Does SPCXx / 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":26218686,"chain":"ethereum","checked_at":"2026-10-18T09:55:45Z","dev":false,"expires_at":"2026-10-19T09:55:45Z","issuer":"Backed xStocks","pool":{"base":{"address":"0x68fa48B1C2FE52b3D776E1953e0E782b5044Ce28","balance":"153183983920063772478","decimals":18,"symbol":"SPCXx"},"chain":"ethereum","dex":"uniswap-v4","pool":"0xba8e6701ead6b06a57fc83094b0b2d25fb504d6394f6b13a17de583d50c1ebc0","quote":{"address":"0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48","balance":"21960307093","decimals":6,"symbol":"USDC"}},"quote_share_of_supply":0.0004786999497501993,"reads":[{"block":null,"method":"eth_call","params":["0xbd216513d74c8cf14cf4747e6aaa6420ff64ee9e","poolKeys","0xba8e6701ead6b06a57fc83094b0b2d25fb504d6394f6b13a17"],"raw_result":"Object {\"currency0\": String(\"0x68fa48b1c2fe52b3d776e1953e0e782b5044ce28\"), \"currency1\": String(\"0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48\"), \"fee\": String(\"10000\"), \"hooks\": String(\"0x0000000000000000000000000000000000000000\"), \"tickSpacing\": String(\"200\")}","result_hash":"19d8fd97c8ff2af6159321da91fcd2d4087a5539330d8319d03aa9261b918e83","slot":null},{"block":null,"method":"eth_call","params":["0x7ffe42c4a5deea5b0fec41c94c136cf115597227","getSlot0","0xba8e6701ead6b06a57fc83094b0b2d25fb504d6394f6b13a17de583d50c1ebc0"],"raw_result":"true","result_hash":"18d10c7d2b4b04aaf04254d1ae5d655a5dc0407cbcdd5a8c3986e985370f36ee","slot":null},{"block":null,"method":"eth_call","params":["0x7ffe42c4a5deea5b0fec41c94c136cf115597227","getLiquidity","0xba8e6701ead6b06a57fc83094b0b2d25fb504d6394f6b13a17de583d50c1ebc0"],"raw_result":"1834112136329489","result_hash":"9d016b792c3ec3bbe1f9cbad32325362e4f5b3a9ae43e09f6c3fae6e730e1a88","slot":null},{"block":null,"method":"eth_call","params":["0x68fa48B1C2FE52b3D776E1953e0E782b5044Ce28","symbol()"],"raw_result":"Some(\"SPCXx\")","result_hash":"965a6f237aaee688ad603e4d33f980be96f2d8a203b54e7af87e31a5fa74821b","slot":null},{"block":null,"method":"eth_call","params":["0x68fa48B1C2FE52b3D776E1953e0E782b5044Ce28","decimals()"],"raw_result":"Some(18)","result_hash":"c14f173ff30df32f36fac2ea29d9a20482082428fd32b58be5433d310884f764","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":26218686,"method":"eth_blockNumber","params":[],"result_hash":"dd70bcd4a34080c9cf528dcf2f2b979f2bd9af2787a17cdf5db2ad692d625063","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(\"48209419445932854\")","result_hash":"414ffa53b29c1a4a07cbda2ced932424070953c42fc62fc77d34dfdf71d8f92d","slot":null},{"block":null,"method":"eth_call","params":["0x68fa48B1C2FE52b3D776E1953e0E782b5044Ce28","symbol()"],"raw_result":"Some(\"SPCXx\")","result_hash":"965a6f237aaee688ad603e4d33f980be96f2d8a203b54e7af87e31a5fa74821b","slot":null},{"block":null,"method":"eth_call","params":["0x68fa48B1C2FE52b3D776E1953e0E782b5044Ce28","name()"],"raw_result":"Some(\"SpaceX xStock\")","result_hash":"f3e330aa060e551d81d53f26682fa521fc98ad2f6852293752beef7a3402d2ba","slot":null},{"block":null,"method":"eth_call","params":["0x68fa48B1C2FE52b3D776E1953e0E782b5044Ce28","decimals()"],"raw_result":"Some(18)","result_hash":"c14f173ff30df32f36fac2ea29d9a20482082428fd32b58be5433d310884f764","slot":null},{"block":null,"method":"eth_call","params":["0x68fa48B1C2FE52b3D776E1953e0E782b5044Ce28","totalSupply()"],"raw_result":"Some(\"320000000000000000000000\")","result_hash":"9664b0ed2b98a8318365abf6cd02d77802f08162fd5e3fee63c8fd850a588667","slot":null},{"block":null,"method":"eth_getCode","params":["0x68fa48B1C2FE52b3D776E1953e0E782b5044Ce28","latest"],"result_hash":"71ee049d0c0cab5d785d7aef2e6b591e511475fb8ef465f4d8f5335bfd412bfd","slot":null},{"block":null,"method":"eth_getCode","params":["0x68fa48B1C2FE52b3D776E1953e0E782b5044Ce28","latest"],"result_hash":"71ee049d0c0cab5d785d7aef2e6b591e511475fb8ef465f4d8f5335bfd412bfd","slot":null}],"registry_entry":{"chain":"ethereum","contract":"0x68fa48B1C2FE52b3D776E1953e0E782b5044Ce28","decimals":null,"issuer":"Backed xStocks","last_checked":"2026-10-18T09:47:32Z","name":"SpaceX","official_deployments":[{"address":"0x68fa48b1c2fe52b3d776e1953e0e782b5044ce28","network":"Ethereum","wrapper_address_v2":"0x8e2eed8b8b5e13ea7bf38e50d7821d2c57309072"},{"address":"0x68fa48b1c2fe52b3d776e1953e0e782b5044ce28","network":"BinanceSmartChain","wrapper_address_v2":"0x8e2eed8b8b5e13ea7bf38e50d7821d2c57309072"},{"address":"0x68fa48b1c2fe52b3d776e1953e0e782b5044ce28","network":"Arbitrum","wrapper_address_v2":"0x8e2eed8b8b5e13ea7bf38e50d7821d2c57309072"},{"address":"Xs3oZwbHvqis4NYcf4YKWmEia2eC84wSiVrcYcTqpH8","network":"Solana"},{"address":"EQAAsfl1a-BA8dSSUX2VpLCveFYzDOLrJX9ll89baSbmvl2V","network":"Ton"},{"address":"0x68fa48b1c2fe52b3d776e1953e0e782b5044ce28","network":"Mantle","wrapper_address_v2":"0x8e2eed8b8b5e13ea7bf38e50d7821d2c57309072"},{"address":"0x68fa48b1c2fe52b3d776e1953e0e782b5044ce28","network":"HyperEVM"},{"address":"0x68fa48b1c2fe52b3d776e1953e0e782b5044ce28","network":"Ink","wrapper_address_v2":"0x8e2eed8b8b5e13ea7bf38e50d7821d2c57309072"},{"address":"0x68fa48b1c2fe52b3d776e1953e0e782b5044ce28","network":"XLayer","wrapper_address_v2":"0x8e2eed8b8b5e13ea7bf38e50d7821d2c57309072"},{"address":"0x68fa48b1c2fe52b3d776e1953e0e782b5044ce28","network":"Optimism","wrapper_address_v2":"0x8e2eed8b8b5e13ea7bf38e50d7821d2c57309072"},{"address":"0x68fa48b1c2fe52b3d776e1953e0e782b5044ce28","network":"Monad","wrapper_address_v2":"0x8e2eed8b8b5e13ea7bf38e50d7821d2c57309072"}],"source":"xstocks-api","source_url":"https://api.xstocks.fi/api/v2/public/assets","ticker":"SPCX"},"registry_hash":"3143486c8ed17e52c07540b096bdf4ef50abfca368b23311d9290e9923561570","signer":"GJWKkiUd3zj1pJGfeE7JitiPiwDJC6XmNFvpJWJuvvpn","slot":null,"subject":"0xba8e6701ead6b06a57fc83094b0b2d25fb504d6394f6b13a17de583d50c1ebc0","ticker":"SPCX","verdict":{"Verified":{"issuer":"Backed xStocks","ticker":"SPCX"}},"version":1}

Signature

BmyiethxfRbl/j/5cYDA4uxZfBOBW/UG8giJPMscOK+ML2z/SBYIblzt/BuPB0K3PVYkmHSI3VoJnaL72e/hBQ==

API call

GET /api/attest/25edf3bd31eae85e6ef73e0f2ea6ffff2774b5a7ef3d279bc912ec24df7bb6c4

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.