Re-enable encrypt/decrypt on keypair

[davidrhodus]

• I'm submitting a request to revet the changes in Remove support for encrypt/decrypt on keypair #1762 to Re-enable encrypt/decrypt on keypair

• Bug report
• Feature request
• Support request
• Other

• What is the current behavior and expected behavior?
  Our application is expecting the encrypt/decrypt to be on the keypair object

• What is the motivation for changing the behavior?

We currently utilize encrypt/decrypt within out Substrate based project. We are requesting this feature be added back into the polkadot.js code.

[jacogr]

The problem is that it is broken - it does not work as intended sharing messages between various crypto types. Hence being removed.

[jacogr]

Can you just walk me through how you are using the above and which problem you are solving/usecase you are addressing?

The reason for asking is that, while the sharing-between-different-pairs was broken (with weird cases), there could be other solutions that addresses specific usecases. (For instance vault-like functionality that only encrypts data for known pairs, etc. This is opposed to the "general message sharing" the original tried to do.)