description
A specification to store wallet address of multiple chain on Hypersign DID

Blockchain Account Id

EIP-155 - Identifying a blockchain within Ethereum ecosystem

ChainID was introduced in EIP-155 to prevent replay attacks between the main ETH and ETC chain since they both have same networkID 1. Its an additional way to tell the chains are apart. So, now due to EIP-155, ETH has a chainId 1 whereas ETC has a chainID of 61. (see chainlist here)

What is replay attack?

In EVM ecosystem, same account address can be used in multiple chains. Hence it was possible to send same transactions on multiple chains - hence the term replay attack. For example, it is possible to issue a fund transferon a testchain and then perform same transfer on Mainnet. This vulnerability is because that the same account (corresponding to same private key) can exists in any EVM chains.

Specification

To fix this issue Ethereum allowed insertions of ChainID data in the signed transaction.

So earlier we generated transaction hash using these values:

(nonce, gasprice, startgas, to, value, data)

But now, we will generate transaction hash using these values:

(nonce, gasprice, startgas, to, value, data, chainid, 0, 0)

CAIP-2 - Identifying a blockchain in any ecosystem

Its a way to identify different blockchains (e.g. Ethereum Mainnet, Cosmos hub, Bitcoin etc) in developer-friendly manner.

We often need to reference a blockchain to state where some asset like token or smart contract is located. In Ethereum the EIP-155 chain ID is used most of the time but with Ethereum Chain ID, you can not reference other blockchains like Bitcoin or Cosmos.

Specification:

chain_id:    namespace + ":" + reference
namespace:   [-a-z0-9]{3,8}                # Class of similar chains, e.g cosmos, eip155 etc
reference:   [-_a-zA-Z0-9]{1,32}           # A way to identify a blockchain within a given namespace

E.g:

# Ethereum mainnet
eip155:1

# Cosmos Hub (Tendermint + Cosmos SDK)
cosmos:cosmoshub-2
cosmos:cosmoshub-3
cosmos:hid-jagrat

# Litecoin
bip122:12a765e31ffd4059bada1e25190f6e98

CAIP-10 - Identifying a walletaddress in any ecosystem

CAIP-10 extends CAIP-2 to the account level. This specification facilitate specifying accounts for any blockchains. Its chain-agnostic protocol for communication between dapps and wallets ¹that was independent of any blockchain but provide the flexibility to be backwards compatible with existing applications.

It is useful for both decentralized applications (dApps) and wallets to communicate user accounts for multiple chains using string identifiers specific to each chain.

Specification:

The account_id is a case-sensitive string in the form

account_id:        chain_id + ":" + account_address
chain_id:          [-a-z0-9]{3,8}:[-_a-zA-Z0-9]{1,32} (See [CAIP-2][])
account_address:   [-.%a-zA-Z0-9]{1,128}

E.g:

# Ethereum mainnet (canonicalized with [EIP-55][] checksum)
eip155:1:0xab16a96D359eC26a11e2C2b3d8f8B8942d5Bfcdb

# Cosmos Hub
cosmos:cosmoshub-3:cosmos1t2uflqwqe0fsj0shcfkrvpukewcw40yjj6hdc0
cosmos:hid-jagrat:hid1yya5gl4v6sj3qn0l06ngz0uuxg995mm9ps087u

# Bitcoin mainnet
bip122:000000000019d6689c085ae165831e93:128Lkh3S7CkDTBZ8W7BbpsN3YYizJMp8p6

{% hint style="info" %} CAIP-2 describes blockchain Id whereas CAIP-10 describes account Id {% endhint %}