Ramkumar Chattopadhyay (1921 — 18 March 2009) was an eminent Bengali singer, composer and music director. He was well known as a classical singer with a unique repertoire of Puratani (old Bengali) son
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 0xf18b3447d8a831fddd819a60dd0d0d9d14090a93da5eb5e7ee621fb0aee15189. Chain 2 (Bitcoin): anchored in block 953871 (2026-06-16T01:46:03Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/077d1002-78a5-40ee-a488-e0e90b99dba9.json and https://artists.proofprofile.net/proofs/artist/077d1002-78a5-40ee-a488-e0e90b99dba9.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 0xf3afb4799717295bb61da8a34d906864b0931d73e2881066b5651a0157e0f5cc. Chain 2 (Bitcoin): anchored in block 957122 (2026-07-08T03:39:04Z), 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/INP832101114.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x42f074ab6a40d32f2119e0cdc11dcb61cffb04432ebe79a7dc169d2ea92020ac. 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/INP832101112.
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 0xdacf5b43122636964518a3fe5224716f870ed81531be436d409555c3c00f675f. 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/QM4TW2196128.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x3077447dcec8e2a9a885852738d2f8f4e08dd7392ab669df0b6c39b51043992b. 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/INS7E0800611.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xcf1bde4d2cd7727503c1aae53a4681d4cc42ebb920fb40fe281780b5aa70bc16. Chain 2 (Bitcoin): anchored in block 957039 (2026-07-07T12:58:18Z), 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/QMFME2017319.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x7aeda426024a424058441953182ed87e9671a592891fc506bd34179c97b1b505. 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/QMFME2017320.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x4b45e17b64adada33717aaa97a0d5c7753fa37bda7aaf025c12868d29e3db7cf. Chain 2 (Bitcoin): anchored in block 957122 (2026-07-08T03:39:04Z), 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/QMFME2017329.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5392d0d743f86a7b9ec68e77c363f69016a3d13052d3d26e7f2086fb609718ab. 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/QMFME2017330.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xc77bb07af6ed93ad732b4c55667b8eef0234e8e0f4f689342d5f93fc434a5406. Chain 2 (Bitcoin): anchored in block 960222 (2026-07-30T07:48:45Z), 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/QMFME2017318.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x10b366d209034640cf6364a6378fc04505583425946411941748c663e4d26f82. Chain 2 (Bitcoin): anchored in block 960105 (2026-07-29T12:35:17Z), 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/QMFME2017321.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x043d0d287b6c64691f39baf12e67b644ca447973977ca6a9041a6ac2cff0ec86. Chain 2 (Bitcoin): anchored in block 960418 (2026-07-31T15:20:15Z), 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/QMFME2017322.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x60fa3d59600fd5e05a92837f86d9cfe922bbeb95e9719b0e486dfda8403d68ee. Chain 2 (Bitcoin): anchored in block 960302 (2026-07-30T20:09:33Z), 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/QMFME2017323.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x988c05f335d287c4755b9722fe211800679176ddee0b973c40a90ee6a8bfc602. Chain 2 (Bitcoin): anchored in block 960344 (2026-07-31T04:14:58Z), 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/QMFME2017325.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd0068b82248024f62f7731d169a54835c58e6e7bddb6b488a27ebf87d87cc72d. Chain 2 (Bitcoin): anchored in block 960481 (2026-07-31T23:51:35Z), 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/QMFME2017328.