thumb|right|Makro in Kraków, Poland thumb|right|Makro in Reading, England thumb|right|Makro with previous logo in Częstochowa, Poland thumb|right|Previous Makro logo (1993–2014) Makro is a Dutch inter
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 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 0xda2f60fbc0f6b8e1ec9949a98a77a258ca925795bb9ccf2778fc622e2c60b20c. Chain 2 (Bitcoin): anchored in block 953407 (2026-06-12T19:24:56Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/d2cf04c7-87ff-4d03-a972-e91fe0640cf2.json and https://artists.proofprofile.net/proofs/artist/d2cf04c7-87ff-4d03-a972-e91fe0640cf2.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 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 0xf70db77382fa9aaaaeb747317408b9bb0a402e51c217f51c5f4a43b860e6264e. Chain 2 (Bitcoin): anchored in block 956474 (2026-07-03T08:56:35Z), 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/QM4TW1917085.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x45ae5bc5c311cf8e13843783a7e57d78f965214904547ca6d9fc9c5893ab39bc. Chain 2 (Bitcoin): anchored in block 958444 (2026-07-17T19:12:23Z), 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/ES71G1930441.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x4744825f12bde59641d2e3ba22a76b36319172e8f05696db89caf635dba62ab4. Chain 2 (Bitcoin): anchored in block 956725 (2026-07-05T01:12:41Z), 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/ES71G1948793.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x4744825f12bde59641d2e3ba22a76b36319172e8f05696db89caf635dba62ab4. Chain 2 (Bitcoin): anchored in block 956375 (2026-07-02T16:51:38Z), 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/ES71G1948793.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb270060f5ba58f14c53e9f832c01cbe8c4dec0660ddf5aaae0ffb98ac340bdd8. Chain 2 (Bitcoin): anchored in block 958444 (2026-07-17T19:12:23Z), 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/ES71G2131993.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xdba864ab3ccfc3cac5cf65d8ee85ee29b580944389d8b556ba92f242a8e0c435. Chain 2 (Bitcoin): anchored in block 958340 (2026-07-17T00:53:26Z), 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/ES71G2145666.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xf47eaa88f3b12bdc1a72555b086cb8d71a4236a90ea9b4994f60f432c706c1ca. Chain 2 (Bitcoin): anchored in block 958388 (2026-07-17T09:14:21Z), 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/ES71G2211279.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x8a8cd51f0385d1e7886131da94c03ccb3d8244d169a6302be09c7333d4546da2. Chain 2 (Bitcoin): anchored in block 958300 (2026-07-16T16:14:30Z), 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/ES71G2223535.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x51ce38d3a5b2822c4d8fa3d4fc561239b8f5cd4fe6a8f59a43e8c553eded8532. Chain 2 (Bitcoin): anchored in block 958600 (2026-07-18T19:24:05Z), 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/ES71G2317290.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x138126e8584620a28d4dfd8428852465ffc4664c9a28adba198989278f5a8ab2. Chain 2 (Bitcoin): anchored in block 956420 (2026-07-03T00:42:11Z), 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/ES64E2461467.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x35c756e9cc7a5f2b102bc554b21d7c4ed80277cfab60e02ddc010d827a4b9254. Chain 2 (Bitcoin): anchored in block 958110 (2026-07-15T06:57:12Z), 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/ES64E2483805.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x3b72128d1a34885e7f8ae57470d3ee6d6650e4a951ef809fc3bf7a9df83241e3. Chain 2 (Bitcoin): anchored in block 956634 (2026-07-04T10:04:33Z), 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/QZW9L2442156.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x0ab7f3c2068c612f9349f87402bbc909b28d1dfbfe1b2f5b3a75e2c1b7010e44. Chain 2 (Bitcoin): anchored in block 957882 (2026-07-13T16:48:10Z), 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/ES64E2494540.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xf8cc39125dfb6d09b396d6519cecb833b622ac6300978e23bfef4089ef143cc8. Chain 2 (Bitcoin): anchored in block 958137 (2026-07-15T09:47:57Z), 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/QZW9L2452848.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x2ae69573203f0c373367e4649605187efc0a3840db726629b3ede77e5455de72. Chain 2 (Bitcoin): anchored in block 958176 (2026-07-15T17:14:36Z), 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/QZW9L2452850.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xc72c856962752b97e2de2cc58dae9e973c910b037a7cd96a3b128c63c2e9e88d. Chain 2 (Bitcoin): anchored in block 956420 (2026-07-03T00:42:11Z), 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/QZW9L2452851.