How do I encrypt a PGP message through java's crypto extension?

问题

Currently I'm using bouncy castle's libraries for the actual work and have found an example at sloanseaman.com that (after a little tweaking) works with v1.52.

I've also got a working example from developer.com of how to use the JCE interface and can even drop the bcprov in it and use some of it's algorithms.

public class CryptoUtil {
private static final String ALGORITHM = "IDEA/PGP/NoPadding";

public static void encryptFile(File keyFile, File plainTextFile, File encryptedFile) throws GeneralSecurityException, IOException {
    Cipher desCipher = Cipher.getInstance(ALGORITHM);
    desCipher.init(Cipher.ENCRYPT_MODE, readKeyFromFile(keyFile));
    OutputStream out = new BufferedOutputStream(new FileOutputStream(encryptedFile));
    InputStream in = new BufferedInputStream(new FileInputStream(plainTextFile));
    while (in.available() > 0) {
        // Read the next chunk of bytes...
        byte[] cleartextBytes = new byte[in.available()];
        in.read(cleartextBytes);
        // Now, encrypt them and write them to the encrypted file...
        byte[] encryptedBytes = desCipher.update(cleartextBytes);
        out.write(encryptedBytes, 0, encryptedBytes.length);
    }
    // Take care of any pending padding operations
    out.write(desCipher.doFinal());
    in.close();
    out.flush();
    out.close();

    System.out.println("Encrypted to " + encryptedFile);
}

But no matter what algorithm string I use, I can't get my JCE utility to encrypt the way that the bouncyCastle utility does.

The furthest I've gotten is using "IDEA/PGP/NoPadding" which allows me to encrypt and decrypt within itself, but the BC utility won't decrypt them, saying there's an unknown object in the stream.

Here is my source code

Do you guys know what combination of Algorithm, Mode, and Padding I would need to use for this? Are there other options that I need to apply somehow? I guessing I need to use BC's version of AlgorithmParametersSpi but I haven't figured out how to create that yet

回答1:

You can't. While OpenPGP uses "normal" public/private and symmetric encryption algorithms, trouble starts with the modes. OpenPGP uses its own mode (a modified CFB mode), and also the whole OpenPGP packet syntax is not supported by Java's default libraries.

You'd at least need to reimplement the OpenPGP CFB mode in Java, or somehow rely on Bouncy Castle's implementation.

The OpenPGP CFB mode already includes a replacement for the initialization vector; no additional padding is used/required.

来源：https://stackoverflow.com/questions/32342191/how-do-i-encrypt-a-pgp-message-through-javas-crypto-extension

标签

encryption

pgp

java