Legacy transaction signing can bind a chain identifier.
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A payment form can name the jurisdiction where it is intended to be used.
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From a public address to a verified signatureStep 1 / 4
An address is public receiving information. It is not the private key that authorizes actions.
An address is public receiving information. It is not the private key that authorizes actions.The local signing system uses secret authorization material. It produces a signature; the private key is not sent along with it.A verifier checks the signed request under the account’s rules. A valid signature does not by itself prove that the action is safe.Balances belong to network state. A wallet is an interface and signing system, not a box containing coins.
Animated local teaching model. No wallet, RPC or live blockchain data. Some labels and hashes are abbreviated for readability.
Identify the original replay issue
Without suitable chain binding, a signed transaction can potentially be valid on another chain with compatible state and rules. A network name in a wallet display is insufficient by itself.
Read the legacy mechanism
EIP-155 changes protected legacy signing data and the v interpretation to incorporate chainId. It is a specific transaction-signature convention.
Separate newer transaction formats
Typed transactions define their own field and signing rules. Do not apply the legacy v formula as a universal parser for every signature.
Keep application messages separate
A chain-protected transaction does not automatically protect arbitrary off-chain messages accepted by a contract. Those messages need their own domain and replay rules.
Map the protocol concept
protected legacy signing includes chainId context
typed transactions have their own schema
application signatures need separate domain and nonce rules
A conceptual model. Exact fields, limits and processing rules must be checked against the intended network fork.
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Does EIP-155 automatically add replay protection to every off-chain message?