[egor-n]

There's an example on how to encrypt the files before sending them to the server:

  # Encrypt files with password using gpg 
  $ cat /tmp/hello.txt|gpg -ac -o-|curl -X PUT --upload-file "-" https://transfer.sh/test.txt 
  
  # Download and decrypt 
  $ curl https://transfer.sh/1lDau/test.txt|gpg -o- > /tmp/hello.txt

[nl5887]

Exactly, who trusts server side encryption anyway?

[xorcist]

The first cat does absolutely nothing in your example.

[pmarreck]

are you sure? how else would you pipe to GPG?

[yuubi]

Just redirect gpg's input from the file?

    gpg ... < hello.txt | curl ...

Its stdin will be the file instead of a pipe, but few programs care about the difference and fewer still in such a way that you'd prefer to use the pipe.