Bael 5190: Verify Digital Signatures in Java article (#13439)

* #BAEL-5190: add keystore and certificate files

* #BAEL-5190: add keystore address

* #BAEL-5190: update hashing

* #BAEL-5190: delete main classes

* #BAEL-5190: move keystore files to test directory

* #BAEL-5190: rename to DigitalSignatureUtils

* #BAEL-5190: main source code

* #BAEL-5190: main test source

* #BAEL-5190: update for testing

* #BAEL-5190: update keystore type

* #BAEL-5190: remove p12 keystores

* #BAEL-5190: add jks keystores

---------

Co-authored-by: h_sharifi <h_sharifi@modernisc.com>

libraries-security/src/test/java/com/baeldung/digitalsignature/DigitalSignatureUnitTest.java

@@ -0,0 +1,76 @@
+package com.baeldung.digitalsignature;
+
+import org.junit.Test;
+
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.security.PrivateKey;
+import java.security.PublicKey;
+
+import static org.junit.Assert.assertTrue;
+
+public class DigitalSignatureUnitTest {
+
+    String messagePath = "src/test/resources/digitalsignature/message.txt";
+    String senderKeyStore = "src/test/resources/digitalsignature/sender_keystore.jks";
+    String receiverKeyStore = "src/test/resources/digitalsignature/receiver_keystore.jks";
+    String storeType = "JKS";
+    String senderAlias = "senderKeyPair";
+    String receiverAlias = "receiverKeyPair";
+    char[] password = "changeit".toCharArray();
+    String signingAlgorithm = "SHA256withRSA";
+    String hashingAlgorithm = "SHA-256";
+
+    @Test
+    public void givenMessageData_whenSignWithSignatureSigning_thenVerify() throws Exception {
+        PrivateKey privateKey = DigitalSignatureUtils.getPrivateKey(senderKeyStore, password, storeType, senderAlias);
+        byte[] messageBytes = Files.readAllBytes(Paths.get(messagePath));
+
+        byte[] digitalSignature = DigitalSignatureUtils.sign(messageBytes, signingAlgorithm, privateKey);
+
+        PublicKey publicKey = DigitalSignatureUtils.getPublicKey(receiverKeyStore, password, storeType, receiverAlias);
+        boolean isCorrect = DigitalSignatureUtils.verify(messageBytes, signingAlgorithm, publicKey, digitalSignature);
+
+        assertTrue(isCorrect);
+    }
+
+    @Test
+    public void givenMessageData_whenSignWithMessageDigestAndCipher_thenVerify() throws Exception {
+        PrivateKey privateKey = DigitalSignatureUtils.getPrivateKey(senderKeyStore, password, storeType, senderAlias);
+        byte[] messageBytes = Files.readAllBytes(Paths.get(messagePath));
+
+        byte[] encryptedMessageHash = DigitalSignatureUtils.signWithMessageDigestAndCipher(messageBytes, hashingAlgorithm, privateKey);
+
+        PublicKey publicKey = DigitalSignatureUtils.getPublicKey(receiverKeyStore, password, storeType, receiverAlias);
+        boolean isCorrect = DigitalSignatureUtils.verifyWithMessageDigestAndCipher(messageBytes, hashingAlgorithm, publicKey, encryptedMessageHash);
+
+        assertTrue(isCorrect);
+    }
+
+    @Test
+    public void givenMessageData_whenSignWithSignatureSigning_thenVerifyWithMessageDigestAndCipher() throws Exception {
+        PrivateKey privateKey = DigitalSignatureUtils.getPrivateKey(senderKeyStore, password, storeType, senderAlias);
+        byte[] messageBytes = Files.readAllBytes(Paths.get(messagePath));
+
+        byte[] digitalSignature = DigitalSignatureUtils.sign(messageBytes, signingAlgorithm, privateKey);
+
+        PublicKey publicKey = DigitalSignatureUtils.getPublicKey(receiverKeyStore, password, storeType, receiverAlias);
+        boolean isCorrect = DigitalSignatureUtils.verifyWithMessageDigestAndCipher(messageBytes, hashingAlgorithm, publicKey, digitalSignature);
+
+        assertTrue(isCorrect);
+    }
+
+    @Test
+    public void givenMessageData_whenSignWithMessageDigestAndCipher_thenVerifyWithSignature() throws Exception {
+        PrivateKey privateKey = DigitalSignatureUtils.getPrivateKey(senderKeyStore, password, storeType, senderAlias);
+        byte[] messageBytes = Files.readAllBytes(Paths.get(messagePath));
+
+        byte[] encryptedMessageHash = DigitalSignatureUtils.signWithMessageDigestAndCipher(messageBytes, hashingAlgorithm, privateKey);
+
+        PublicKey publicKey = DigitalSignatureUtils.getPublicKey(receiverKeyStore, password, storeType, receiverAlias);
+        boolean isCorrect = DigitalSignatureUtils.verify(messageBytes, signingAlgorithm, publicKey, encryptedMessageHash);
+
+        assertTrue(isCorrect);
+    }
+
+}

libraries-security/src/test/resources/digitalsignature/sender_certificate.cer

@@ -0,0 +1,17 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----