Missing MPI for the signature

[tobiasjungnickel]

• ObjectivePGP version: 0.15.0
• Platform (iOS/macOS): iOS
• Installation method (CocoaPods/Carthage/...): CocoaPods

Description

After exporting a read key using ObjPGP i receive the following error
ERROR: -[PGPSignaturePacket buildFullSignatureBodyData]/287 Missing MPI for the signature..
Then when i want to read this Data the app terminates.
*** Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[_NSZeroData getBytes:range:]: range {0, 1} exceeds data length 0'.

That's part of the way we handle keys, but just produces an error with the attached one.

key0x59C6EC9C9405A111.asc.zip

Steps to reproduce

Sample code to reproduce the issue:

let allKeys = try ObjectivePGP.readKeys(fromPath: url.path)
let keyData = try allKeys.first!.export()
let reimport = try ObjectivePGP.readKeys(from: keyData)