我有一个应该写入文件系统的'javax.mail.Message'对象。我使用版本1.5.5的javax.mail（com.sun.mail）
javax.mail.Message message = buildMessage(...);
message.writeTo(new FileOutputStream("message.plain"));
现在消息被写入文件。但我怎样才能加密＆amp;解密这个文件？我在下面发布了我的示例，但此代码失败。
我的示例代码：
static byte[] salt = new byte[8];
static {
SecureRandom random = new SecureRandom();
random.nextBytes(salt);
}
public final void test() throws Exception {
Message message = buildTestMessage(...);
SecretKey secret = encode(message, new FileOutputStream("test.encrypted"), "01234567".toCharArray());
Message message2 = decode(new FileInputStream("test.encrypted"), "01234567".toCharArray());
// out sth. like from@domain <--> null
System.out.println(message.getFrom()[0] + " <--> " + message2.getFrom());
}
private Message decode(
InputStream mailFileInputStream, char[] password) throws NoSuchAlgorithmException, NoSuchPaddingException,
InvalidKeyException, MessagingException, IOException, InvalidKeySpecException {
/* Derive the key, given password and salt. */
SecretKeyFactory factory = SecretKeyFactory.getInstance("PBEWithHmacSHA256AndAES_128");
KeySpec spec = new PBEKeySpec(password, salt, 65536, 256);
SecretKey tmp = factory.generateSecret(spec);
SecretKey secret = new SecretKeySpec(tmp.getEncoded(), "PBEWithHmacSHA256AndAES_128");
Cipher cipher = Cipher.getInstance("PBEWithHmacSHA256AndAES_128");
cipher.init(Cipher.DECRYPT_MODE, secret);
InputStream is = new CipherInputStream(mailFileInputStream, cipher);
Properties props = new Properties();
Session session = Session.getDefaultInstance(props, null);
Message message = new MimeMessage(session, is );
return message;
}
static SecretKey encode(
Message message,
FileOutputStream out,
char[] password) throws Exception {
/* Derive the key, given password and salt. */
SecretKeyFactory factory = SecretKeyFactory.getInstance("PBEWithHmacSHA256AndAES_128");
KeySpec spec = new PBEKeySpec(password, salt, 65536, 256);
SecretKey tmp = factory.generateSecret(spec);
SecretKey secret = new SecretKeySpec(tmp.getEncoded(), "PBEWithHmacSHA256AndAES_128");
Cipher cipher = Cipher.getInstance("PBEWithHmacSHA256AndAES_128");
cipher.init(Cipher.ENCRYPT_MODE, secret);
OutputStream cos = new CipherOutputStream(out, cipher);
message.writeTo(cos);
cos.close();
return secret;
}
补充：Upvote我的问题，我将你的答案标记为已接受。我有一个问题禁令，没有任何未解决的问题或没有关注我的问题！
答案 0 :(得分：1)
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.KeySpec;
import java.util.Base64;
import java.util.Date;
import java.util.Optional;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.Session;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;
public class Stackoverflow {
private static final int keySize = 128;
static byte[] saltForThisRun = new byte[8];
static {
SecureRandom random = new SecureRandom();
random.nextBytes(saltForThisRun);
}
public static void main(
String[] args) throws Exception {
Message message = buildTestMessage("from@null.org", new String[] { "to@null.org", "to2@null.org" },
"Subject is needed here", Optional.of("This is just a text"), Optional.empty());
char[] password = "password".toCharArray();
String encryptedMsg = encrypt(password, saltForThisRun, message);
System.out.println("encryptedMsg: " + encryptedMsg);
Message message2 = decrypt(password, saltForThisRun, encryptedMsg);
// out sth. like from@domain <--> null
System.out.println(message.getFrom()[0] + " <--> " + message2.getFrom()[0]);
}
private static Message decrypt(
char[] password,
byte[] salt,
String base64CipherText) throws EncryptionException {
try {
SecretKey secretKey = generateKey(password, salt, keySize);
byte[] initializationVector = createInitializationVector(keySize);
Cipher aesCipherForDecryption = Cipher.getInstance("AES/CBC/PKCS5PADDING");
aesCipherForDecryption.init(Cipher.DECRYPT_MODE, secretKey, new IvParameterSpec(initializationVector));
byte[] decryptedByteCipherText = Base64.getDecoder().decode(base64CipherText);
byte[] byteDecryptedMessage = aesCipherForDecryption.doFinal(decryptedByteCipherText);
return createMessageFromBytes(byteDecryptedMessage);
} catch (IllegalStateException | InvalidKeyException | InvalidAlgorithmParameterException
| NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeySpecException
| IllegalBlockSizeException | BadPaddingException | MessagingException e) {
throw new EncryptionException(String.format("Unable to enrypt message due to: %s", e.getMessage()), e);
}
}
/**
*
* @param password
* @param salt
* @param message
* @param charArray
* @return Base64 encoded CipherText
* @throws EncryptionException
* If sth. goes wrong
*/
private static String encrypt(
char[] password,
byte[] salt,
Message message) throws EncryptionException {
try {
/**
* Step 1. Generate an AES key with password and salt
*
*/
SecretKey secretKey = generateKey(password, salt, keySize);
System.out.println(secretKey.getEncoded().length);
/**
* Step 2. Generate an Initialization Vector (IV)
* a. Use SecureRandom to generate random bits
* The size of the IV matches the blocksize of the cipher (e.g. 128 bits for AES)
* b. Construct the appropriate IvParameterSpec object for the data to pass to Cipher's init() method
*/
byte[] initializationVector = createInitializationVector(keySize);
/**
* Step 3. Create a Cipher by specifying the following parameters
* a. Algorithm name - here it is AES
* b. Mode - here it is CBC mode
* c. Padding - e.g. PKCS7 or PKCS5
*
* Must specify the mode explicitly as most JCE providers default to ECB mode!!
*/
Cipher aesCipherForEncryption = Cipher.getInstance("AES/CBC/PKCS5PADDING");
/**
* Step 4. Initialize the Cipher for Encryption
*/
aesCipherForEncryption.init(Cipher.ENCRYPT_MODE, secretKey, new IvParameterSpec(initializationVector));
/**
* Step 5. Encrypt the Data
* a. Declare / Initialize the Data. Here the data is of type String
* b. Convert the Input Text to Bytes
* c. Encrypt the bytes using doFinal method
*/
byte[] byteCipherText = updateCipherWithMessage(aesCipherForEncryption, message);
return new String(Base64.getEncoder().encode(byteCipherText));
} catch (IllegalBlockSizeException | BadPaddingException | IOException | MessagingException
| InvalidKeyException | InvalidAlgorithmParameterException | NoSuchAlgorithmException
| NoSuchPaddingException | InvalidKeySpecException e) {
throw new EncryptionException(String.format("Unable to enrypt message due to: %s", e.getMessage()), e);
}
}
private static MimeMessage createMessageFromBytes(
byte[] decodedBytes) throws MessagingException {
InputStream is = new ByteArrayInputStream(decodedBytes);
Session session = null;
return new MimeMessage(session, is);
}
private static byte[] updateCipherWithMessage(
Cipher cipher,
Message message) throws IOException, MessagingException, IllegalBlockSizeException, BadPaddingException {
ByteArrayOutputStream os = new ByteArrayOutputStream();
try {
message.writeTo(os);
return cipher.doFinal(os.toByteArray());
} finally {
os.close();
}
}
private static byte[] createInitializationVector(
int keyLength) {
// Save the IV bytes or send it in plaintext with the encrypted data so you can decrypt the data later
byte[] iv = new byte[keyLength / 8];
SecureRandom prng = new SecureRandom();
prng.nextBytes(iv);
return iv;
}
private static SecretKey generateKey(
char[] password,
byte[] salt,
int keySize) throws InvalidKeySpecException, NoSuchAlgorithmException {
int nIterations = 65536;
SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
KeySpec spec = new PBEKeySpec(password, salt, nIterations, keySize);
SecretKey tmp = factory.generateSecret(spec);
return new SecretKeySpec(tmp.getEncoded(), "AES");
}
private static Message buildTestMessage(
String from,
String[] to,
String subject,
Optional<String> text,
Optional<String> html) throws Exception {
String replyto = from;
Session session = null;
Message message = new MimeMessage(session);
Multipart multiPart = new MimeMultipart("alternative");
try {
if (text.isPresent()) {
MimeBodyPart textPart = new MimeBodyPart();
textPart.setText(text.get(), "utf-8");
multiPart.addBodyPart(textPart);
}
if (html.isPresent()) {
MimeBodyPart htmlPart = new MimeBodyPart();
htmlPart.setContent(html, "text/html; charset=utf-8");
multiPart.addBodyPart(htmlPart);
}
message.setContent(multiPart);
if (from != null) {
message.setFrom(new InternetAddress(from));
} else
message.setFrom();
if (replyto != null)
message.setReplyTo(new InternetAddress[] { new InternetAddress(replyto) });
else
message.setReplyTo(new InternetAddress[] { new InternetAddress(from) });
InternetAddress[] toAddresses = new InternetAddress[to.length];
for (int i = 0; i < toAddresses.length; i++) {
toAddresses[i] = new InternetAddress(to[i]);
}
message.setRecipients(Message.RecipientType.TO, toAddresses);
message.setSubject(subject);
message.setSentDate(new Date());
return message;
} catch (Exception e) {
e.printStackTrace();
System.out.println("Exception: " + e.getMessage());
throw e;
}
}
}