{"document_id":"BLC-STUDY-0151","slug":"ouroboros-praos","title":"Ouroboros Praos: An Adaptively-Secure, Semi-synchronous Proof-of-Stake Protocol","authors":"Bernardo David, Peter Gaži, Aggelos Kiayias and Alexander Russell","year":2018,"date_label":"2018","publisher":"Bernardo David, Peter Gaži, Aggelos Kiayias and Alexander Russell","paper_type":"Design paper","category":"Consensus","topics":["Consensus"],"source_url":"https://eprint.iacr.org/2017/573","source_label":"ePrint 2017/573","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":"Source cited by the 2018 study. The study is the reading. This page does not add a second essay.","doi":null,"rights_status":"Official external source only","source_status":"Official source","use_status":"Metadata and commentary only. The reading is the study page.","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":"Praos hides who the slot leader is until they speak, and it tolerates a semi-synchronous delay, so an adaptive adversary cannot target the leader in advance.","canonical_url":"https://blockchainlab.com/whitepaper/ouroboros-praos","record_url":"https://blockchainlab.com/research/corpus/papers/ouroboros-praos","study_url":"https://blockchainlab.com/whitepaper/ouroboros-praos","last_reviewed":"2026-10-01","last_checked":"2026-10-01","relationships":[{"rel":"Canonical reading","label":"Ouroboros Praos study","href":"/whitepaper/ouroboros-praos"},{"rel":"Related paper","label":"Cardano","href":"/whitepaper/ouroboros"},{"rel":"Related paper","label":"Sleepy Consensus","href":"/whitepaper/sleepy-consensus"}]}