Feature support old format (PGP 2.6.x) #205

magks · 2023-03-29T17:38:25Z

Legacy applications may need support for PGP 2.6.x.

BouncyCastle PgpLiteralDataGenerator supports PGP 2.6.x via a constructor taking a bool useOldFormat. Adding support in PgpCore to use that flag by adding a bool property to PGP class UseOldFormat (default false), and a bool arg useFormat to Utilties Write*LiteralData methods with a default value of false to not break any public usage of the methods.

( See https://github.com/neoeinstein/bouncycastle/blob/master/crypto/src/openpgp/PgpLiteralDataGenerator.cs )
PgpLiteralDataGenerator.cs:
///

/// Generates literal data objects in the old format.
/// This is important if you need compatibility with PGP 2.6.x.
///

/// If true, uses old format.
public PgpLiteralDataGenerator(
bool oldFormat)
{
this.oldFormat = oldFormat;
}

PgpLiteralDataGenerator has a constructor that takes a bool indicating whether to use old format. If true, it generates literal data objects in the old format. /// This is important if you need compatibility with PGP 2.6.x. Added bool value, useOldFormat, to all relevant utilities methods constructing PgpLiteralDataGenerator object. Some of methods that instantiate the PgpLiteralDataGenerator don't use the Open() method that can use the old format, so not adding the arg for those utility methods. Default value false to not break any current client usage of the Utilities class. useOldFormat passed to the PgpLiteralDataGenerator constructor. Add property UseOldFormat, pass to WriteStreamToLiteralData BouncyCastle's PgpLiteralDataGenerator has a constructor that takes a bool indicating whether or not to use "oldFormat". This can be set to true to support 2.6.x version of PGP. Including support for this in PgpCore by adding a bool property UseOldFormat to PGP class defaulting to false. Encrypt methods passes UseOldFormat as an argument to Utilities.WriteStreamToLiteralData which wraps the call to the PgpLiteralDataGenerator constructor.

magks · 2023-03-31T19:44:54Z

I just made this PR to illustrate how the support might be added and start a conversation about it. I was tasked with replacing a proprietary PGP package and I was looking into this one. I believe we require the old format support and was investigating how it could be added. I saw it there was a simple way, so requesting support to be added.

I see there is a failed check in my PR. I'm not sure if its related to my changes. I will look into it and fix it if so. But any word from maintainers on whether old format support like in this PR would be added would be much appreciated.