feat: load ECDSA key pairs with pem-formatted text

Author: zihluwang

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

@@ -0,0 +1,100 @@
+/*
+ * Copyright (C) 2024-2024 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.onixbyte.security;
+
+import com.onixbyte.security.exception.KeyLoadingException;
+import lombok.extern.slf4j.Slf4j;
+
+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.PKCS8EncodedKeySpec;
+import java.security.spec.X509EncodedKeySpec;
+import java.util.Base64;
+
+/**
+ * KeyLoader can load key pairs from PEM formated content.
+ *
+ * @author zihluwang
+ * @version 1.6.0
+ * @since 1.6.0
+ */
+@Slf4j
+public class KeyLoader {
+
+    /**
+     * Private constructor prevents from being initialised.
+     */
+    private KeyLoader() {
+    }
+
+    /**
+     * Load ECDSA private key from pem-formatted key text.
+     *
+     * @param pemKeyText pem-formatted key text
+     * @return loaded private key
+     * @throws KeyLoadingException if the generated key is not a {@link ECPrivateKey} instance, or EC Key Factory is
+     *                             not loaded, or key spec is invalid
+     */
+    public ECPrivateKey loadEcdsaPrivateKey(String pemKeyText) {
+        try {
+            var decodedKeyString = Base64.getDecoder().decode(pemKeyText);
+            var keySpec = new PKCS8EncodedKeySpec(decodedKeyString);
+            var keyFactory = KeyFactory.getInstance("EC");
+            var _key = keyFactory.generatePrivate(keySpec);
+            if (_key instanceof ECPrivateKey privateKey) {
+                return privateKey;
+            } else {
+                throw new KeyLoadingException("Unable to load private key from pem-formatted key text.");
+            }
+        } catch (NoSuchAlgorithmException e) {
+            throw new KeyLoadingException("Cannot get EC Key Factory.", e);
+        } catch (InvalidKeySpecException e) {
+            throw new KeyLoadingException("Key spec is invalid.", e);
+        }
+    }
+
+    /**
+     * Load ECDSA public key from pem-formatted key text.
+     *
+     * @param pemKeyText pem-formatted key text
+     * @return loaded private key
+     * @throws KeyLoadingException if the generated key is not a {@link ECPrivateKey} instance, or EC Key Factory is
+     *                             not loaded, or key spec is invalid
+     */
+    public ECPublicKey loadEcdsaPublicKey(String pemKeyText) {
+        try {
+            var keyBytes = Base64.getDecoder().decode(pemKeyText);
+            var spec = new X509EncodedKeySpec(keyBytes);
+            var keyFactory = KeyFactory.getInstance("EC");
+            var key = keyFactory.generatePublic(spec);
+            if (key instanceof ECPublicKey publicKey) {
+                return publicKey;
+            } else {
+                throw new KeyLoadingException("Unable to load private key from pem-formatted key text.");
+            }
+        } catch (NoSuchAlgorithmException e) {
+            throw new KeyLoadingException("Cannot get EC Key Factory.", e);
+        } catch (InvalidKeySpecException e) {
+            throw new KeyLoadingException("Key spec is invalid.", e);
+        }
+    }
+
+}

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

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package com.onixbyte.keypairloader.exception;
+package com.onixbyte.security.exception;
 
 public class KeyLoadingException extends RuntimeException {
 

key-pair-loader/src/main/java/com/onixbyte/keypairloader/exception/KeyLoadingException.java renamed to key-pair-loader/src/main/java/com/onixbyte/security/exception/KeyLoadingException.java

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package com.onixbyte.keypairloader;
+package com.onixbyte.security;
 
 import org.junit.jupiter.api.Test;