Does SPYon / USDC match its issuer's published contract?

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":26223785,"chain":"ethereum","checked_at":"2026-10-19T02:58:49Z","dev":false,"expires_at":"2026-10-20T02:58:49Z","issuer":"Ondo","pool":{"base":{"address":"0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48","balance":"46171301318","decimals":6,"symbol":"USDC"},"chain":"ethereum","dex":"uniswap-v3","pool":"0x5638bbDE046EC2EFC7C8f3fd8DC5A9A1016f7EEB","quote":{"address":"0xFeDC5f4a6c38211c1338aa411018DFAf26612c08","balance":"50345090630231342358","decimals":18,"symbol":"SPYon"}},"quote_share_of_supply":0.0009402035139141236,"reads":[{"block":26223785,"method":"eth_blockNumber","params":[],"result_hash":"a5c9d98994eb18d39d3fec49a1ad8d6615dbb98bb96897d4ef9c5bdc344cab2d","slot":null},{"block":null,"method":"eth_call","params":["0x5638bbDE046EC2EFC7C8f3fd8DC5A9A1016f7EEB","token0()"],"raw_result":"0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48","result_hash":"6239f262cd1d947b947081c9eba6e8771378942478e1d48654f4f132ebb96021","slot":null},{"block":null,"method":"eth_call","params":["0x5638bbDE046EC2EFC7C8f3fd8DC5A9A1016f7EEB","token1()"],"raw_result":"0xfedc5f4a6c38211c1338aa411018dfaf26612c08","result_hash":"44b5f1443d379ebaf6b0ecdc72e5af715192041a71ba98054dc4424637fe43d7","slot":null},{"block":null,"method":"eth_call","params":["0x5638bbDE046EC2EFC7C8f3fd8DC5A9A1016f7EEB","getReserves()"],"raw_result":"false","result_hash":"076de6e730df0b4c3860877a0f619c6ac11f8aefd78313ac793a2a703c026869","slot":null},{"block":null,"method":"eth_call","params":["0x5638bbDE046EC2EFC7C8f3fd8DC5A9A1016f7EEB","slot0()"],"raw_result":"true","result_hash":"18d10c7d2b4b04aaf04254d1ae5d655a5dc0407cbcdd5a8c3986e985370f36ee","slot":null},{"block":null,"method":"eth_call","params":["0x5638bbDE046EC2EFC7C8f3fd8DC5A9A1016f7EEB","factory()"],"raw_result":"0x1f98431c8ad98523631ae4a59f267346ea31f984","result_hash":"24b698329e82b3994906dfbd01281d9a6f12f65aa59de65831657e6e928d4c80","slot":null},{"block":null,"method":"eth_call","params":["0x5638bbDE046EC2EFC7C8f3fd8DC5A9A1016f7EEB","fee()"],"raw_result":"3000","result_hash":"53232d7da9fd2a1931dcd44af08ec415dd52ab8ecc4037ef5e68eb3753978a2e","slot":null},{"block":null,"method":"eth_call","params":["0x1F98431c8aD98523631AE4a59f267346ea31F984","getPool","0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48","0xFeDC5f4a6c38211c1338aa411018DFAf26612c08","0xbb8"],"raw_result":"0x5638bbde046ec2efc7c8f3fd8dc5a9a1016f7eeb","result_hash":"3c2f0694d17a66c6c3b2e11ff6640767bb90df1d330ecb85fed22bfdf3556432","slot":null},{"block":null,"method":"eth_call","params":["0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48","symbol()"],"raw_result":"Some(\"USDC\")","result_hash":"a3c9e246b0832b52e41efce041d8614251f5e288cdd4b192e85bfd3dfcb748ff","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","balanceOf","0x5638bbDE046EC2EFC7C8f3fd8DC5A9A1016f7EEB"],"raw_result":"Some(\"46171301318\")","result_hash":"0bfbeec290b8891fd03387a23ed99a4339c832a033794e45323c22c829507cc6","slot":null},{"block":null,"method":"eth_call","params":["0xFeDC5f4a6c38211c1338aa411018DFAf26612c08","symbol()"],"raw_result":"Some(\"SPYon\")","result_hash":"3d167a822bc2707e7dd38e22388e801aa3fa8afd06c0830b7e8e9fd01f918420","slot":null},{"block":null,"method":"eth_call","params":["0xFeDC5f4a6c38211c1338aa411018DFAf26612c08","decimals()"],"raw_result":"Some(18)","result_hash":"c14f173ff30df32f36fac2ea29d9a20482082428fd32b58be5433d310884f764","slot":null},{"block":null,"method":"eth_call","params":["0xFeDC5f4a6c38211c1338aa411018DFAf26612c08","balanceOf","0x5638bbDE046EC2EFC7C8f3fd8DC5A9A1016f7EEB"],"raw_result":"Some(\"50345090630231342358\")","result_hash":"0ea7714a825dfcad33eb16c9412ecace35487c4ced6ef27255296e4b735e67bd","slot":null},{"block":null,"method":"eth_call","params":["0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48","symbol()"],"raw_result":"Some(\"USDC\")","result_hash":"a3c9e246b0832b52e41efce041d8614251f5e288cdd4b192e85bfd3dfcb748ff","slot":null},{"block":null,"method":"eth_call","params":["0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48","name()"],"raw_result":"Some(\"USD 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(\"48178308758676120\")","result_hash":"784add4a2684873edf71e0afb306f3ebc4a928d912dac23f5bccd2bfc8676358","slot":null},{"block":null,"method":"eth_call","params":["0xFeDC5f4a6c38211c1338aa411018DFAf26612c08","symbol()"],"raw_result":"Some(\"SPYon\")","result_hash":"3d167a822bc2707e7dd38e22388e801aa3fa8afd06c0830b7e8e9fd01f918420","slot":null},{"block":null,"method":"eth_call","params":["0xFeDC5f4a6c38211c1338aa411018DFAf26612c08","name()"],"raw_result":"Some(\"SPDR S&P 500 ETF (Ondo Tokenized)\")","result_hash":"cfbb201091a44bc39f2c8c4fc891ef189d76588ee10408cb469f0d43664eaab6","slot":null},{"block":null,"method":"eth_call","params":["0xFeDC5f4a6c38211c1338aa411018DFAf26612c08","decimals()"],"raw_result":"Some(18)","result_hash":"c14f173ff30df32f36fac2ea29d9a20482082428fd32b58be5433d310884f764","slot":null},{"block":null,"method":"eth_call","params":["0xFeDC5f4a6c38211c1338aa411018DFAf26612c08","totalSupply()"],"raw_result":"Some(\"53547013901960126648609\")","result_hash":"b0e59d3ec02026568002f2c0990c1d26040b112e47f8f8acce12fb3a2806e2f3","slot":null},{"block":null,"method":"eth_getCode","params":["0xFeDC5f4a6c38211c1338aa411018DFAf26612c08","latest"],"result_hash":"8538a8190a64db88a5e0ec4c95f0129f9eecd6f3a3aacb869262b82d01d123ec","slot":null},{"block":null,"method":"eth_getCode","params":["0xFeDC5f4a6c38211c1338aa411018DFAf26612c08","latest"],"result_hash":"8538a8190a64db88a5e0ec4c95f0129f9eecd6f3a3aacb869262b82d01d123ec","slot":null}],"registry_entry":{"chain":"ethereum","contract":"0xFeDC5f4a6c38211c1338aa411018DFAf26612c08","decimals":null,"issuer":"Ondo","last_checked":"2026-10-18T20:40:22Z","name":"SPDR S&P 500 ETF (Ondo Tokenized)","official_deployments":[{"address":"0xFeDC5f4a6c38211c1338aa411018DFAf26612c08","network":"Ethereum"},{"address":"0x6a708EAD771238919D85930b5a0f10454E1C331a","network":"BNB Chain"},{"address":"k18WJUULWheRkSpSquYGdNNmtuE2Vbw1hpuUi92ondo","network":"Solana"},{"address":"0x32eC2792aeC02122eDD9f28866B720db1e1c1B54","network":"HyperEVM"}],"source":"https://docs.ondo.finance/addresses.md","source_url":"https://www.dropbox.com/scl/fi/qjfxyg748mx0dwi6up86d/EXTERNAL-Ondo-GM-Tokens-Ondo-GM-Tokens.csv?rlkey=n3no1w78wrah3umsl0nr9s77i&e=2&st=spdit2q1&dl=1","ticker":"SPY"},"registry_hash":"0bd20861acb250fc115ebe98f0dbbb7c686b15c772a071c9020aa5154f2d195f","signer":"GJWKkiUd3zj1pJGfeE7JitiPiwDJC6XmNFvpJWJuvvpn","slot":null,"subject":"0x5638bbDE046EC2EFC7C8f3fd8DC5A9A1016f7EEB","ticker":"SPY","verdict":{"Verified":{"issuer":"Ondo","ticker":"SPY"}},"version":1}

Signature

7/0EddYBsZV1I0NipiOVMj5UlcVqbDfdJn6YRxztTZuqxB7qEdPHoE14yu0BZ67RSWdq2vFtRkq5Fg7AbxXBAw==

API call

GET /api/attest/cfcad0474c7ef595dc812fb073a8ddf52e346bd9a0b9547e1c45af1ac7d2e61a

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.