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Bael 4485 (#10612)

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* BAEL-4485 RSA in Java

* BAEL-4485 RSA in Java

* BAEL-4485 RSA in Java

Co-authored-by: majewsk6 <krzysztof.majewski.km1@contractors.roche.com>
This commit is contained in:
Krzysztof Majewski 2021-03-31 22:52:31 +02:00 committed by GitHub
parent 34d4a4032d
commit 9706d7b6fd
1 changed files with 92 additions and 0 deletions
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core-java-modules/core-java-security-2/src/test/java/com/baeldung/rsa/RsaUnitTest.java Normal file
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package com.baeldung.cipher;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;
import javax.crypto.Cipher;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
public class RsaUnitTest {
@Test
public void givenRsaKeyPair_whenEncryptAndDecryptString_thenCompareResults() throws Exception {
KeyPairGenerator generator = KeyPairGenerator.getInstance("RSA");
generator.initialize(2048);
KeyPair pair = generator.generateKeyPair();
PrivateKey privateKey = pair.getPrivate();
PublicKey publicKey = pair.getPublic();
String secretMessage = "Baeldung secret message";
Cipher encryptCipher = Cipher.getInstance("RSA");
encryptCipher.init(Cipher.ENCRYPT_MODE, publicKey);
byte[] secretMessageBytes = secretMessage.getBytes(StandardCharsets.UTF_8);
byte[] encryptedMessageBytes = encryptCipher.doFinal(secretMessageBytes);
Cipher decryptCipher = Cipher.getInstance("RSA");
decryptCipher.init(Cipher.DECRYPT_MODE, privateKey);
byte[] decryptedMessageBytes = decryptCipher.doFinal(encryptedMessageBytes);
String decryptedMessage = new String(decryptedMessageBytes, StandardCharsets.UTF_8);
Assertions.assertEquals(secretMessage, decryptedMessage);
}
@Test
public void givenRsaKeyPair_whenEncryptAndDecryptFile_thenCompareResults() throws Exception {
KeyPairGenerator generator = KeyPairGenerator.getInstance("RSA");
generator.initialize(2048);
KeyPair pair = generator.generateKeyPair();
PrivateKey privateKey = pair.getPrivate();
PublicKey publicKey = pair.getPublic();
String originalContent = "some secret message";
Path tempFile = Files.createTempFile("temp", "txt");
writeString(tempFile, originalContent);
byte[] fileBytes = Files.readAllBytes(tempFile);
Cipher encryptCipher = Cipher.getInstance("RSA");
encryptCipher.init(Cipher.ENCRYPT_MODE, publicKey);
byte[] encryptedFileBytes = encryptCipher.doFinal(fileBytes);
try (FileOutputStream stream = new FileOutputStream(tempFile.toFile())) {
stream.write(encryptedFileBytes);
}
encryptedFileBytes = Files.readAllBytes(tempFile);
Cipher decryptCipher = Cipher.getInstance("RSA");
decryptCipher.init(Cipher.DECRYPT_MODE, privateKey);
byte[] decryptedFileBytes = decryptCipher.doFinal(encryptedFileBytes);
try (FileOutputStream stream = new FileOutputStream(tempFile.toFile())) {
stream.write(decryptedFileBytes);
}
String fileContent = readString(tempFile);
Assertions.assertEquals(originalContent, fileContent);
}
private void writeString(Path path, String content) throws Exception {
try (BufferedWriter writer = Files.newBufferedWriter(path)) {
writer.write(content);
}
}
private String readString(Path path) throws Exception {
StringBuilder resultStringBuilder = new StringBuilder();
try (BufferedReader br = new BufferedReader(new FileReader(path.toFile()))) {
String line;
while ((line = br.readLine()) != null) {
resultStringBuilder.append(line);
}
}
return resultStringBuilder.toString();
}
}