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rsa-encryption-decryption/readme.rst

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+You can read tutorial https://www.jeejava.com/encryption-and-decryption-using-rsa-in-java/

rsa-encryption-decryption/src/main/java/com/jeejava/rsa/RSAConstants.java

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+package com.jeejava.rsa;
+
+public final class RSAConstants {
+
+ private RSAConstants() {
+ }
+
+ public static final String ALGORITHM = "RSA";
+ public static final int ALGORITHM_BITS = 2048;
+}

rsa-encryption-decryption/src/main/java/com/jeejava/rsa/RSAEncryptDecrypt.java

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+package com.jeejava.rsa;
+
+import java.security.Key;
+
+import javax.crypto.Cipher;
+
+public class RSAEncryptDecrypt {
+
+ public static byte[] encrypt(String original, Key privateKey) {
+ if (original != null && privateKey != null) {
+ byte[] bs = original.getBytes();
+ byte[] encData = convert(bs, privateKey, Cipher.ENCRYPT_MODE);
+ return encData;
+ }
+ return null;
+ }
+
+ public static byte[] decrypt(byte[] encrypted, Key publicKey) {
+ if (encrypted != null && publicKey != null) {
+ byte[] decData = convert(encrypted, publicKey, Cipher.DECRYPT_MODE);
+ return decData;
+ }
+ return null;
+ }
+
+ private static byte[] convert(byte[] data, Key key, int mode) {
+ try {
+ Cipher cipher = Cipher.getInstance(RSAConstants.ALGORITHM);
+ cipher.init(mode, key);
+ byte[] newData = cipher.doFinal(data);
+ return newData;
+ } catch (Exception e) {
+ e.printStackTrace();
+ }
+ return null;
+ }
+
+}

rsa-encryption-decryption/src/main/java/com/jeejava/rsa/RSAKeyPair.java

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+package com.jeejava.rsa;
+
+import java.security.KeyPair;
+import java.security.KeyPairGenerator;
+
+public class RSAKeyPair {
+
+ public static KeyPair keyPairRSA() {
+ KeyPairGenerator generator = null;
+ try {
+ generator = KeyPairGenerator.getInstance(RSAConstants.ALGORITHM);
+ } catch (Exception e) {
+ e.printStackTrace();
+ }
+ if (generator != null) {
+ generator.initialize(RSAConstants.ALGORITHM_BITS);
+ KeyPair keyPair = generator.genKeyPair();
+ return keyPair;
+ }
+ return null;
+ }
+
+}

rsa-encryption-decryption/src/main/java/com/jeejava/rsa/RSATest.java

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+package com.jeejava.rsa;
+
+import java.security.Key;
+import java.security.KeyPair;
+import java.util.Arrays;
+
+public class RSATest {
+
+ public static void main(String[] args) {
+ String password = "password";
+ KeyPair keyPair = RSAKeyPair.keyPairRSA();
+ Key publicKey = keyPair.getPublic();
+ Key privateKey = keyPair.getPrivate();
+
+ System.out.println("Encrypt Start");
+ System.out.println("Original: " + password);
+ byte[] encrypted = RSAEncryptDecrypt.encrypt(password, privateKey);
+ System.out.println("Encrypted: " + new String(encrypted));
+ System.out.println("Encrypt End");
+
+ System.out.println();
+
+ System.out.println("Decrypt Start");
+ byte[] decrypted = RSAEncryptDecrypt.decrypt(encrypted, publicKey);
+ System.out.println("Decrypted: " + new String(decrypted));
+ System.out.println("Decrypted matches Original: " + Arrays.equals(decrypted, password.getBytes()));
+ System.out.println("Decrypt End");
+ }
+
+}