Added RSA

Author: souro1212

src/main/java/com/example/rsaservice/RsaBackendServiceApplication.java

@@ -0,0 +1,12 @@
+
+package com.example.rsaservice;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class RsaBackendServiceApplication {
+    public static void main(String[] args) {
+        SpringApplication.run(RsaBackendServiceApplication.class, args);
+    }
+}

src/main/java/com/example/rsaservice/util/RSAUtil.java

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+
+package com.example.rsaservice.util;
+
+import javax.crypto.Cipher;
+import java.security.*;
+import java.util.Base64;
+
+public class RSAUtil {
+    private static final String ALGORITHM = "RSA";
+    private static final String TRANSFORMATION = "RSA/ECB/OAEPWithSHA-1AndMGF1Padding";
+    private static KeyPair keyPair;
+
+    static {
+        try {
+            KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance(ALGORITHM);
+            keyPairGenerator.initialize(2048);
+            keyPair = keyPairGenerator.generateKeyPair();
+        } catch (Exception e) {
+            throw new RuntimeException("Error initializing RSA KeyPair", e);
+        }
+    }
+
+    public static String encrypt(String plaintext) throws Exception {
+        Cipher cipher = Cipher.getInstance(TRANSFORMATION);
+        cipher.init(Cipher.ENCRYPT_MODE, keyPair.getPublic());
+        byte[] encryptedBytes = cipher.doFinal(plaintext.getBytes());
+        return Base64.getEncoder().encodeToString(encryptedBytes);
+    }
+
+    public static String decrypt(String encryptedText) throws Exception {
+        Cipher cipher = Cipher.getInstance(TRANSFORMATION);
+        cipher.init(Cipher.DECRYPT_MODE, keyPair.getPrivate());
+        byte[] decryptedBytes = cipher.doFinal(Base64.getDecoder().decode(encryptedText));
+        return new String(decryptedBytes);
+    }
+}

src/main/resources/application.properties

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+
+server.port=8080