SPYx/USDC

QED signs a canonical JSON payload. Fetch the public key from /.well-known/qed.json, then check the signature against this payload.

Canonical JSON

{"block":26139801,"chain":"Ethereum","checked_at":"2026-10-07T10:06:34Z","dev":false,"expires_at":"2026-10-08T10:06:34Z","issuer":"Backed 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Coin\")","result_hash":"fe94af15dc887a2c9df1fb0d6d276e6c586ca9d430ffeac0d05e4baee0637fd1","slot":null},{"block":null,"method":"eth_call","params":["0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48","decimals()"],"raw_result":"Some(6)","result_hash":"c68fe6989b1835302197d0af5be845dfab10ed9f9632205eb4ab5b949b9e1a6a","slot":null},{"block":null,"method":"eth_call","params":["0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48","totalSupply()"],"raw_result":"Some(\"49102092482568430\")","result_hash":"433bce99ba63fa35614e6d6c199ba1ebdf664aa41cf05d4ce17ca0db1158fac5","slot":null},{"block":null,"method":"eth_call","params":["0x90A2a4c76b5D8c0bc892A69EA28Aa775a8f2dD48","symbol()"],"raw_result":"Some(\"SPYx\")","result_hash":"de41d2c14fa73c8e3ea34e4093b99a9165ac26bef56a7d98b711bdb990d48466","slot":null},{"block":null,"method":"eth_call","params":["0x90A2a4c76b5D8c0bc892A69EA28Aa775a8f2dD48","name()"],"raw_result":"Some(\"SP500 xStock\")","result_hash":"79ea6335245c40c23594121bcd21ed9b06c5de3e2a3ad3ae9b0b706bd912711d","slot":null},{"block":null,"method":"eth_call","params":["0x90A2a4c76b5D8c0bc892A69EA28Aa775a8f2dD48","decimals()"],"raw_result":"Some(18)","result_hash":"c14f173ff30df32f36fac2ea29d9a20482082428fd32b58be5433d310884f764","slot":null},{"block":null,"method":"eth_call","params":["0x90A2a4c76b5D8c0bc892A69EA28Aa775a8f2dD48","totalSupply()"],"raw_result":"Some(\"30151354243335401773820\")","result_hash":"356a3f04c2ff8eeb3fd17bc573caf03fb6ca67331d8b483ae4d2d8b8a45641e6","slot":null},{"block":null,"method":"eth_getCode","params":["0x90A2a4c76b5D8c0bc892A69EA28Aa775a8f2dD48","latest"],"result_hash":"71ee049d0c0cab5d785d7aef2e6b591e511475fb8ef465f4d8f5335bfd412bfd","slot":null},{"block":null,"method":"eth_getCode","params":["0x90A2a4c76b5D8c0bc892A69EA28Aa775a8f2dD48","latest"],"result_hash":"71ee049d0c0cab5d785d7aef2e6b591e511475fb8ef465f4d8f5335bfd412bfd","slot":null}],"registry_entry":{"chain":"Ethereum","contract":"0x90A2a4c76b5D8c0bc892A69EA28Aa775a8f2dD48","decimals":null,"issuer":"Backed xStocks","last_checked":"2026-10-07T09:55:09Z","name":"SP500","source":"xstocks-api","source_url":"https://api.xstocks.fi/api/v2/public/assets","ticker":"SPY"},"registry_hash":"aadf069bf783c6e3e89050ff52c148cedf72d4a34e3bf0d516c670558e656381","signer":"GJWKkiUd3zj1pJGfeE7JitiPiwDJC6XmNFvpJWJuvvpn","slot":null,"subject":"0xAfdd3BdC20A31652e48b56B73952Ca324f544575","ticker":"SPY","verdict":{"Verified":{"issuer":"Backed xStocks","ticker":"SPY"}},"version":1}

Signature

8jKZv4ss3VvjELhl1BSCNdkm1Y/SkJVBXU8AY8Y9dzm0n0pYUmnlcth18UbgRKcFJpWrvvPAkaxNqS1qFM31AA==

API call

GET /api/attest/bc44423abd7e6bfd66ae541b6562b5d2ed70859e45f8c50bfaacd08cf33401ff

1. Fetch the public key and attestation JSON, then verify the signature with the published key.
2. Canonicalize the payload with sorted object keys and no whitespace, then verify its SHA-256 attestation id.
3. Run the API call above and compare the returned payload, serial, signer, and signature with this certificate.