Does XOMx / 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":26242915,"chain":"ethereum","checked_at":"2026-10-21T18:57:14Z","dev":false,"expires_at":"2026-10-22T18:57:14Z","issuer":"Backed xStocks","pool":{"base":{"address":"0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48","balance":"59636331","decimals":6,"symbol":"USDC"},"chain":"ethereum","dex":"uniswap-v4","pool":"0x1761c296b29611dc14afdf8511c9d9ee203e5a3c5e9e30d52212d2718e279704","quote":{"address":"0xEEdb0273c5Af792745180e9fF568cD01550fFA13","balance":"383992964665847980","decimals":18,"symbol":"XOMx"}},"quote_share_of_supply":4.459301046809656e-6,"reads":[{"block":null,"method":"eth_call","params":["0xbd216513d74c8cf14cf4747e6aaa6420ff64ee9e","poolKeys","0x1761c296b29611dc14afdf8511c9d9ee203e5a3c5e9e30d522"],"raw_result":"Object {\"currency0\": String(\"0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48\"), \"currency1\": String(\"0xeedb0273c5af792745180e9ff568cd01550ffa13\"), \"fee\": String(\"890000\"), \"hooks\": String(\"0x0000000000000000000000000000000000000000\"), \"tickSpacing\": String(\"17800\")}","result_hash":"81a9cc0881805aa64ad65f1034490b647dbc10c4e4c6f21620615ff04210507a","slot":null},{"block":null,"method":"eth_call","params":["0x7ffe42c4a5deea5b0fec41c94c136cf115597227","getSlot0","0x1761c296b29611dc14afdf8511c9d9ee203e5a3c5e9e30d52212d2718e279704"],"raw_result":"true","result_hash":"18d10c7d2b4b04aaf04254d1ae5d655a5dc0407cbcdd5a8c3986e985370f36ee","slot":null},{"block":null,"method":"eth_call","params":["0x7ffe42c4a5deea5b0fec41c94c136cf115597227","getLiquidity","0x1761c296b29611dc14afdf8511c9d9ee203e5a3c5e9e30d52212d2718e279704"],"raw_result":"4785387332962","result_hash":"9d443cab6a28749f244c61af35775d1a413e29d0ad39487296167f1725b2d08c","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":["0xEEdb0273c5Af792745180e9fF568cD01550fFA13","symbol()"],"raw_result":"Some(\"XOMx\")","result_hash":"82fa5b69405aa1228b02b0f9fb81ff4d71b2a40c305f50150385f400dcf5b2aa","slot":null},{"block":null,"method":"eth_call","params":["0xEEdb0273c5Af792745180e9fF568cD01550fFA13","decimals()"],"raw_result":"Some(18)","result_hash":"c14f173ff30df32f36fac2ea29d9a20482082428fd32b58be5433d310884f764","slot":null},{"block":26242915,"method":"eth_blockNumber","params":[],"result_hash":"3c32464fd428c073ffb70b41cac63d072f4432e51b6034c537e12f0a08a008d6","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(\"48181818128643514\")","result_hash":"566582fd94f94940304432c04ea387d131c7a565da87f174f73348ed5fede785","slot":null},{"block":null,"method":"eth_call","params":["0xEEdb0273c5Af792745180e9fF568cD01550fFA13","symbol()"],"raw_result":"Some(\"XOMx\")","result_hash":"82fa5b69405aa1228b02b0f9fb81ff4d71b2a40c305f50150385f400dcf5b2aa","slot":null},{"block":null,"method":"eth_call","params":["0xEEdb0273c5Af792745180e9fF568cD01550fFA13","name()"],"raw_result":"Some(\"Exxon Mobil xStock\")","result_hash":"44a8f5690998c801a7cd033582dd7f4e381c653e44bb6c94b34f0c5986299ca8","slot":null},{"block":null,"method":"eth_call","params":["0xEEdb0273c5Af792745180e9fF568cD01550fFA13","decimals()"],"raw_result":"Some(18)","result_hash":"c14f173ff30df32f36fac2ea29d9a20482082428fd32b58be5433d310884f764","slot":null},{"block":null,"method":"eth_call","params":["0xEEdb0273c5Af792745180e9fF568cD01550fFA13","totalSupply()"],"raw_result":"Some(\"86110572180492352785278\")","result_hash":"d8c5be7e0cb62dfb9e3886f58a00674b2af2b0101624b14e363a7cdc98cb63c2","slot":null},{"block":null,"method":"eth_getCode","params":["0xEEdb0273c5Af792745180e9fF568cD01550fFA13","latest"],"result_hash":"71ee049d0c0cab5d785d7aef2e6b591e511475fb8ef465f4d8f5335bfd412bfd","slot":null},{"block":null,"method":"eth_getCode","params":["0xEEdb0273c5Af792745180e9fF568cD01550fFA13","latest"],"result_hash":"71ee049d0c0cab5d785d7aef2e6b591e511475fb8ef465f4d8f5335bfd412bfd","slot":null}],"registry_entry":{"chain":"ethereum","contract":"0xEEdb0273c5Af792745180e9fF568cD01550fFA13","decimals":null,"issuer":"Backed xStocks","last_checked":"2026-10-21T18:40:19Z","name":"Exxon Mobil","official_deployments":[{"address":"0xeedb0273c5af792745180e9ff568cd01550ffa13","network":"Ethereum","wrapper_address":"0x448bc811f60eac772775dd53421380e8d4dc4338","wrapper_address_v2":"0xe407ca0c99338d210ca06aa9e4a5eada8be442de"},{"address":"0xeedb0273c5af792745180e9ff568cd01550ffa13","network":"BinanceSmartChain","wrapper_address":"0x448bc811f60eac772775dd53421380e8d4dc4338","wrapper_address_v2":"0xe407ca0c99338d210ca06aa9e4a5eada8be442de"},{"address":"0xeedb0273c5af792745180e9ff568cd01550ffa13","network":"Arbitrum","wrapper_address":"0x448bc811f60eac772775dd53421380e8d4dc4338","wrapper_address_v2":"0xe407ca0c99338d210ca06aa9e4a5eada8be442de"},{"address":"XsaHND8sHyfMfsWPj6kSdd5VwvCayZvjYgKmmcNL5qh","network":"Solana"},{"address":"TTkpurbV2vt3dnWeKjRd47LuxYoJ14uC6X","network":"Tron"},{"address":"EQC4aTgTIycBGONrbP7vE75lRdVj-lyz8qYXc8jsMWZ2pEOv","network":"Ton"},{"address":"0xeedb0273c5af792745180e9ff568cd01550ffa13","network":"Mantle","wrapper_address":"0x448bc811f60eac772775dd53421380e8d4dc4338","wrapper_address_v2":"0xe407ca0c99338d210ca06aa9e4a5eada8be442de"},{"address":"0xeedb0273c5af792745180e9ff568cd01550ffa13","network":"HyperEVM","wrapper_address_v2":"0xe407ca0c99338d210ca06aa9e4a5eada8be442de"},{"address":"0xeedb0273c5af792745180e9ff568cd01550ffa13","network":"Ink","wrapper_address_v2":"0xe407ca0c99338d210ca06aa9e4a5eada8be442de"},{"address":"0xeedb0273c5af792745180e9ff568cd01550ffa13","network":"XLayer","wrapper_address_v2":"0xe407ca0c99338d210ca06aa9e4a5eada8be442de"},{"address":"0xeedb0273c5af792745180e9ff568cd01550ffa13","network":"Optimism","wrapper_address_v2":"0xe407ca0c99338d210ca06aa9e4a5eada8be442de"},{"address":"0xeedb0273c5af792745180e9ff568cd01550ffa13","network":"Monad","wrapper_address_v2":"0xe407ca0c99338d210ca06aa9e4a5eada8be442de"}],"source":"xstocks-api","source_url":"https://api.xstocks.fi/api/v2/public/assets","ticker":"XOM"},"registry_hash":"d2b23738a0957d6535d8cddb63373ceb6c6c963a51ba306222a0752fa56fc433","signer":"GJWKkiUd3zj1pJGfeE7JitiPiwDJC6XmNFvpJWJuvvpn","slot":null,"subject":"0x1761c296b29611dc14afdf8511c9d9ee203e5a3c5e9e30d52212d2718e279704","ticker":"XOM","verdict":{"Verified":{"issuer":"Backed xStocks","ticker":"XOM"}},"version":1}

Signature

ACnjKTqyTsWahojcY8YTQ5GX5y7nK+w0dS6mhJ/78yjRNusXKL4K4mSwwMH4G695tr9GTeRQ/E3UTyn1qfqxBg==

API call

GET /api/attest/4826c2936abd605aa3937f2f98b9b4614c974bc3e0fcb3f0df43b0c634377518

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.