[FR] Support for Encrypted containers

[Kein]

It looks like no known file format is compatible with -EncryptionKeys=<KeyFile>
Neither the dummy that ZT itself generates:

"EncryptionKey":{"Name":null,"Guid":null,"Key":null},"SigningKey":null,"bEnablePakSigning":false,"bEnablePakIndexEncryption":false,"bEnablePakIniEncryption":false,"bEnablePakUAssetEncryption":false,"bEnablePakFullAssetEncryption":false,"bDataCryptoRequired":true,"PakEncryptionRequired":true,"PakSigningRequired":true,"SecondaryEncryptionKeys":null}

Nor the UnrealPak one:

https://raw.githubusercontent.com/allcoolthingsatoneplace/UnrealPakTool/master/Crypto.json

LogIoStoreTools: Warning: Failed to parse string 'EncryptionKey' as a valid Guid for encryption key
LogIoStoreTools: Warning: Failed to parse string 'SigningKey' as a valid Guid for encryption key
LogIoStoreTools: Warning: Failed to parse string 'bEnablePakSigning' as a valid Guid for encryption key
LogIoStoreTools: Warning: Failed to parse string 'bEnablePakIndexEncryption' as a valid Guid for encryption key
LogIoStoreTools: Warning: Failed to parse string 'bEnablePakIniEncryption' as a valid Guid for encryption key
LogIoStoreTools: Warning: Failed to parse string 'bEnablePakUAssetEncryption' as a valid Guid for encryption key
LogIoStoreTools: Warning: Failed to parse string 'bEnablePakFullAssetEncryption' as a valid Guid for encryption key
LogIoStoreTools: Warning: Failed to parse string 'bDataCryptoRequired' as a valid Guid for encryption key
LogIoStoreTools: Warning: Failed to parse string 'PakEncryptionRequired' as a valid Guid for encryption key
LogIoStoreTools: Warning: Failed to parse string 'PakSigningRequired' as a valid Guid for encryption key
LogIoStoreTools: Warning: Failed to parse string 'SecondaryEncryptionKeys' as a valid Guid for encryption key

[narknon]

What about the format in the readme?