feat: load RSA key pair from pem-formatted key text

Author: siujamo

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

@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2024-2025 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.impl;
+
+import com.onixbyte.security.KeyLoader;
+import com.onixbyte.security.exception.KeyLoadingException;
+
+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.PKCS8EncodedKeySpec;
+import java.security.spec.X509EncodedKeySpec;
+import java.util.Base64;
+
+public class RsaKeyLoader implements KeyLoader {
+
+    private final Base64.Decoder decoder;
+    private final KeyFactory keyFactory;
+
+    public RsaKeyLoader() {
+        try {
+            this.decoder = Base64.getDecoder();
+            this.keyFactory = KeyFactory.getInstance("RSA");
+        } catch (NoSuchAlgorithmException e) {
+            throw new KeyLoadingException(e);
+        }
+    }
+
+    @Override
+    public RSAPrivateKey loadPrivateKey(String pemKeyText) {
+        // Extract the raw key content
+        var rawKeyContent = getRawContent(pemKeyText);
+
+        // Decode the Base64-encoded content
+        var keyBytes = decoder.decode(rawKeyContent);
+
+        // Create a PKCS8EncodedKeySpec from the decoded bytes
+        var keySpec = new PKCS8EncodedKeySpec(keyBytes);
+
+        try {
+            // Get an RSA KeyFactory and generate the private key
+            var _key = keyFactory.generatePrivate(keySpec);
+            if (_key instanceof RSAPrivateKey key) {
+                return key;
+            } else {
+                throw new KeyLoadingException("Unable to load private key from pem-formatted key text.");
+            }
+        } catch (InvalidKeySpecException e) {
+            throw new KeyLoadingException("Key spec is invalid.", e);
+        }
+    }
+
+    @Override
+    public RSAPublicKey loadPublicKey(String pemKeyText) {
+        // Extract the raw key content
+        var rawKeyContent = getRawContent(pemKeyText);
+
+        // Decode the Base64-encoded content
+        var keyBytes = decoder.decode(rawKeyContent);
+
+        // Create an X509EncodedKeySpec from the decoded bytes
+        var keySpec = new X509EncodedKeySpec(keyBytes);
+
+        // Get an RSA KeyFactory and generate the public key
+        try {
+            var _key = keyFactory.generatePublic(keySpec);
+            if (_key instanceof RSAPublicKey key) {
+                return key;
+            } else {
+                throw new KeyLoadingException("Unable to load public key from pem-formatted key text.");
+            }
+        } catch (InvalidKeySpecException e) {
+            throw new KeyLoadingException("Key spec is invalid.", e);
+        }
+    }
+}

key-pair-loader/src/test/java/com/onixbyte/security/KeyPairLoaderTest.java

@@ -0,0 +1,28 @@
+-----BEGIN PRIVATE KEY-----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+-----END PRIVATE KEY-----

key-pair-loader/src/test/resources/ec_private_key_pkcs8.pem

@@ -0,0 +1,9 @@
+-----BEGIN PUBLIC KEY-----
+MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA+FSBWCRTALNeYyd1dyIn
+B3e7CNkyBak2TBONM5TpVQJTyi2Zk0L2RSzYGlAALLz4uYtQ0dssMCugJQX58FZ8
+75g1wuZihzs+KMTkFQOjZadslWkDM4nZn2DUpDLXL/+B0T7GrXOyvzOZeqQj9tA1
+UY5IpAXSMvHvcPsegayBaeUPD2XP19gRjQFDDGAAnXmB+UfwNAsapDQ9d3rHOIJM
+pzDq72a2Rhws+dbrH0gqsg1lsLDfhhui2FomuBpDZUtHq0Jz/IEvd3X45XvegSH8
+t8+yL/pFK3+YpDVtj/IzMSwL+izvnXFALvZOO+8CABeyKuSjLh/6LbAzrvoftql5
+gQIDAQAB
+-----END PUBLIC KEY-----