{"id":31950680,"url":"https://github.com/nulltea/contangle-zkcp","last_synced_at":"2026-04-19T06:39:14.943Z","repository":{"id":38027722,"uuid":"500112247","full_name":"nulltea/contangle-zkcp","owner":"nulltea","description":"Universal Zero Knowledge Contingent Payments (on hold)","archived":false,"fork":false,"pushed_at":"2022-09-05T14:02:26.000Z","size":233,"stargazers_count":2,"open_issues_count":0,"forks_count":0,"subscribers_count":2,"default_branch":"main","last_synced_at":"2025-10-14T12:45:53.757Z","etag":null,"topics":["bitcoin","cryptography","ethereum","payment","zero-knowledge"],"latest_commit_sha":null,"homepage":"","language":"Rust","has_issues":true,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":"mit","status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/nulltea.png","metadata":{"files":{"readme":"README.md","changelog":null,"contributing":null,"funding":null,"license":"LICENSE","code_of_conduct":null,"threat_model":null,"audit":null,"citation":null,"codeowners":null,"security":null,"support":null}},"created_at":"2022-06-05T13:56:50.000Z","updated_at":"2024-06-04T11:16:14.000Z","dependencies_parsed_at":"2022-07-18T02:17:00.530Z","dependency_job_id":null,"html_url":"https://github.com/nulltea/contangle-zkcp","commit_stats":null,"previous_names":["nulltea/contangle-zkcp"],"tags_count":0,"template":false,"template_full_name":null,"purl":"pkg:github/nulltea/contangle-zkcp","repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/nulltea%2Fcontangle-zkcp","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/nulltea%2Fcontangle-zkcp/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/nulltea%2Fcontangle-zkcp/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/nulltea%2Fcontangle-zkcp/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/nulltea","download_url":"https://codeload.github.com/nulltea/contangle-zkcp/tar.gz/refs/heads/main","sbom_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/nulltea%2Fcontangle-zkcp/sbom","scorecard":null,"host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":286080680,"owners_count":31997804,"icon_url":"https://github.com/github.png","version":null,"created_at":"2022-05-30T11:31:42.601Z","updated_at":"2026-04-18T20:23:30.271Z","status":"online","status_checked_at":"2026-04-19T02:00:07.110Z","response_time":55,"last_error":null,"robots_txt_status":"success","robots_txt_updated_at":"2025-07-24T06:49:26.215Z","robots_txt_url":"https://github.com/robots.txt","online":true,"can_crawl_api":true,"host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":["bitcoin","cryptography","ethereum","payment","zero-knowledge"],"created_at":"2025-10-14T12:45:38.006Z","updated_at":"2026-04-19T06:39:14.926Z","avatar_url":"https://github.com/nulltea.png","language":"Rust","funding_links":[],"categories":[],"sub_categories":[],"readme":"# Contangle\n\nThis project provides a suite of cryptographic and networking components for enabling efficient zero-knowledge contingent payments (ZKCP).\n\nZKCP is a transaction protocol that was first proposed by [Gregory Maxwell](https://github.com/gmaxwell) as a means of making conditional payments on the Bitcoin network. More specifically, it allows a buyer to purchase information from a seller in a manner that is private, fair and doesn’t require trusting anyone: the expected information is transferred if and _only_ if the payment is made.\n\nZKCP was [first](https://bitcoincore.org/en/2016/02/26/zero-knowledge-contingent-payments-announcement/) put into use to buy solved Sudoku for 0.10 BTC. Since then the underlying cryptography matured and thereby the idea of fully trust-less conditional payments become much more practical.\n\nThe innovation of Contangle goes from employing multiple novel cryptographic protocols such as Adaptor Signatures \\[[Fourn'19](https://github.com/LLFourn/one-time-VES/blob/master/main.pdf), [EEE'20](https://eprint.iacr.org/2020/845)\\] for scriptless conditional payments, Recursive ZK-SNARKs \\[[BCTV'14](https://eprint.iacr.org/2019/1021.pdf)\\] for efficient proofs generation without trusted setup \\[[BGH'19](https://eprint.iacr.org/2019/1021.pdf)\\], which proved to be especially problematic in the context of real-world ZKCP protocols \\[[CGGN'17](https://eprint.iacr.org/2017/566)\\].\n\n\n## Protocol\nThe high-level flow of ZKCP protocols is as such:\n1. Alice generates a key pair $(sk, pk)$ and encrypts data with $pk$ inside the circuit to generate Proof of Encryption (*PoE*) and Proof(s) of Property (*PoPRP*). She then sends proofs, and ciphertext to Bob.\n2. Bob verifies given proofs and signs the transaction $tx$ that transfers coins to Alice’s address\n3. Bob sends $tx$ into a special fair-exchange channel $C_{FE}$. Alice sends $sk$ into $C_{FE}$. $C_{FE}$ ensures that either both parties receive desired or no one at all.\n4. Bob uses $sk$ and decrypt purchased data from the ciphertext, while Alice broadcasts signed transaction $tx$ on Bob's behalf, thereby gets paid.\n\nPlease see the [protocol documentation](/docs/protocol.md) for more details on how Contangle implements the above framework.\n\n## License\nMIT\n","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fnulltea%2Fcontangle-zkcp","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fnulltea%2Fcontangle-zkcp","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fnulltea%2Fcontangle-zkcp/lists"}