     private static boolean containsSection(String contents, String beginToken, String endToken) {
-        int idxToken;
-        if ((idxToken = contents.indexOf(beginToken)) == -1
-                || contents.indexOf(endToken) < idxToken) {
-            return false;
-        }
-        return true;
+        int idxToken = contents.indexOf(beginToken);
+        return idxToken != -1 && contents.indexOf(endToken) > idxToken;
     }
 
-    /**
-     * Converts PEM to DER format i.e. removes the Begin and End tokens and decode the base64
-     * encoded certificate.
-     *
-     * @param pem
-     * @param beginDelimiter
-     * @param endDelimiter
-     * @return DER format Key
-     */
     private static byte[] parseDERFromPEM(String pem, String beginDelimiter, String endDelimiter) {
         if (!containsSection(pem, beginDelimiter, endDelimiter)) {
             return new byte[0];