{"name":"Agent Embassy receipt signer","signer":"0xA2168a05161C5B982ec7E96b2b55c08f98d3a506","scheme":"eip191-personal-sign","signs":"sha256(canonical_receipt_json)","canonicalization":"JSON with sorted keys, excluding the entire proof stage (it is metadata about the signing)","verify":"recompute sha256(canonical receipt), ecrecover(signature), compare to signer","key_separation":"Dedicated receipt-signing key. Cannot move funds. Not the treasury key."}