I don't want to figure out how tar works everytime I want to encrypt a folder.

Golang provides archive/tar

encrypting a file or folder should be the same command

Does aes gcm counter wraps around in go? That would be an issue in go's std lib but I still need to check

The best way to integrate Eureka in an OS should be to add right-click options:

• encrypt when right-clicking on a file/folder
• decrypt when right-clicking on something.encrypted
• encrypt when right-clicking on the background of a folder?

The user should be prompted with a box afterwards, telling him the key.

• windows
• linux
• macOS

Is it, really, a one-time key? I can use it over and over to decrypt the same encrypted file. Perhaps it isn't one-time, but unique?

The current license reads

This is the license.

Is this intentional? Can you switch to something like https://www.apache.org/licenses/LICENSE-2.0?

• tell the user to pass a key when one is missing (or re-print usage)
• add a .encrypted to the real file name instead of losing the filename+ext

Have a eureka icon for .encrypted files

Right now we use 644, should we change that to 600?

Before encrypting a file or a folder, let's compress it automatically?

We could attempt to detect if the file has already been compressed, but I expect that not much people will compress files in advance... so maybe useless complexity.

golang provides archive/zip for that

https://golang.org/pkg/archive/tar/

but no code to compress a folder, so you have to write it yourself...

Otherwise anybody can see the key doing ps aux.

Make it really easy to install Eureka

• binaries on github
• go get
• homebrew
• chocolatey
• apt
• yum
• pacman
• easy_install ?
• rpm
• curl/wget
• msi package for windows?

-encrypt
Argument is not necessary as this project does only one thing.

-file
Is not necessary too. This project only encrypts files, not strings, its not necessary.

-decrypt
This can be detected using file suffix. Such as .enc or .encrypted. Not necessary too.

You're making this project much more complicated than it should be. Please, make it simple, like Go. :)

Make it clear that the key must not be used twice to encrypt different files. Why not just use a random nonce and prepend it to the encrypted file?

rust and oh-my-zsh both have a command using wget piping to a shell that one can copy/paste in their terminal to install them.

How to install Eureka?

• msi package? https://mh-cbon.github.io/go-msi/
• path of install? Probably %ProgramFiles%

How to have Encrypt context menu + icon

HKEY_CLASSES_ROOT
   *
      shell
         encrypt
            command
               (Default) = "C:\Program Files\eureka\eureka.exe" -encrypt -file "%1"
         getEureka
            command
               (Default) = "C:\Program Files\eureka\eureka.exe" -about
   .encrypted
      DefaultIcon
         (Default) = "C:\Program Files\eureka\eureka.ico"
      shell
         encrypt
            command
               (Default) = "C:\Program Files\eureka\eureka.exe" -encrypt -file "%1"
         decrypt
            command
               (Default) = "C:\Program Files\eureka\eureka.exe" -decrypt -file "%1"

How to prompt for the key?

Probably, will need QT or a GUI