150px|thumb|Juan Carlos Cobián Juan Carlos Cobián (1888–1953) was an Argentine bandleader and tango composer.Carlos G. Groppa The Tango in the United States: A History 2004 Page 99 "Almost 50 years la
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 0x56a5c928b2ae7cb12e153123e9e1a4c257ed5ef1760efbad774c579416864a64. Chain 2 (Bitcoin): anchored in block 953620 (2026-06-14T09:36:10Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/1f70748c-a486-41d9-94c0-3556b5ec256f.json and https://artists.proofprofile.net/proofs/artist/1f70748c-a486-41d9-94c0-3556b5ec256f.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Vintage Argentine Tangos (1928 - 1954), Vol. 2
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 0x30cc154f7889bbc8a7e69dcb6425e265474d4df6ab625261aa5360b2237893cd. Chain 2 (Bitcoin): anchored in block 956304 (2026-07-02T03:55:08Z), 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/CA5KR1575263.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xac5bca50c64e760a19aed4bd5ec46f515ec6218b78990eb8ab78ce6b3e220bff. Chain 2 (Bitcoin): anchored in block 953520 (2026-06-13T13:32:09Z), 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/CA5KR1575267.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xbc4d6a83114c5ee4a77f7720b93c2d4567d95a3100925a0a172c40d47b524fdf. Chain 2 (Bitcoin): anchored in block 956304 (2026-07-02T03:55:08Z), 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/CA5KR1800573.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x307b9b21ede74db8483958ab7ca5b20df3ab9d197317e049880274c0cb9fb3a6. Chain 2 (Bitcoin): anchored in block 959159 (2026-07-22T20:03:42Z), 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/CA5KR1800585.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x4e161c1e8ac34759fd1f6035a6d7cf544cf162a61f25d7be9141717570a7ff66. Chain 2 (Bitcoin): anchored in block 959152 (2026-07-22T18:59:00Z), 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/CA5KR1800586.
Argentina!: Tango Legends from Gardel to Piazzolla
Siete canciones populares españolas: IV. jota
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x29f1ba4a26350dd61ccc457fc63e790fafe41b0ff148a29aa7702f057adfb5b6. Chain 2 (Bitcoin): anchored in block 959155 (2026-07-22T19:29:13Z), 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/FROV61410401.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x0521d11f655a5940dd2f1e1355b299580e9cc64c04b2673bf050015e6cdafcc1. Chain 2 (Bitcoin): anchored in block 953513 (2026-06-13T12:47:07Z), 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/FROV61410419.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x9bffe3d8f6e94aa25bfe010aa934078bf6810ef4b656ca19cdca2d8f64931d6d. Chain 2 (Bitcoin): anchored in block 956889 (2026-07-06T06:56:49Z), 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/FROV61410405.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x64b2a0eb1a069c0a56866c969953abe4faabede2ae39ec62022183cc5f4332c3. Chain 2 (Bitcoin): anchored in block 956304 (2026-07-02T03:55:08Z), 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/FROV61410411.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x9bc125cac928d3629adee8ca37f953c82c080b0af4140381b724ba359bf21f43. Chain 2 (Bitcoin): anchored in block 956304 (2026-07-02T03:55:08Z), 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/CA5KR1718001.
Master of the Bandoneon: Tango Argentino and Baroque Classics
Tango of the World / Tanga Świata / Tangos der Welt / tango mundial
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xec29f45b5ba22ca47aea1fba2698be5a66abda30ed4bdab7abce198513707af6. Chain 2 (Bitcoin): anchored in block 956312 (2026-07-02T05:09:12Z), 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/PLB590600005.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x94399b93f903641211bda42aff87a0a166d7454c95f598a9e640653c5d69466e. Chain 2 (Bitcoin): anchored in block 953520 (2026-06-13T13:32:09Z), 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/QZK6H2173768.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xfcd3a41b55d72a1327609b5a953fd3642b00978e6898217ad72d11c92435d6f5. Chain 2 (Bitcoin): anchored in block 956304 (2026-07-02T03:55:08Z), 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/DEAQ71942405.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x897cc512d07d5b75012fc737e90faf125a8173d2cb69bef65182569692f02f06. Chain 2 (Bitcoin): anchored in block 956304 (2026-07-02T03:55:08Z), 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/NLA460610103.
Niebieskie róże, from “Taniec szczęścia”
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xc626f4e9c6cd28ea46ec9000bdb48c7f70ff06201daaf073c0de52b781dd6ff6. Chain 2 (Bitcoin): anchored in block 956302 (2026-07-02T03:30:09Z), 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/CA5KR1537532.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x232490c0fa4b0f077299144dd58f8d246a32f3fc6df188c00f41434f7672bd74. Chain 2 (Bitcoin): anchored in block 956304 (2026-07-02T03:55:08Z), 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/ARF119900048.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x383a7de8d40515d8cd0ce3e8c4e543b825b13b2c9c71c1654cc101212c920e0e. Chain 2 (Bitcoin): anchored in block 956304 (2026-07-02T03:55:08Z), 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/CA5KR1549625.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x80f22d0809faa5ee37e39301eaee57ce91abd20c45268116ef33521a3c4cc61c. Chain 2 (Bitcoin): anchored in block 956304 (2026-07-02T03:55:08Z), 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/ARF411101283.
Tangorama: An Anthology of 20th Century Tango, Vol. 1
Tangos y Milongas : The Heart of Argentinian Tango
El Tango-Mi Refugio - Musica del Rio de la Plata
A Los Maestros (20th Century Music for Bandoneon and Guitar)
Vuelvo al Sur (Spanish and South American Music)