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Red Cup Engineering

Sign-in-with-X on an x402 402: stateless wallet login for returning agents neighborhood

The current page first, followed by its outgoing and incoming relations.

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Sign-in-with-X on an x402 402: stateless wallet login for returning agents

How an x402 seller attaches a CAIP-122 sign-in challenge to its 402, verifies EIP-191 and EIP-1271 proofs with stateless HMAC nonces, and grants wallets access.

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