WCIP-12: Multi-blockchain support

[filips123]

There should be a support to use Walletconnect with Bitcoin and other cryptographies and blockchains. This would increase the scope of WalletConnect and make it possible to use with other systems.

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First other cryptography to support should probably be Bitcoin.

It should have support for sending and signing a transaction and some equivalents to eth_sign, eth_signTypedData and personal_sign. There should be support for "Electrum Bitcoin" signing format (like G4/obhsNpqRdHtCdvwIwWmLA+nPHkPeWEN3KGlsfjZ+gD7QYq906mUsS8MQb7G10hM8cc606/rjcOaGgMIS6gNg=).

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There is already issue #7 which has some similarities:

This would dramatically expand the scope of WalletConnect to not only support other blockchains like for example Bitcoin which already has it's own DID resolver as part of the current W3C spec but also allow WalletConnect to serve as a protocol for DID Authentication for non-blockchain protocols.

[pedrouid]

I've chatted with a lot of projects and I think the best way to tackle this would be to refactor the idea of the session to be around accounts.

Currently it's very tightly coupled to EVM interfacing blockchains which require a chainId (integer) and an array of addresses (hex strings) for accounts.

So in order to keep backwards compatibility with current integrations, it would be good standardize how these different blockchains handle their accounts and chainId equivalent. This could be easily done by defining a string schema that could reference both the interface, network and account representation thus the state of the session would only need to concern with the accounts array.

Following the steps that we've been recently taking with the interchain registry, this would look something similar to this.

Proposal

// multi-chain account schema
interface:network:account

// example 1 - ethereum mainnet
evm:eip155-1:0x16ab756f0b36e2da32BFA1A6Ec78A4C52Fe97d18

// example 2 - bitcoin mainnet
utxo:bitcoin-mainnet:3JKr1213uKtMbymvtxtuie5twTKgniEp2h

// example 3 - cosmos hub
cosmos:cosmos-hub2:cosmos1wgc2ufn3rzg6cnh7g7yy8pl9vzvctutg92y8g3

// example 4 - binance chain
cosmos:binance-chain-tigris:bnb16zkqzg46kwyyelws9f444eh32zwdvlzlmmhdh7

So since we remove the chainId from the protocol, the dapp will no longer request for chainId on session request but instead it will be an array of requestedAccounts that could be as broad as
as the interface or specific to the network string.

Example 1

// request 1
["evm", "cosmos"]

// response 1
["evm:eip155-1:0x16ab756f0b36e2da32BFA1A6Ec78A4C52Fe97d18", "cosmos:cosmos-hub2:cosmos1wgc2ufn3rzg6cnh7g7yy8pl9vzvctutg92y8g3", cosmos:binance-chain-tigris:bnb16zkqzg46kwyyelws9f444eh32zwdvlzlmmhdh7"]

Example 2

// request 1
[ "cosmos:cosmos-hub2"]

// response 1
["cosmos:cosmos-hub2:cosmos1wgc2ufn3rzg6cnh7g7yy8pl9vzvctutg92y8g3"]

[pedrouid]

We have finally merged the first standards for CAIPs (Chain Agnostic Improvement Proposals) which will help bridge application interfaces across chains

Given that this work has built the first standard for chain agnostic chainId's, I would like to propose that account references in WalletConnect will extends the CAIP-2 by specifying the following for WCIP-12:

Proposal

// multi-chain account schema
chain_id:    namespace + ":" + reference + ":" + account
namespace:   [-a-z0-9]{3,16}
reference:   [-a-zA-Z0-9]{1,47}
account:     [a-zA-Z0-9]{1,63}

// example 1 - ethereum mainnet
eip155:1:0x16ab756f0b36e2da32BFA1A6Ec78A4C52Fe97d18

// example 2 - bitcoin mainnet
bip122:000000000019d6689c085ae165831e93:3JKr1213uKtMbymvtxtuie5twTKgniEp2h

// example 3 - cosmos hub
cosmos:cosmoshub-3:cosmos1wgc2ufn3rzg6cnh7g7yy8pl9vzvctutg92y8g3

// example 4 - binance chain
cosmos:Binance-Chain-Tigris:bnb16zkqzg46kwyyelws9f444eh32zwdvlzlmmhdh7

Therefore a session request would use CAIP-2 blockchain namespaces or id's to specify which accounts wish to retrieve from a wallet and the wallet should respond with WCIP-12 account references. Here are some updated examples for account requests:

Example 1

// request 1
["eip155", "cosmos"]

// response 1
["eip155:1:0x16ab756f0b36e2da32BFA1A6Ec78A4C52Fe97d18", "cosmos:cosmoshub-3:cosmos1wgc2ufn3rzg6cnh7g7yy8pl9vzvctutg92y8g3", cosmos:Binance-Chain-Tigris:bnb16zkqzg46kwyyelws9f444eh32zwdvlzlmmhdh7"]

Example 2

// request 1
[ "cosmos:cosmoshub-3"]

// response 1
["cosmos:cosmoshub-3:cosmos1wgc2ufn3rzg6cnh7g7yy8pl9vzvctutg92y8g3"]

[pedrouid]

With the growing adoption of the CAIPs, it made more sense to define this standard as part of these standards.

Thus I've create a chain-agnostic account id specification referenced as CAIP-10 which should be used for multi-blockchain support on WalletConnect

Proposal

// SYNTAX

account_id:        account_address + "@" + chain_id
account_address:   [a-zA-Z0-9]{1,63}
chain_id:          [:-a-zA-Z0-9]{5,64}

// EXAMPLES

# Ethereum mainnet
0xab16a96d359ec26a11e2c2b3d8f8b8942d5bfcdb@eip155:1

# Bitcoin mainnet 
128Lkh3S7CkDTBZ8W7BbpsN3YYizJMp8p6@bip122:000000000019d6689c085ae165831e93

# Cosmos Hub
cosmos1t2uflqwqe0fsj0shcfkrvpukewcw40yjj6hdc0@cosmos:cosmoshub-3

# Binance Chain
bnb16zkqzg46kwyyelws9f444eh32zwdvlzlmmhdh7@cosmos:Binance-Chain-Tigris

Therefore a session request would use CAIP-2 blockchain namespaces or id's to specify which accounts wish to retrieve from a wallet and the wallet should respond with WCIP-12 account references. Here are some updated examples for account requests:

Example 1

// request 1
["eip155", "cosmos"]

// response 1
["0x16ab756f0b36e2da32BFA1A6Ec78A4C52Fe97d18@eip155:1", "cosmos1wgc2ufn3rzg6cnh7g7yy8pl9vzvctutg92y8g3@cosmos:cosmoshub-3", bnb16zkqzg46kwyyelws9f444eh32zwdvlzlmmhdh7@cosmos:Binance-Chain-Tigris"]

Example 2

// request 1
[ "cosmos:cosmoshub-3"]

// response 1
["cosmos1wgc2ufn3rzg6cnh7g7yy8pl9vzvctutg92y8g3@cosmos:cosmoshub-3"]