Sumitra Sen (7 March 1933 – 3 January 2023) was an Indian Bengali singer and an exponent of Rabindra Sangeet. Her rendition style popularised Tagore's songs without losing the original notations. Ca
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 0xec5176bbe16815524dd79a058cdaee6ee2bd756db3216570d5f55d26e6a9323e. Chain 2 (Bitcoin): anchored in block 953867 (2026-06-16T01:09:47Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/05ebef49-91b8-4ccc-9d8c-20f48ed543cd.json and https://artists.proofprofile.net/proofs/artist/05ebef49-91b8-4ccc-9d8c-20f48ed543cd.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Sanchayan - A Collection of Tagore Songs, Vol. 1
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 0xb0bd5c1301f23e517c70533f7971194839a1efa32deb290c073e14476b2dbd0d. Chain 2 (Bitcoin): anchored in block 960288 (2026-07-30T17:41:38Z), 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/INP832102757.