Claims & Proofs: cleanup args and terminology

[tbfleming]

Current verifier args (e.g. verifyec-sys):

struct Claim
{
    AccountNumber     service;
    std::vector<char> rawData;
};

struct VerifyArgs
{
   Checksum256       transactionHash;
   Claim             claim;
   std::vector<char> proof;
};

The transactionHash arg forces use of sha256, which hurts upgradeability since the native code fills it.

Claim and Proof aren't standard terminology. The current use case is Public Key and Signature, but we plan to define more uses in the future (e.g. Antelope Action and Merkle Proof) and it's possible for independent service authors to define their own uses.

[tbfleming]

Here's one possible solution for the terminology problem:

• Rename them to PublicKey and Signature since this is the majority use case
• Abuse those terms for the minority use cases. e.g. an Antelope action is a psibase public key and a Merkle proof is a psibase signature.

[swatanabe]

* Abuse those terms for the minority use cases. e.g. an Antelope action is a psibase public key and a Merkle proof is a psibase signature.

A merkle tree can be seen as a signature scheme if you squint at it right. In fact, a slightly different breakdown would make this seem almost normal:

• public key: merkle root
• data: Antelope action
• signature: merkle proof

Then, a Claim can be defined as a public key + either a tag indicating the whole transaction or an octet-string.