Joseph Donald Mascis Jr. (born December 10, 1965), better known as J Mascis, is an American musician who is the singer, guitarist and main songwriter for the alternative rock band Dinosaur Jr. He has
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 0xbe9f96d056e90b5e9a08c25c104d99d1ee91b19a7d982d726c71f387806e5fce. Chain 2 (Bitcoin): anchored in block 953827 (2026-06-15T19:59:56Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/f37a52f6-6e0c-491a-9bb4-bc72170385f0.json and https://artists.proofprofile.net/proofs/artist/f37a52f6-6e0c-491a-9bb4-bc72170385f0.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 0xae922151d9ea23a96128ada526a13da5241bc849879a0b625cdab9c7242a833c. Chain 2 (Bitcoin): anchored in block 958733 (2026-07-19T12:51:21Z), 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/USRE19500094.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x305af78bd683c0c79c84fafab8dcde89e6214edcbbd736cf4be32bca434972ac. Chain 2 (Bitcoin): anchored in block 958842 (2026-07-20T07:48:27Z), 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/USRE19500095.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x51a219043d434f3e629553a3c1e6ec355ec7973dc3a564c33712ef4f10caa2cd. Chain 2 (Bitcoin): anchored in block 958792 (2026-07-19T22:55:52Z), 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/USRE19500096.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x8035545bdfa00868dace66b22bd1517f797b8dd38f349f47b5487fccc7eb1d91. Chain 2 (Bitcoin): anchored in block 959132 (2026-07-22T13:20:46Z), 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/USRE19500099.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x308dba7330f791b02b732d664dfe094b50680360cb14a58fbfb6c5db3a4184fe. Chain 2 (Bitcoin): anchored in block 956545 (2026-07-03T19:59:51Z), 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/USRE19500100.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x6a1c4bc8ebd895c06cad11385bb2fa2977e13fc571e58f445204d85e99196c99. Chain 2 (Bitcoin): anchored in block 959084 (2026-07-22T00:50:00Z), 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/USRE19500102.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x514ba5df39cf71fcac91a8e205e73cff5803bc54cc7fdfbb0fd6a75a9f3be99c. Chain 2 (Bitcoin): anchored in block 956856 (2026-07-06T01:25:57Z), 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/USRE19500103.
J Mascis Live at CBGB's: The First Acoustic Show
What Else Is New? - Live from CBGB's 12/93
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb1858dc785d25f55ac9b40c46868d54f48dd8c4e3b9c3c56017f9dffdc7a452a. 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/GBAHT0600254.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xc1f51e9a3eb8569a1a23d7711e0c0d6ec21cf1136d483c365e479ba7f896343f. 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/GBAHT0600255.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x9868c5ba21eb7d236b7680359cdff6f96ad12e2e962c92698500443ac5294b70. Chain 2 (Bitcoin): anchored in block 957819 (2026-07-13T07:53:33Z), 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/GBAHT0600256.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x027217356ba280c7487fd2f6b1052d72760930d6f9b7b1feb1af049003d91c28. Chain 2 (Bitcoin): anchored in block 957064 (2026-07-07T16:43:08Z), 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/GBAHT0600257.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x51b1c835a58dbae442f1e643e697e432d5a0095dee21c93272ec2e8dcffcd8db. 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/GBAHT0600258.
Every Mother's Son - Live from CBGB's 12/93
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x9ef3f3819e3f49f0486e9da9e35fdc6b5b2f687c93cf11426064e3673be09327. 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/GBAHT0600259.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x11da3f385ae0a6b07e8d720b49b3a551ecdd68c4b6cc9c15ceeb2bb202edbffc. Chain 2 (Bitcoin): anchored in block 960111 (2026-07-29T13:21:01Z), 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/GBAHT0600260.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe369b7b73cfd5293f86226b53b04e7b7611b102d93019be3ec1c6f5bc142aeef. Chain 2 (Bitcoin): anchored in block 960254 (2026-07-30T12:06:10Z), 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/GBAHT0600261.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb74841e5a51eb19fa4768781d2f029fd963b55a453ae3f58d1215d4fa1d83730. 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/GBAHT0600262.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x0b72272fa983e155d5a3781146c21c3d0f4f35d6fd13289b552cd48f1ff34a4a. Chain 2 (Bitcoin): anchored in block 957043 (2026-07-07T13:52:39Z), 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/GBAHT0600263.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x032d07272d0453e3d113c475b6da341d8587e660f3c44bbb40872080c22e697b. Chain 2 (Bitcoin): anchored in block 957052 (2026-07-07T14:50:41Z), 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/GBAHT0600264.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x2e238e296a0bc790a3fe47a3bbb70ee0645b269e14b687be55796790306be606. 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/GBAHT0600265.
Fed Up And Feeling Strange (Live And In Person 1993-1998)
Hand It Over (2019 Expanded & Remastered Edition)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x1b9d525855f2f36f113e7fd0a0126a66db7e9e79acbd4437586f81f5a184c0f4. 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/GBBLY1903657.