pgpainless/README.md

# PGPainless - Use OpenPGP Painlessly!

PGPainless aims to make using OpenPGP in Java projects as simple as possible.
It does so by introducing an intuitive Builder structure, which allows easy 
setup of encryption / decrytion operations, as well as straight forward key generation.

PGPainless is based around the Bouncycastle java library and can be used on Android down to API level 9.

### NOTE: PGPainless is in a *very* early state of development and should under no circumstances be used for serious production usage yet.

## How to use PGPainless

The entry point to the API is the `PGPainless` class. Here you can find methods for a quick start :)

### Generate Keys

The first thing you probably want to do is generate you some nice tasty Key Pairs. The most straight forward way to do so is by calling

```
        PGPSecretKeyRing keyRing = PGPainless.generateKeyRing()
                .simpleRsaKeyRing("Juliet <juliet@montague.lit>", RsaLength._4096);
```

but feel free to explore the API further. PGPainless allows you to create Key Pairs consisting of a master key plus several sub keys, even with different algorithms at the same time!
Take for example a look at this delicious key:

```
        PGPSecretKeyRing keyRing = PGPainless.generateKeyRing()
                .withSubKey(
                        KeySpec.getBuilder(ECDSA.fromCurve(EllipticCurve._P256))
                        .withKeyFlags(KeyFlag.SIGN_DATA)
                        .withDetailedConfiguration()
                        .withDefaultSymmetricAlgorithms()
                        .withDefaultHashAlgorithms()
                        .withPreferredCompressionAlgorithms(CompressionAlgorithm.ZLIB)
                        .withFeature(Feature.MODIFICATION_DETECTION)
                        .done())
                .withSubKey(
                        KeySpec.getBuilder(ECDH.fromCurve(EllipticCurve._P256))
                        .withKeyFlags(KeyFlag.ENCRYPT_COMMS, KeyFlag.ENCRYPT_STORAGE)
                        .withDefaultAlgorithms())
                .withMasterKey(
                        KeySpec.getBuilder(RSA_GENERAL.withLength(RsaLength._8192))
                                .withKeyFlags(KeyFlag.SIGN_DATA, KeyFlag.CERTIFY_OTHER)
                                .withDefaultAlgorithms())
                .withPrimaryUserId("Juliet <juliet@montague.lit>")
                .withPassphrase("romeo_oh_Romeo<3")
                .build();
```

### Encrypt / Sign Data

Encrypting and signing data is pretty straight forward as well.
```
        EncryptionStream encryptor = PGPainless.createEncryptor()
                .onOutputStream(targetOuputStream)
                .toRecipients(publicKeyRings)
                .usingSecureAlgorithms()
                .signWith(secretKeyDecryptor, signingKeyRing)
                .noArmor();
```

The resulting `EncryptionStream` can then be used to encrypt data like follows:

```
        Streams.pipeAll(sourceInputStream, encryptor);
        sourceInputStream.close();
        encryptor.close();
```

The encrypted data will be written to the provided `targetOutputStream`.

Additionally you can get information about the encrypted data by calling

```
        PainlessResult result = encryptor.getResult();
```

That object will contain information like to which keys the message is encrypted, which keys were used for signing and so on.

### Decrypt / Verify Encrypted Data

To process incoming encrypted / signed data, just do the following:

```
        DecryptionStream decryptor = PGPainless.createDecryptor()
                .onInputStream(sourceInputStream) // insert encrypted data here
                .decryptWith(secretKeyDecryptor, secretKey)
                .verifyWith(trustedKeyIds, senderKeys)
                .ignoreMissingPublicKeys()
                .build();
```

Again, the resulting `DecryptionStream` can be used like a normal stream.

```
        Streams.pipeAll(decryptor, targetOutputStream);
        decryptor.close();
```

*After* the `DecryptionStream` was closed, you can get metadata about the processed data by retrieving the `PainlessResult`.
Again, this object will contain information about how the message was encrypted, who signed it and so on.

```
        PainlessResult result = decryptor.getResult();
```

## About
PGPainless is a by-product of my [Summer of Code 2018 project](https://vanitasvitae.github.io/GSOC2018/).
For that project I was in need of a simple to use OpenPGP library.

Originally I was going to use [Bouncy-GPG](https://github.com/neuhalje/bouncy-gpg) for my project,
but ultimately I decided to create my own OpenPGP library which better fits my needs.

However, PGPainless is heavily influenced by Bouncy-GPG and  I would definitely recommend you to
use it instead of PGPainless if you want a more mature, better tested code base.