Gugudan (), also stylized as gu9udan or gx9, was a South Korean girl group formed in 2016 by Jellyfish Entertainment and the company's first girl group. The group debuted on June 28, 2016, with their
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 0xb57c1075731db7a0f0fc9e5cb169d0f9ff01702f236287a46269f392c951e735. 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/180cca37-6637-4e09-937a-2c091fe73e43.json and https://artists.proofprofile.net/proofs/artist/180cca37-6637-4e09-937a-2c091fe73e43.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 0x58f83939d9e9f756ebe687efb50ef892398f8d98d068cb0ce30bf0da4ac31df1. 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/KRA771800059.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x568cad43b3433eea4b736cddb97e3e58d2095dd1ac54fd755e9c84b398978654. 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/KRA771800060.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb6bda0247c537dcfe4826d3175b3f86f5bc3e756a8da0122d58e131264860827. 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/KRA771800061.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb09992808906e8f975636c20668db2d8cd25ef8407ce8e926d7e336d88af8553. 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/KRA771800062.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xf729cf92c7fe35f485504e154c5901c9b60777ac484e5d72400ddb9742628313. 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/KRA771800063.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x87b4e9b625f1bd72d0f8490802e2eddb26990a31b529fbaa1ebd18538eb080a9. 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/KRA771800064.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x9a5fddf0d9265535b71a2abc3bc0c05cba9b72ec34ac283c5f4a8e77887f65e5. 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/KRA771800012.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x722fc3b761e499be6d54e2ef7786e2e7b70a141ce99186351ecf47747a9b3156. 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/KRA771800013.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x9369dd35ca84400971bbec80debba7d32238771a794ede220b60853274a1a91e. 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/KRA771800014.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x42ac4f81ded75882bd43fefb4cd7aaf731a22d8ad06ce775384e3990d2203899. 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/KRA771800015.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x509fb30ce240e572a5543263710eb4742762c3962ad87cfc7200d1cc8fe16573. 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/KRA382050130.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd72290d43eb8a895c670fb76c269445a5c6a91148f435d31cf3d5c0e885c2ca7. Chain 2 (Bitcoin): anchored in block 953515 (2026-06-13T12:53:06Z), 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/KRA771700053.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x9ccf1cc689b42cd4f1bd3167c7a73ce2b44ea7a07249b0781cea1ca30b762253. 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/KRA771700054.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xc6ab5eb075a68e9e3b80a653050b6a02029483d8216df66277e24b0ce182a1fe. 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/KRA771700055.
School 2017 Pt.1 (Original Television Soundtrack)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb6789287ddbfb5f2316d87ed88d9759f8639d01b827a9524e71568a6efea4015. 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/KRA251700602.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb590ef72a3398f062ede848ccb1ba3d6cd6a8bd4e096ded72132e988473b8789. 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/KRA771700025.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xc8b5ecad8068eef79212c1d733bec771effacf1d4daea26647506e57516838f4. 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/KRA771700026.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x7f6609fc98f7f2f14d9ed586f149ea8b889876fb08e15eeb96876845708bb501. 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/KRA771700027.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xae7294af8794f5b8fbe2e3290f53e7cefe702491c83db5d7d844c185c715c98e. 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/KRA771700028.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x52fcba6589c776a4539d64ce4b03b5336a91d136022707a2b6500f6601fd2a92. 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/KRA771700029.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x2136aeabc158dd21821e5607c65e46164dd32e793dca81e6d40e00eec41c719d. Chain 2 (Bitcoin): anchored in block 953515 (2026-06-13T12:53:06Z), 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/KRA771600009.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x32bb465ef2ed5df52498c284803019682169acf4d840cb2072c76b00aea2dfe6. 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/KRA771600010.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x557fe896d1854ae31b20d77d9a248b9c68a51c4969563493e27e99d968ae8452. Chain 2 (Bitcoin): anchored in block 956375 (2026-07-02T16:51:38Z), 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/KRA771600011.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x19547548866cf6f8eee67cac70551327da256864b61516e78948a6b6f72c7a71. 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/KRA771600012.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x44c33843ff33698d2edec6764e0474394af6b209fb390dd3ede17d2884bee228. 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/KRA771600013.