Merge pull request #68 from onixbyte/feature/key-loader

feat: import key loading method

key-pair-loader/src/main/java/com/onixbyte/security/KeyLoader.java

@@ -17,8 +17,14 @@
 
 package com.onixbyte.security;
 
+import com.onixbyte.security.exception.KeyLoadingException;
+
+import java.security.KeyFactory;
 import java.security.PrivateKey;
 import java.security.PublicKey;
+import java.security.interfaces.ECPublicKey;
+import java.security.interfaces.RSAPublicKey;
+import java.security.spec.KeySpec;
 
 /**
  * The {@code KeyLoader} class provides utility methods for loading keys pairs from PEM-formatted
@@ -49,6 +55,41 @@ public interface KeyLoader {
      */
     PublicKey loadPublicKey(String pemKeyText);
 
+    /**
+     * Loads an RSA public key using the provided modulus and exponent.
+     * <p>
+     * This default implementation throws a {@link KeyLoadingException} to signify that this key loader does not support
+     * loading an RSA public key. Implementing classes are expected to override this method to supply their own
+     * loading logic.
+     *
+     * @param modulus  the modulus value of the RSA public key, usually represented in hexadecimal or Base64
+     *                 string format
+     * @param exponent the public exponent value of the RSA public key, usually represented in hexadecimal or Base64
+     *                 string format
+     * @return the loaded {@link RSAPublicKey} instance
+     * @throws KeyLoadingException if loading is not supported or fails
+     */
+    default RSAPublicKey loadPublicKey(String modulus, String exponent) {
+        throw new KeyLoadingException("This key loader does not support loading an RSA public key.");
+    }
+
+    /**
+     * Loads an EC public key using the provided x and y coordinates together with the curve name.
+     * <p>
+     * This default implementation throws a {@link KeyLoadingException} to signify that this key loader does not support
+     * loading an EC public key. Implementing classes are expected to override this method to supply their own
+     * loading logic.
+     *
+     * @param xHex      the hexadecimal string representing the x coordinate of the EC point
+     * @param yHex      the hexadecimal string representing the y coordinate of the EC point
+     * @param curveName the name of the elliptic curve
+     * @return the loaded {@link ECPublicKey} instance
+     * @throws KeyLoadingException if loading is not supported or fails
+     */
+    default ECPublicKey loadPublicKey(String xHex, String yHex, String curveName) {
+        throw new KeyLoadingException("This key loader does not support loading an EC public key.");
+    }
+
     /**
      * Retrieves the raw content of a PEM formatted key by removing unnecessary headers, footers,
      * and new line characters.

key-pair-loader/src/main/java/com/onixbyte/security/impl/ECKeyLoader.java

@@ -20,14 +20,16 @@ package com.onixbyte.security.impl;
 import com.onixbyte.security.KeyLoader;
 import com.onixbyte.security.exception.KeyLoadingException;
 
+import java.math.BigInteger;
+import java.security.AlgorithmParameters;
 import java.security.KeyFactory;
 import java.security.NoSuchAlgorithmException;
 import java.security.interfaces.ECPrivateKey;
 import java.security.interfaces.ECPublicKey;
-import java.security.spec.InvalidKeySpecException;
+import java.security.spec.*;
-import java.security.spec.PKCS8EncodedKeySpec;
-import java.security.spec.X509EncodedKeySpec;
 import java.util.Base64;
+import java.util.HashSet;
+import java.util.Set;
 
 /**
  * Key pair loader for loading key pairs for ECDSA-based algorithms.
@@ -53,16 +55,23 @@ import java.util.Base64;
  * @version 2.0.0
  * @since 2.0.0
  */
-public class EcKeyLoader implements KeyLoader {
+public class ECKeyLoader implements KeyLoader {
 
     private final KeyFactory keyFactory;
 
     private final Base64.Decoder decoder;
 
+    /**
+     * Supported curves.
+     */
+    public static final Set<String> SUPPORTED_CURVES = new HashSet<>(Set.of(
+            "secp256r1", "secp384r1", "secp521r1", "secp224r1"
+    ));
+
     /**
      * Initialise a key loader for EC-based algorithms.
      */
-    public EcKeyLoader() {
+    public ECKeyLoader() {
         try {
             this.keyFactory = KeyFactory.getInstance("EC");
             this.decoder = Base64.getDecoder();
@@ -122,4 +131,55 @@ public class EcKeyLoader implements KeyLoader {
         }
     }
 
+    /**
+     * Loads an EC public key from the given hexadecimal x and y coordinates alongside the curve name.
+     * <p>
+     * This method converts the hexadecimal string representations of the EC point coordinates into {@link BigInteger}
+     * instances, then constructs an {@link ECPoint} and retrieves the corresponding {@link ECParameterSpec} for the
+     * named curve. Subsequently, it utilises the {@link KeyFactory} to generate an {@link ECPublicKey}.
+     * <p>
+     * Only curves listed in {@link #SUPPORTED_CURVES} are supported. Should the specified curve name be unsupported,
+     * or if key construction fails due to invalid parameters or unsupported algorithms, a {@link KeyLoadingException}
+     * will be thrown.
+     *
+     * @param xHex      the hexadecimal string representing the x-coordinate of the EC point
+     * @param yHex      the hexadecimal string representing the y-coordinate of the EC point
+     * @param curveName the name of the elliptic curve
+     * @return the {@link ECPublicKey} generated from the specified coordinates and curve
+     * @throws KeyLoadingException if the curve is unsupported or key generation fails
+     */
+    @Override
+    public ECPublicKey loadPublicKey(String xHex, String yHex, String curveName) {
+        if (!SUPPORTED_CURVES.contains(curveName)) {
+            throw new KeyLoadingException("Given curve is not supported yet.");
+        }
+
+        try {
+            // Convert hex string coordinates to BigInteger
+            var x = new BigInteger(xHex, 16);
+            var y = new BigInteger(yHex, 16);
+
+            // Create ECPoint with (x, y)
+            var ecPoint = new ECPoint(x, y);
+
+            // Get EC parameter spec for the named curve
+            var parameters = AlgorithmParameters.getInstance("EC");
+            parameters.init(new ECGenParameterSpec(curveName));
+            var ecParameterSpec = parameters.getParameterSpec(ECParameterSpec.class);
+
+            // Create ECPublicKeySpec with point and curve params
+            var pubSpec = new ECPublicKeySpec(ecPoint, ecParameterSpec);
+
+            // Generate public key using KeyFactory
+            var publicKey = keyFactory.generatePublic(pubSpec);
+
+            if (publicKey instanceof ECPublicKey ecPublicKey) {
+                return ecPublicKey;
+            } else {
+                throw new KeyLoadingException("Cannot load EC public key with given x, y and curve name.");
+            }
+        } catch (NoSuchAlgorithmException | InvalidParameterSpecException | InvalidKeySpecException e) {
+            throw new KeyLoadingException("Cannot load EC public key with given x, y and curve name.", e);
+        }
+    }
 }

key-pair-loader/src/main/java/com/onixbyte/security/impl/RSAKeyLoader.java

@@ -20,13 +20,12 @@ package com.onixbyte.security.impl;
 import com.onixbyte.security.KeyLoader;
 import com.onixbyte.security.exception.KeyLoadingException;
 
+import java.math.BigInteger;
 import java.security.KeyFactory;
 import java.security.NoSuchAlgorithmException;
 import java.security.interfaces.RSAPrivateKey;
 import java.security.interfaces.RSAPublicKey;
-import java.security.spec.InvalidKeySpecException;
+import java.security.spec.*;
-import java.security.spec.PKCS8EncodedKeySpec;
-import java.security.spec.X509EncodedKeySpec;
 import java.util.Base64;
 
 /**
@@ -44,9 +43,12 @@ import java.util.Base64;
  * @see KeyLoader
  * @see KeyLoadingException
  */
-public class RsaKeyLoader implements KeyLoader {
+public class RSAKeyLoader implements KeyLoader {
 
     private final Base64.Decoder decoder;
+
+    private final Base64.Decoder urlDecoder;
+
     private final KeyFactory keyFactory;
 
     /**
@@ -55,9 +57,10 @@ public class RsaKeyLoader implements KeyLoader {
      * This constructor initialises the Base64 decoder and the RSA {@link KeyFactory}. It may throw
      * a {@link KeyLoadingException} if the RSA algorithm is not available.
      */
-    public RsaKeyLoader() {
+    public RSAKeyLoader() {
         try {
             this.decoder = Base64.getDecoder();
+            this.urlDecoder = Base64.getUrlDecoder();
             this.keyFactory = KeyFactory.getInstance("RSA");
         } catch (NoSuchAlgorithmException e) {
             throw new KeyLoadingException(e);
@@ -133,4 +136,31 @@ public class RsaKeyLoader implements KeyLoader {
             throw new KeyLoadingException("Key spec is invalid.", e);
         }
     }
+
+    /**
+     * Get the public key with given modulus and public exponent.
+     *
+     * @param modulus  the modulus
+     * @param exponent the public exponent
+     * @return generated public key object from the provided key specification
+     * @see KeyFactory#getInstance(String)
+     * @see KeyFactory#generatePublic(KeySpec)
+     */
+    @Override
+    public RSAPublicKey loadPublicKey(String modulus, String exponent) {
+        try {
+            var _modulus = new BigInteger(1, urlDecoder.decode(modulus));
+            var _exponent = new BigInteger(1, urlDecoder.decode(exponent));
+
+            var keySpec = new RSAPublicKeySpec(_modulus, _exponent);
+            var kf = KeyFactory.getInstance("RSA");
+            if (kf.generatePublic(keySpec) instanceof RSAPublicKey rsaPublicKey) {
+                return rsaPublicKey;
+            } else {
+                throw new KeyLoadingException("Cannot generate RSA public key with given modulus and exponent.");
+            }
+        } catch (NoSuchAlgorithmException | InvalidKeySpecException e) {
+            throw new KeyLoadingException("Cannot generate RSA public key with given modulus and exponent.", e);
+        }
+    }
 }

simple-jwt-authzero/src/main/java/com/onixbyte/simplejwt/authzero/AuthzeroTokenResolver.java

@@ -19,8 +19,7 @@ package com.onixbyte.simplejwt.authzero;
 
 import com.onixbyte.devkit.utils.Base64Util;
 import com.onixbyte.guid.GuidCreator;
-import com.onixbyte.security.KeyLoader;
+import com.onixbyte.security.impl.ECKeyLoader;
-import com.onixbyte.security.impl.EcKeyLoader;
 import com.onixbyte.simplejwt.TokenPayload;
 import com.onixbyte.simplejwt.TokenResolver;
 import com.onixbyte.simplejwt.annotations.ExcludeFromPayload;
@@ -43,7 +42,6 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.lang.reflect.InvocationTargetException;
-import java.security.NoSuchAlgorithmException;
 import java.security.interfaces.ECPrivateKey;
 import java.security.interfaces.ECPublicKey;
 import java.time.Duration;
@@ -179,7 +177,7 @@ public class AuthzeroTokenResolver implements TokenResolver<DecodedJWT> {
          * @return the builder instance
          */
         public Builder keyPair(String publicKey, String privateKey) {
-            var keyLoader = new EcKeyLoader();
+            var keyLoader = new ECKeyLoader();
             this.publicKey = keyLoader.loadPublicKey(publicKey);
             this.privateKey = keyLoader.loadPrivateKey(privateKey);
             return this;