Sun Ju-kyung (; born January 19, 1991), better known by his stage name Ugly Duck (), is a South Korean rapper and singer. He released his debut album, Scene Stealers with Jay Park, on July 13, 2016.
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 0xc28434631caef267ee0edbbd7de2e77faa0b4030fe8ec4c38cc430d323e4d71b. 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/dd29667a-853b-403b-9f84-279afd7f9569.json and https://artists.proofprofile.net/proofs/artist/dd29667a-853b-403b-9f84-279afd7f9569.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 0x9ab765c01dca0b611bcdeee8f4ea85a125a4a1011751bb4776c62578c6b4eca6. 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/KRC711800030.
Tell Me What You Saw (Original Television Soundtrack), Pt.5
Tell Me What You Saw 본 대로 말하라 (Original Television Soundtrack), Pt.5
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x962c854d6f4e40f1c87a5900909642ce7ab83b95289d9aa7d892ffa72a00fa4e. 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/KRC391800019.
Slide (feat. Puff Daehee, Ugly Duck & Devita)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x85aed75e4851448070fc1953ab04a5e4ee940a9accd8b2bb292fe0ba261750a2. Chain 2 (Bitcoin): anchored in block 960203 (2026-07-30T03:35:13Z), 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/TCJPW2355835.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x556ef62d9e7727448d7d97560c71daa88200a933183393ab655bde1e171a4dfa. 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/KRA351507471.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xbf8fe27fc7114cf7f5cfc9b32efa8fd004451cb2ae2b22b04ff11efec917d0ed. 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/KRA351505941.
F*CKBOY (Feat. Sik-K, BewhY & Ugly Duck)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xc69ab85ff67666ad532a0d74bac4f8e36b16d6ddbacf159f07cb97b5f4b6a021. 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/KRA351507477.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd70104bdd7844443b0e8593fda517d91d599b0931121452a945f689bc8d7a09d. 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/KRA351507480.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd5e353c2e019e2c0c841d611cba0ed519680ed887f892b6cab410a11a467b0ee. 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/KRC711900050.
Cruz (Feat. Loopy, PUNCHNELLO, Ugly Duck)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd967d1ade41b1e099ce4d209c18712b6dcbb0175fbb5fb93931f37138588da22. 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/KRA401700033.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x6d0e7a507c569ff8d5563be12207b727b3e49faa46b2401d479af6fa391a0a1b. 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/KRA341519782.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x2e5cb05ca3ff587f54d0e9bc6c455aa648528941e50f0e2f02af53f340cb8320. 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/KRF152000010.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x3c086a1097bc4ab93e1c2305bf033f45c27ed09bdaf2e9bef8db375686dc2731. Chain 2 (Bitcoin): anchored in block 960138 (2026-07-29T19:35:34Z), 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/KRB471500559.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x835f247af318160031ddeca5552493578800606ba21292c4b92e912da2ff97df. 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/KRB471500371.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x45a92946fa11664e6d853a656a0492b2b3909bc4730e7d199d441cbdd2f47c99. 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/KRC711800054.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x3f6dc61823dde22152fbf16515feaf8f07179e0c20e8866d90447477c3c52f7a. 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/KRC711700033.