Roberto Rufino (6 January 1922 – 24 June 1999) was an Argentine tango singer and actor. He was active during the genre's Golden Age of tango and is primarily known for his work with several prominent
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 0xec6b8d42ccb9170d460203e75905a64f7d76710ea51ac3d440886b808cbff6c4. 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/c4852d5f-b9e5-4cb0-a4f1-560053ee87ef.json and https://artists.proofprofile.net/proofs/artist/c4852d5f-b9e5-4cb0-a4f1-560053ee87ef.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 0xec6eb722d79caa6cc2bf874707cda2500e1304d6a22a94179376a8d316809f0c. Chain 2 (Bitcoin): anchored in block 959031 (2026-07-21T19:06:46Z), 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/ARF107300210.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x9ab1736871edb730b1025d875646008d6593f6277f5aee4364790f809357a2f3. Chain 2 (Bitcoin): anchored in block 957073 (2026-07-07T18:39:05Z), 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/ARA821000837.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe170a488112d8f659d803e106655f410082ce42ad6e82b38ff4427e28e59436b. Chain 2 (Bitcoin): anchored in block 957124 (2026-07-08T03:53:27Z), 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/ARA821000838.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x4fe21e21842ed29c564cefe6a292051be837278cb9253d30c35e7a79e24537e2. 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/ARA821000850.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x720ace32941ab0823625797958989b1d0b19cc8bc581ee28889008eee424b4d5. Chain 2 (Bitcoin): anchored in block 960362 (2026-07-31T06:58:00Z), 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/ARA821000839.
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 0xc746e7284a37ecba0bf743091f87ca5297e40e5f55f723f900c472721be49c9d. Chain 2 (Bitcoin): anchored in block 960429 (2026-07-31T16:07:24Z), 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/ARA821000840.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb3941174660d93283cb1010d8227c9310590b176ad595e6e354a129e78b1192b. Chain 2 (Bitcoin): anchored in block 960334 (2026-07-31T02:19:15Z), 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/ARA821000841.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb3c5c86606d36398616abd544b0e65880d7de4d5a390361e471a5a559a9c91ed. Chain 2 (Bitcoin): anchored in block 960337 (2026-07-31T02:51:48Z), 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/ARA821000843.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x7286552e547d522c67130636bd1ce0e69cfee5212c0f4c09d2a75139737a5200. Chain 2 (Bitcoin): anchored in block 960500 (2026-08-01T03:13:03Z), 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/ARA821000844.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x027a169affb85e2443aadd18f8e8bf8edcaadf857d1680775fde9c0269c1c318. Chain 2 (Bitcoin): anchored in block 960459 (2026-07-31T20:22:46Z), 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/ARA821000846.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x086abd9971d47372e25175e25cf26fb966d6bd17e9ee95ff76ab0e6f5c4a982f. 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/ARA821000847.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x66103272090ed5bb2282cb4a36558121cb9067c128476745a4bc78e2fd3081c0. Chain 2 (Bitcoin): anchored in block 960294 (2026-07-30T18:46:00Z), 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/ARA821000848.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe3643d353e3412c8b8ed26ef4191c384a13bb4ce336978c22e4733ae21a56e18. Chain 2 (Bitcoin): anchored in block 960340 (2026-07-31T03:15:04Z), 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/ARA821000852.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd8868bdb95b2bb7488eb5e5e561ca053a44babb5268896bf87821ddea15090d5. 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/QM6P41414934.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe8a7e25aaac212bf4c7e8005e13b73cff431d24595938b4ce4a7b6a5dfba34be. Chain 2 (Bitcoin): anchored in block 957118 (2026-07-08T03:20:19Z), 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/ART340900188.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5dce95b03796123ca7c145d4b941c20b584907b3b2a276a03058834eb66c47c8. 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/ARA821401623.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xc8f85550f32f14b0d5000ffceae6d61be991e42cf3a6fe6b45513d3e1f042827. 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/CA5KR1705741.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xdbf1a60e758535b77a6f6fd5bb1a85528fc649241ae41b9773cc4bbfe99921f7. Chain 2 (Bitcoin): anchored in block 960095 (2026-07-29T11:07:37Z), 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/QM6P41414942.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xa13ef72b579fd54272b111115cc01a3b213e31b09c79c9f49f81cdea594402c2. Chain 2 (Bitcoin): anchored in block 960117 (2026-07-29T14:28:24Z), 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/QM6P41414930.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x2d8dae59913d66bfacdbaefe40c91d1f3fa3b0f7706a80df98d4ab6f02b115c1. Chain 2 (Bitcoin): anchored in block 960187 (2026-07-30T01:34:28Z), 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/CA5KR1800575.