Wishlist / reminders for a new protocol format

[felixfontein]

This issue is to keep track of things that should be changed / improved when we want to update SOPS's encrypted file format.

• MAC:

  • Do not ignore null values: MAC is not changed when add null values in yaml file #828
  • Include keys in MAC computation to avoid problem described in Question: How to manage merge conflicts with MAC signature #52 (comment)

• Encrypted data:

  • Add padding to not fully reveal the length of the clear text data (Encrypted data reveal the length of the clear text data #815)
  • Eventually even encrypt null: MAC is not changed when add null values in yaml file #828 (comment)
  • Use protobuf instead of own format: Encrypted data reveal the length of the clear text data #815 (comment)