how to write my own signer

Question

For a research project, I'm trying to implement my own signer, such that I can run tezos-client import secret key ALIAS "http://..." and then I can use tezos-client to transfer and tezos-baker to bake.

What API does my server need to implement in order for this to work? I've seen a few projects that intend to do this like https://github.com/tacoinfra/remote-signer and I'm trying to understand if the API they supply is what I need:

• POST /keys/<key_hash>
• GET /keys/<key_hash>
• GET /authorized_keys

Thanks

Answer 1

I've got here the beginning of an answer, after reviewing the code for a few libraries like:

• tezos-hsm-signer
• tezos-azure-hsm-signer
• remote-signer

I found that it's pretty simple and to implement the signer we need to create a server with the following routes:

• GET /authorized_keys

  Retrieve the public keys that can be used to authenticate signing commands. If the empty object is returned, the signer has been set to accept unsigned commands. (most signers I saw just return empty object)

  returns {authorized_keys: [pkh]}

• GET /keys/:pkh

  Retrieve the public key of a given remote key (=public key hash)

  returns {public_key: pk}

• POST /keys/:pkh

  Sign a piece of data with a given remote key

  receives: a string of bytes

  returns {signature: Signature.encoding}

This should be checked as it seems that when signer gets a block (for baking) it expects a different signarture

My main problem right now is to sign the data.