{"document_id":"BLC-STUDY-0065","slug":"casper-ffg","title":"Casper the Friendly Finality Gadget","authors":"Vitalik Buterin and Virgil Griffith","year":2017,"date_label":"2017","publisher":"Vitalik Buterin and Virgil Griffith","paper_type":"Design paper","category":"Consensus","topics":["Consensus"],"source_url":"https://arxiv.org/abs/1710.09437","source_label":"arXiv:1710.09437","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 2017 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":"A finality overlay. Validators cast two rounds of votes so that a chain of checkpoints becomes justified and then final. Equivocation can be slashed. The gadget does not, by itself, propose blocks.","canonical_url":"https://blockchainlab.com/whitepaper/casper-ffg","record_url":"https://blockchainlab.com/research/corpus/papers/casper-ffg","study_url":"https://blockchainlab.com/whitepaper/casper-ffg","last_reviewed":"2026-10-01","last_checked":"2026-10-01","relationships":[{"rel":"Canonical reading","label":"Casper FFG study","href":"/whitepaper/casper-ffg"},{"rel":"Related paper","label":"Tendermint","href":"/whitepaper/tendermint"},{"rel":"Related paper","label":"HotStuff","href":"/whitepaper/hotstuff"},{"rel":"Related paper","label":"Cardano","href":"/whitepaper/ouroboros"}]}