Does AMGNx / 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":26247670,"chain":"ethereum","checked_at":"2026-10-22T10:51:35Z","dev":false,"expires_at":"2026-10-23T10:51:35Z","issuer":"Backed xStocks","pool":{"base":{"address":"0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48","balance":"19174573","decimals":6,"symbol":"USDC"},"chain":"ethereum","dex":"uniswap-v4","pool":"0x7cb88db777a9d284ca2ae0ca238090d1ca136995b590fbec09c7624f99ed88c8","quote":{"address":"0xdCD6B813D01a45de8dA9367b36cB02B2E570fDFD","balance":"42886139864919482","decimals":18,"symbol":"AMGNx"}},"quote_share_of_supply":2.472302023885502e-6,"reads":[{"block":null,"method":"eth_call","params":["0xbd216513d74c8cf14cf4747e6aaa6420ff64ee9e","poolKeys","0x7cb88db777a9d284ca2ae0ca238090d1ca136995b590fbec09"],"raw_result":"Object {\"currency0\": String(\"0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48\"), \"currency1\": String(\"0xdcd6b813d01a45de8da9367b36cb02b2e570fdfd\"), \"fee\": String(\"910000\"), \"hooks\": String(\"0x0000000000000000000000000000000000000000\"), \"tickSpacing\": String(\"18200\")}","result_hash":"317ac0aa52ada3ad1338928cc5f6765d71caeb75cc9f6ff0000c6c9a07f2b07a","slot":null},{"block":null,"method":"eth_call","params":["0x7ffe42c4a5deea5b0fec41c94c136cf115597227","getSlot0","0x7cb88db777a9d284ca2ae0ca238090d1ca136995b590fbec09c7624f99ed88c8"],"raw_result":"true","result_hash":"18d10c7d2b4b04aaf04254d1ae5d655a5dc0407cbcdd5a8c3986e985370f36ee","slot":null},{"block":null,"method":"eth_call","params":["0x7ffe42c4a5deea5b0fec41c94c136cf115597227","getLiquidity","0x7cb88db777a9d284ca2ae0ca238090d1ca136995b590fbec09c7624f99ed88c8"],"raw_result":"906820523816","result_hash":"ce678d0224a96b3446e5761a86bc6279eaeaf467723aed690190240144fab39b","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":["0xdCD6B813D01a45de8dA9367b36cB02B2E570fDFD","symbol()"],"raw_result":"Some(\"AMGNx\")","result_hash":"59cd6016b3ed3232aa6287768a658b24ba5c9e2d71fa27c3eee2b060530e4fc5","slot":null},{"block":null,"method":"eth_call","params":["0xdCD6B813D01a45de8dA9367b36cB02B2E570fDFD","decimals()"],"raw_result":"Some(18)","result_hash":"c14f173ff30df32f36fac2ea29d9a20482082428fd32b58be5433d310884f764","slot":null},{"block":26247670,"method":"eth_blockNumber","params":[],"result_hash":"bab61528b462e155868e22bcd11a07dca10e86df199165d56136aef4ffa31c7e","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(\"48102884929622515\")","result_hash":"955d2698b5625805c9842b75f836f9ce6589112761afc3b902f909239ee3b88b","slot":null},{"block":null,"method":"eth_call","params":["0xdCD6B813D01a45de8dA9367b36cB02B2E570fDFD","symbol()"],"raw_result":"Some(\"AMGNx\")","result_hash":"59cd6016b3ed3232aa6287768a658b24ba5c9e2d71fa27c3eee2b060530e4fc5","slot":null},{"block":null,"method":"eth_call","params":["0xdCD6B813D01a45de8dA9367b36cB02B2E570fDFD","name()"],"raw_result":"Some(\"Amgen xStock\")","result_hash":"dba6778382aa25829ab49ded42ddcd1fb9f1b44d2c20c2f9c964acbe5adbf5f2","slot":null},{"block":null,"method":"eth_call","params":["0xdCD6B813D01a45de8dA9367b36cB02B2E570fDFD","decimals()"],"raw_result":"Some(18)","result_hash":"c14f173ff30df32f36fac2ea29d9a20482082428fd32b58be5433d310884f764","slot":null},{"block":null,"method":"eth_call","params":["0xdCD6B813D01a45de8dA9367b36cB02B2E570fDFD","totalSupply()"],"raw_result":"Some(\"17346642704081544508379\")","result_hash":"f1e85b884fd356476509551b0ae58bd09cbdd913ebafb09a5ac5bef4aa6af643","slot":null},{"block":null,"method":"eth_getCode","params":["0xdCD6B813D01a45de8dA9367b36cB02B2E570fDFD","latest"],"result_hash":"71ee049d0c0cab5d785d7aef2e6b591e511475fb8ef465f4d8f5335bfd412bfd","slot":null},{"block":null,"method":"eth_getCode","params":["0xdCD6B813D01a45de8dA9367b36cB02B2E570fDFD","latest"],"result_hash":"71ee049d0c0cab5d785d7aef2e6b591e511475fb8ef465f4d8f5335bfd412bfd","slot":null}],"registry_entry":{"chain":"ethereum","contract":"0xdCD6B813D01a45de8dA9367b36cB02B2E570fDFD","decimals":null,"issuer":"Backed xStocks","last_checked":"2026-10-22T10:11:43Z","name":"Amgen","official_deployments":[{"address":"0xdcd6b813d01a45de8da9367b36cb02b2e570fdfd","network":"Ethereum","wrapper_address_v2":"0x577cdb3ee4b0db1465ce5fd85fdba563e06ba7f5"},{"address":"0xdcd6b813d01a45de8da9367b36cb02b2e570fdfd","network":"BinanceSmartChain","wrapper_address_v2":"0x577cdb3ee4b0db1465ce5fd85fdba563e06ba7f5"},{"address":"0xdcd6b813d01a45de8da9367b36cb02b2e570fdfd","network":"Arbitrum","wrapper_address_v2":"0x577cdb3ee4b0db1465ce5fd85fdba563e06ba7f5"},{"address":"XsgKwBMbv8LDzEYRgbKtyqsub6QB56PQVzgTGbiGaNe","network":"Solana"},{"address":"EQDsHUrhcQgMvCvDU3a9lNHh3R9pg5rf8wFSBhAka7FI44Q2","network":"Ton"},{"address":"0xdcd6b813d01a45de8da9367b36cb02b2e570fdfd","network":"Mantle","wrapper_address_v2":"0x577cdb3ee4b0db1465ce5fd85fdba563e06ba7f5"},{"address":"0xdcd6b813d01a45de8da9367b36cb02b2e570fdfd","network":"HyperEVM"},{"address":"0xdcd6b813d01a45de8da9367b36cb02b2e570fdfd","network":"Ink","wrapper_address_v2":"0x577cdb3ee4b0db1465ce5fd85fdba563e06ba7f5"},{"address":"0xdcd6b813d01a45de8da9367b36cb02b2e570fdfd","network":"XLayer","wrapper_address_v2":"0x577cdb3ee4b0db1465ce5fd85fdba563e06ba7f5"},{"address":"0xdcd6b813d01a45de8da9367b36cb02b2e570fdfd","network":"Optimism","wrapper_address_v2":"0x577cdb3ee4b0db1465ce5fd85fdba563e06ba7f5"},{"address":"0xdcd6b813d01a45de8da9367b36cb02b2e570fdfd","network":"Monad","wrapper_address_v2":"0x577cdb3ee4b0db1465ce5fd85fdba563e06ba7f5"}],"source":"xstocks-api","source_url":"https://api.xstocks.fi/api/v2/public/assets","ticker":"AMGN"},"registry_hash":"b5dff7b8d7f5ed15e9c1f23895249910c0012b90becc15a0b62d06a6a18b1323","signer":"GJWKkiUd3zj1pJGfeE7JitiPiwDJC6XmNFvpJWJuvvpn","slot":null,"subject":"0x7cb88db777a9d284ca2ae0ca238090d1ca136995b590fbec09c7624f99ed88c8","ticker":"AMGN","verdict":{"Verified":{"issuer":"Backed xStocks","ticker":"AMGN"}},"version":1}

Signature

hR1LYMJxfVPL5Ki4+mmn0c21ArzWtKUeO6YZtiPOzRPcDWbuJkb0DhuodUMj33brqbDYcavEy0+YfSYSx114Ag==

API call

GET /api/attest/5fc6a0edfecab0ed015716345f6d0e57a038988a5cd0703476116b2689ef37f9

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.