Slza is a Czech pop duo made up of singer Petr Lexa and guitarist Lukáš Bundil. They formed in 2014 and have since released four studio albums. History Slza emerged in 2014 with the song "Lhůta záruč
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 0x1cb5f6b7b941b7ebff80ab06c550790827d46ea7345b3a60788b73732bbc83b1. 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/c2fe084c-70d1-4fe1-9746-d7be4c790ab8.json and https://artists.proofprofile.net/proofs/artist/c2fe084c-70d1-4fe1-9746-d7be4c790ab8.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 0x0cdc87bc3b447a0a809c754771869fd51cade0a3b55bb4156bf21e14de4bf1e1. Chain 2 (Bitcoin): anchored in block 958529 (2026-07-18T09:21:41Z), 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/CZUM71500369.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x76a53a4d58976b435959c399e43c31da1a9e585947a2af5df332d50c34058d90. Chain 2 (Bitcoin): anchored in block 958152 (2026-07-15T12:00:27Z), 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/CZUM71500370.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x2874d49b3aa9d4076ab44352abea1eaa3afb3545e3dfc1cd0aa21b22c4588cf3. Chain 2 (Bitcoin): anchored in block 956634 (2026-07-04T10:04:33Z), 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/CZUM71500371.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xa42745a5455547e0d8441cc54b362baf6ba0a61580b25e0c83848aea2391b19e. Chain 2 (Bitcoin): anchored in block 958520 (2026-07-18T08:19:09Z), 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/CZUM71500375.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xbeb00e8ca4174c21c46be29f330eb4831a6866df94228c82a6d3be9f9d4e0159. Chain 2 (Bitcoin): anchored in block 956725 (2026-07-05T01:12:41Z), 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/CZUM71700264.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x32816e87a2cb26f7b50f0db18d23f12fc41e9baa61caeda77bce38ba2173b332. 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/CZUM71700265.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x660ebe4aa8dc6ca59230029ad8cc8157d6b9c0cefbb38ac9742a399fb59e1931. Chain 2 (Bitcoin): anchored in block 956634 (2026-07-04T10:04:33Z), 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/CZUM71700267.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb646d972bffec50db7dc36d40a5d4b618ed57b0ea1a0b3b9652a4146ed137ace. Chain 2 (Bitcoin): anchored in block 958969 (2026-07-21T04:58:13Z), 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/CZUM71700269.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x182e3953eb194f43c7db76768ff2fc4b84647d0f1f8028f2fcb7a5b63c9761c6. Chain 2 (Bitcoin): anchored in block 956772 (2026-07-05T10:01:46Z), 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/CZUM71700270.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x6ec2ec35b0dccc719b5f5473269964fb5d606d5301f712e1d0e5fe35d83169ca. Chain 2 (Bitcoin): anchored in block 958329 (2026-07-16T21:48:38Z), 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/CZUM71900312.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x64dd58165a45111569ec4722130993e552912296ed8f2aa65d614611f1c9c0c0. Chain 2 (Bitcoin): anchored in block 958468 (2026-07-18T00:27:51Z), 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/CZUM72000213.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x3b0a5e98d1096ff25c0075cecaae89811797f7259f43ffe798b617ffd6419958. Chain 2 (Bitcoin): anchored in block 958942 (2026-07-21T00:24:07Z), 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/CZUM72000214.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xc489904d2affa21ecc84d39559248f6e438f073c02a04c189fef79a87ac19002. Chain 2 (Bitcoin): anchored in block 956772 (2026-07-05T10:01:46Z), 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/CZUM72000216.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe6151bdaf2b45ae139322b302c63cdebddc9be601477a19812c707ba14954c18. 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/CZUM72000219.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x02285d5070b4a9c3e8cec09bcbec5905bf0ea343cb1326e67c1bb17f5b84f005. Chain 2 (Bitcoin): anchored in block 956422 (2026-07-03T01:01:38Z), 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/CZUM72000220.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x39334b688eb9155c7f9a9cc08ceca60701c8790fdf63e4db0629159b40298667. Chain 2 (Bitcoin): anchored in block 957880 (2026-07-13T16:39:18Z), 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/CZUM72300933.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x09a92fa522e8e567322f5948dc0ca4a60fbcfe8d8c9ebdcbc84eaf9681f747c3. 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/CZUM72300934.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x2d475f3dd6e0b656764b31fbde72949195101c4be74d1a6686fc458ff1f8bb0c. Chain 2 (Bitcoin): anchored in block 958137 (2026-07-15T09:47:57Z), 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/CZUM72300937.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xca42ac075cd7f7a3685f2d47f57644bc02865df95a00e9793e363da8f842baa1. Chain 2 (Bitcoin): anchored in block 958390 (2026-07-17T09:35:49Z), 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/CZUV72400331.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x19e978e0e761a52606e5e85c2bcdf11dc23edd19675fcc238e3b9b978239abe0. Chain 2 (Bitcoin): anchored in block 956725 (2026-07-05T01:12:41Z), 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/CZUM72401065.