EIP-191 signer (e.g. viem account.signMessage).
Expected origin (e.g. "https://ps.example.com").
HTTP method (e.g. "GET").
Request URI/path (e.g. "/v1/data/instagram.profile").
Optionalbody?: Uint8Array<ArrayBufferLike>Optional request body — when present, used to compute bodyHash.
Optionaliat?: numberIssued-at (unix seconds). Defaults to now.
Optionalexp?: numberExpiry (unix seconds). Defaults to iat + 300.
OptionalgrantId?: stringOptional grant id, attached as the grantId claim.
OptionalbodyHash?: stringPre-computed bodyHash claim — overrides body.
The full header value ("Web3Signed <base64url>.<sig>").
Build a Web3Signed Authorization header value.