New AmScan PC LLC, formerly known as Party City Holdco Inc., is an American chain of party supply stores founded in 1986 by Steve Mandell in East Hanover, New Jersey. Party City's headquarters are in
1. Compute SHA-256 of OTSCanonicalRecord value → must equal OTSHash 2. Open OTSProofURL → extract Bitcoin block number → must equal OTSBitcoinBlock 3. GET OTSBitcoinBlockVerifyURL → returns the Bitcoin block hash at height OTSBitcoinBlock; GET https://blockstream.info/api/block/{that hash} → its timestamp must match OTSTimestamp 4. Read CopyrightID inside OTSCanonicalRecord → must equal the CopyrightID above 5. GET OTSVerificationAPI → pre-computed 6-check result from server 6. If all match: this entity was registered on CopyrightChains at OTSTimestamp, independently verifiable on Bitcoin
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x504c872e6f62ba700161245ea63cea119841531fee15ad887f794fb4f9863edd. Chain 2 (Bitcoin): anchored in block 953807 (2026-06-15T16:39:18Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/e8886deb-1e93-495b-a0b6-ec76977630e0.json and https://artists.proofprofile.net/proofs/artist/e8886deb-1e93-495b-a0b6-ec76977630e0.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Party City Karaoke: Pop Radio Party, Vol. 4
Party City Karaoke: Great 80's Party, Vol. 6
Party City Karaoke - Rock Radio Party, Vol. 3
Party City Karaoke: Da Club Hits, Vol. 2
Party City Halloween Fright Flicks and Scary Sound Effects
Party City Thanksgiving Dinner Party Music
1. Confirm isrcCode identifies the recording in the pre-2022 source corpus and cc-db-prod record 2. GET OTSVerificationAPI → server-side canonical-record, hash, and attestation checks must pass 3. GET OTSBitcoinBlockVerifyURL → returns the Bitcoin block hash at height OTSBitcoinBlock; GET https://blockstream.info/api/block/{that hash} → its timestamp must match OTSTimestamp 4. Confirm CopyrightID is the CopyrightChains transaction hash 5. If all match: the cc-db-prod record is independently anchored on Bitcoin at OTSTimestamp
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xa42ba0fbe979216634008c1f96e5bb3aff28c0ea44920fe3941951a4fc1c396d. Chain 2 (Bitcoin): anchored in block 956551 (2026-07-03T21:18:05Z), registered by our registry partner. The server verifies the private canonical record against OTSHash without exposing internal provider keys. Confirm the public ISRC, CopyrightID, and Bitcoin evidence via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/US85C0704430.
Party City Basketball: Sports Party Music
Party City St. Patrick's Day Party Music