generate keys using PGPainless

[tomholub]

part of #1051

PGPainless can be used directly to generate ECC / RSA2048 / RSA 3072 / RSA 4096 keys.

        PGPSecretKeyRing secretKeys = PGPainless.generateKeyRing()
                .withPrimaryKey(KeySpec.getBuilder(KeyType.RSA(RsaLength._3072))
                        .withKeyFlags(KeyFlag.CERTIFY_OTHER, KeyFlag.SIGN_DATA, KeyFlag.ENCRYPT_COMMS)
                        .withDefaultAlgorithms())
                .withPrimaryUserId("primary@user.id")
                .setExpirationDate(expiration)
                .withoutPassphrase()
                .build();

You can also add more user ids this way, or pass phrase. Can completely drop dependency on Node for keygen.

I imagine right now we generate first and create a pass phrase later? If so, we could instead ask for pass phrase first, then generate.

[tomholub]

Correction - it's better to use the simplified API:

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

[tomholub]

There should be ECC keyring option there too that's as simple as this.

[DenBond7]

@tomholub Please look at this. Need to port getting keywords from Node to complete this issue

flowcrypt-android/FlowCrypt/src/main/java/com/flowcrypt/email/extensions/PGPKeyRingExt.kt

Line 48 in 0558575

keywords = ""//fix me

[DenBond7]

@tomholub

When I use the following code to generate a key (use ed25519)

PGPainless.generateKeyRing().simpleEcKeyRing(
            UserId.nameAndEmail(accountEntity.displayName
                ?: accountEntity.email, accountEntity.email), passphrase)

I receive the following error when I create an encrypted message :

{
   "error":{
      "message":"Error: Error encrypting message: Could not find valid key packet for encryption in key 2e5aaad3795c3bec",
      "stack":"Error: Error encrypting message: Could not find valid key packet for encryption in key 2e5aaad3795c3bec\n    at [eval]:66772:15"
   }
}