{"document_id":"BLC-PAPER-0003","slug":"ouroboros","title":"Ouroboros: A Provably Secure Proof-of-Stake Blockchain Protocol","authors":"Aggelos Kiayias, Alexander Russell, Bernardo David, Roman Oliynykov","year":2017,"date_label":"IACR ePrint 2016/889. A proceedings version followed. This record is the ePrint, not a later Cardano paper.","publisher":"IACR ePrint","paper_type":"Design paper","category":"Consensus","topics":["Proof of stake","Slot leaders"],"source_url":"https://eprint.iacr.org/2016/889.pdf","source_label":"IACR ePrint 2016/889","legacy_pdf_path":null,"sha256":null,"sha256_note":"No hash is published. This build does not store those PDF bytes, so a checksum would be invented. Where a legacy path exists, it points at the Internet Archive copy of the old library.","version":"ePrint 2016/889. Praos, Genesis, and later network software are other documents.","doi":null,"rights_status":"Official external source only","source_status":"Official source","use_status":"Metadata and commentary only. Read the PDF at IACR.","licence":null,"licence_label":"No licence recorded. Rights status under review.","full_text":null,"full_text_reason":"Full text is not published on this page. Public availability is not a licence to republish a document. Blockchain Lab has not recorded a licence that permits an HTML transcription, a training set, or a retrieval corpus of the paper. Text on this page is Blockchain Lab's own wording, or a pointer to a study that is also Blockchain Lab's wording.","editorial_line":"Ouroboros elects slot leaders from stake and states the security argument in a synchronous model. Cardano is a later network. A staking rate is not part of the paper.","canonical_url":"https://blockchainlab.com/whitepaper/ouroboros","record_url":"https://blockchainlab.com/research/corpus/papers/ouroboros","study_url":"https://blockchainlab.com/whitepaper/ouroboros","last_reviewed":"2026-10-01","last_checked":"2026-10-01","relationships":[{"rel":"Canonical reading","label":"Ouroboros study","href":"/whitepaper/ouroboros"},{"rel":"Proposes","label":"Proof of stake","href":"/learn/concepts/proof-of-stake"},{"rel":"Protocol profile","label":"Ouroboros profile","href":"/learn/protocols/ouroboros"},{"rel":"What changed","label":"What changed after the paper","href":"/learn/what-changed/ouroboros"},{"rel":"Compare","label":"Stake and work","href":"/learn/compare/proof-of-stake-vs-proof-of-work"},{"rel":"Different rule","label":"Bitcoin","href":"/research/corpus/papers/bitcoin"}]}