Carl Johan Severin Holmberg (9 March 1884 – 1 December 1909) was a Swedish gymnast who competed in the 1908 Summer Olympics. He was part of the Swedish team, which was able to win the gold medal in t
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 0xa029c30b69cd2f0be5a6f4573fdbb6d16c30d9f423812db020386e66b308b637. Chain 2 (Bitcoin): anchored in block 954014 (2026-06-16T22:46:20Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/346458b8-76bb-442a-81d7-c15fc40a3039.json and https://artists.proofprofile.net/proofs/artist/346458b8-76bb-442a-81d7-c15fc40a3039.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
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 0x495dc2746c6cd468b52a29d02c9a39a09da9e8f5d8cae5c113c8185c0a306bc0. Chain 2 (Bitcoin): anchored in block 957120 (2026-07-08T03:22:41Z), 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/SEUM70600386.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x13210f5ef7e78a91a1334598cd8d28064fc218b5b16f38b2cf265f0f38c442eb. Chain 2 (Bitcoin): anchored in block 957145 (2026-07-08T08:56:20Z), 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/SEVCE0500210.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5c547c7fb334f6dedb82d70e77d246657049e4eed4e3fc14bbcc7cf3215551c6. Chain 2 (Bitcoin): anchored in block 960509 (2026-08-01T04:30:37Z), 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/SEUM70700342.
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 Note: an OTS proof may carry multiple Bitcoin attestations; OTSBitcoinBlock is the earliest confirmed one — a later attestation inside the proof corroborates it and is not a mismatch
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xaad0816d42d80c558e849d7eac63809055e1e63c4c92600ddb0833b443c08ac0. Chain 2 (Bitcoin): anchored in block 960473 (2026-07-31T22:27:44Z), 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/SEUM70601354.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd13336402a35ca1efadf73ceb07032c43ce3eaaca66e413ef45207ccaa7a3029. Chain 2 (Bitcoin): anchored in block 960427 (2026-07-31T15:59:18Z), 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/SEUM70601353.