java_file_encryption.tar.gz_it

import junit.framework.Test; import junit.framework.TestCase; import junit.framework.TestSuite; import org.apache.commons.codec.binary.Hex; import javax.crypto.Cipher; import javax.crypto.KeyGenerator; import javax.crypto.SecretKey; import javax.crypto.spec.SecretKeySpec; import java.io.*; import java.security.interfaces.RSAPrivateKey; import java.security.interfaces.RSAPublicKey; import java.util.HashMap; import java.util.Map; public class FileEncryptionTest extends TestCase { protected static String FOLDER_PATH = "c:/temp/"; /** * Create the test case * * @param testName name of the test case */ public FileEncryptionTest(String testName) { super(testName); } /** * @return the suite of tests being tested */ public static Test suite() { return new TestSuite(FileEncryptionTest.class); } public void testEncryptLargeFile() throws Exception { // Generate public and private keys RSAKeyManager keyMan = new RSAKeyManager(); keyMan.generateKeyPair(); RSAPublicKey publicKey = keyMan.getPublicKey(); RSAPrivateKey privateKey = keyMan.getPrivateKey(); String modulus = keyMan.getModulusAsHex(); String exponent = keyMan.getPrivateExponentAsHex(); // Store module and exponent in a secured file. Pass modulus to the client // AES to encrypt the log file long startTime = System.currentTimeMillis(); String logFile = readLogFile(FOLDER_PATH + "sample.txt"); AESUtils aesUtils = new AESUtils(); byte[] secretKey = aesUtils.generateSecretKey(); String hexSecretKey = aesUtils.getSecretyKey(); String encryptedHexContent = new String(Hex.encodeHex(aesUtils.encrypt(logFile))); System.out.println("Encrypted content in hex: " + encryptedHexContent); long endTime = System.currentTimeMillis(); System.out.println("Encryption time: " + (endTime - startTime) / 1000); // Should save the hexSecretyKey and encrypted hex content in text file RSAEncryptor encryptor = new RSAEncryptor(modulus); String encryptedHexSecretKey = encryptor.encryptString(hexSecretKey); // Store encryptedHexSecretKey and encryptedHexSecretKey in files // On our side startTime = System.currentTimeMillis(); // Decrypt the RSA encrypted secrety key using our Private Key RSADecryptor decryptor = new RSADecryptor(modulus, exponent); hexSecretKey = decryptor.decryptText(encryptedHexSecretKey); // Un-hex the hex secrety key secretKey = Hex.decodeHex(hexSecretKey.toCharArray()); // Now we have the original secret key, decode the content // Un-hex the content byte[] encryptedContent = Hex.decodeHex(encryptedHexContent.toCharArray()); aesUtils.setSecretKey(secretKey); byte[] originalContent = aesUtils.decrypt(encryptedContent); System.out.println("Original content: " + new String(originalContent)); endTime = System.currentTimeMillis(); System.out.println("Decryption time: " + (endTime - startTime) / 1000); } public void testAES() throws Exception { String message = readLogFile(FOLDER_PATH + "sample.txt"); // Get the KeyGenerator KeyGenerator kgen = KeyGenerator.getInstance("AES"); kgen.init(128); // 192 and 256 bits may not be available // Generate the secret key specs. SecretKey skey = kgen.generateKey(); byte[] raw = skey.getEncoded(); SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES"); // Instantiate the cipher Cipher cipher = Cipher.getInstance("AES"); cipher.init(Cipher.ENCRYPT_MODE, skeySpec); long startTime = System.currentTimeMillis(); byte[] encrypted = cipher.doFinal(message.getBytes()); System.out.println("encrypted string: " + asHex(encrypted)); long endTime = System.currentTimeMillis(); System.out.println("Encryption time: " + (endTime - startTime) / 1000); startTime = System.currentTimeMillis(); cipher.init(Cipher.DECRYPT_MODE, skeySpec); byte[] original = cipher.doFinal(encrypted); String originalString = new String(original); System.out.println("Original string: " + originalString + " " + asHex(original)); endTime = System.currentTimeMillis(); System.out.println("Decryption time: " + (endTime - startTime) / 1000); } /** * Turns array of bytes into string * * @param buf Array of bytes to convert to hex string * @return Generated hex string */ public String asHex(byte buf[]) { return new String(Hex.encodeHex(buf)); } public void testRSA() throws Exception { Map<String, String> privateKeys; String cleartext = "Session Key"; int keySize = 1024; privateKeys = new HashMap<String, String>(); String modulus = generateKeys(privateKeys, keySize); System.out.println("Generated a key pair with a modulus of " + modulus); // the client will use the modulus to encrypt their password String encryptedText = encrypt(modulus, cleartext); System.out.println("Encrypted the text : " + encryptedText); // the server will receive the encrypted text and modulus to perform its decryption String decryptedText = decrypt(modulus, encryptedText, privateKeys); System.out.println("Decrypted as " + decryptedText); } private String decrypt(String modulus, String encryptedText, Map<String, String> privateKeys) throws RSAException { String exponent = privateKeys.get(modulus); RSADecryptor server = new RSADecryptor(modulus, exponent); return server.decryptText(encryptedText); } private String encrypt(String modulus, String clearText) throws RSAException { RSAEncryptor client = new RSAEncryptor(modulus); return client.encryptString(clearText); } private String generateKeys(Map<String, String> privateKeys, int keySize) throws RSAException { RSAKeyManager keyMan = new RSAKeyManager(keySize); keyMan.generateKeyPair(); String modulus = keyMan.getModulusAsHex(); String exponent = keyMan.getPrivateExponentAsHex(); // You will need to store the private key somewhere in order to // re-use it for the decryption. A resident memory cache is a great // option, if possible, to ensure that the private exponent is kept secret // (as opposed to a database) privateKeys.put(modulus, exponent); return modulus; } private String readLogFile(String filePath) throws Exception { File aFile = new File(filePath); //...checks on aFile are elided StringBuffer contents = new StringBuffer(); //declared here only to make visible to finally clause BufferedReader input = null; try { input = new BufferedReader(new FileReader(aFile)); String line = null; //not declared within while loop /* * readLine is a bit quirky : * it returns the content of a line MINUS the newline. * it returns null only for the END of the stream. * it returns an empty String if two newlines appear in a row. */ while ((line = input.readLine()) != null) { contents.append(line); contents.append(System.getProperty("line.separator")); } } catch (FileNotFoundException ex) { ex.printStackTrace(); } catch (IOException ex) { ex.printStackTrace(); }