LibraryPrivacy2017Design paperCorpus record
Dandelion: Redesigning the Bitcoin Network for Anonymity
Dandelion. Shaileshh Bojja Venkatakrishnan, Giulia Fanti and Pramod Viswanath.
Forward the transaction along a line, in a stem phase, and only then broadcast it, in a fluff phase, so the first flood is not centred on the sender.
A reading of the public document. Not a copy of it, and not a claim about a later network that reused the name.
A wallet that claims network privacy should say whether the first hop is a flood or a stem.
The five-minute read
The defect
First-announcement of a transaction is a strong hint about who sent it, because the sender's neighbours see it first.
The rule
Forward the transaction along a line, in a stem phase, and only then broadcast it, in a fluff phase, so the first flood is not centred on the sender.
How it is put together
The stem is a path, not a flood. The fluff is the ordinary gossip. Anonymity is about the shape of the first hop, not about hiding amounts.
Where the claim stops
Dandelion is not a mixnet and not a hidden amount.
One action, walked through
- Pick a line of relays.
- Pass the transaction along that line without broadcasting.
- At a random hop, switch to flood.
- Is the first relay a flood?
The argument, unpacked
Why it is still on the desk
A wallet that claims network privacy should say whether the first hop is a flood or a stem.
After the text
Bitcoin never adopted it as a consensus rule. Some clients experimented. The paper is about the peer graph, which is not in the block header.
What has to be true
- Dandelion is not a mixnet and not a hidden amount.
- Later Dandelion++ changes the details. Cite which one.
- A spy who runs many nodes still has a statistical advantage.
What happened after the paper
Bitcoin never adopted it as a consensus rule. Some clients experimented. The paper is about the peer graph, which is not in the block header.
What to check before you use the idea
- Is the first relay a flood?
- How is the stem chosen?
- What does an observer with many connections still learn?
Terms
- Stem
- A private line of forwards before any broadcast.
- Fluff
- The later flood that actually spreads the transaction.
The problem the paper names
First-announcement of a transaction is a strong hint about who sent it, because the sender's neighbours see it first.
What the design proposes
- The stem is a path, not a flood.
- The fluff is the ordinary gossip.
- Anonymity is about the shape of the first hop, not about hiding amounts.
How the mechanism is specified
- Pick a line of relays.
- Pass the transaction along that line without broadcasting.
- At a random hop, switch to flood.
What this page does not treat as proven
- Dandelion is not a mixnet and not a hidden amount.
- Later Dandelion++ changes the details. Cite which one.
- A spy who runs many nodes still has a statistical advantage.
Why a venture studio still reads it
A wallet that claims network privacy should say whether the first hop is a flood or a stem.
This is Blockchain Lab's reading of a public design paper. It is not the paper, not a copy of it, and not an offer of tokens, equity, custody or a partnership. Later network behaviour can diverge from the text. Nothing here is investment, legal or technical advice.
Research status: Design paper. Last reviewed: 1 October 2026. This is a reading of a public paper, not investment, legal or security advice.