Cannot use an encrypted API key with dotnet nuget push on Linux

[FlorianHockmann]

I want to be able to push NuGet packages from Linux to nuget.org without having to specify the API key every time and without having to use Mono to execute nuget.exe.

Unfortunately I'm getting this error message when I try it with dotnet nuget push:

error: Encryption is not supported on non-Windows platforms.

Details about Problem

NuGet product used (NuGet.exe | VS UI | Package Manager Console | dotnet.exe): dotnet.exe

NuGet version (x.x.x.xxx): 4.8.1.0

dotnet.exe --version (if appropriate): 2.1.403

OS version (i.e. win10 v1607 (14393.321)): Linux Subsystem for Windows with Ubuntu 16.04.5 LTS

Detailed repro steps so we can see the same problem

1. Set an API key using nuget.exe:

$> mono nuget.exe setApiKey [someApiKey] -ConfigFile ~/.nuget/NuGet/NuGet.Config

(I specify the ConfigFile here as dotnet nuget apparently ignores the config used by mono nuget.exe, see #4095. Mono is used to set the API key because this functionality is still missing with the dotnet CLI #6437.).

2. Try to push a NuGet package with dotnet nuget push:

$> dotnet nuget push SomePackage.1.0.0.nupkg -s https://api.nuget.org/v3/index.json --force-english-output
error: Encryption is not supported on non-Windows platforms.

Other suggested things

Verbose Logs

Please include verbose logs (NuGet.exe -verbosity detailed | dotnet.exe --verbosity diag | etc...)

--verbosity seems to be not supported by dotnet nuget push:

Specify --help for a list of available options and commands.
error: Unrecognized option '--verbosity'

[rrelyea]

Duplicate of #6437