There should be API allowing to check if an archive is protected.
Provide a way for users to check whether a stream is a valid zip archive. Include a CRC check as well.
Add functionality for the ZipPackage to span across multiple files.
According to the specification, the Enhanced Deflating algorithm is similar to Deflate but uses a sliding dictionary of up to 64K.
Provide a simple method to detect that a password for a ZIP file is not valid.
The current implemention usually throws an exception (which does not definitively identify the password as wrong), but not always. Sometimes it just returns corrupt data.
It would be nice to either have a typed exception consistently thrown, or a method to specifically check for an invalid password.
When updating ZIP archive, there is no need for loading it fully in the memory. Each entry is represented as a separate stream; when the ZipArchive is disposed, each entry is written in the OutputStream which is MemoryStream. When an entry is written in the OutputStream it is read from the source file if it is not changed. The MemoryStream is used because the source file is needed to get the entries contents. A temporary file can be used instead and there will be no need of the memory stream, so that large files will be updated without using much memory (which causes OutOfMemoryException).