Explain ARK like I'm 5


  • Alice sends money to the bank and in return receives a check from the bank that she can redeem anytime anywhere (not only on this bank).
  • If Alice wants to pay Bob using Ark, she can ask the bank to pay Bob, and in return she will endorse their check back to the bank.
  • The bank can only redeem Alice's check if it shows proof of payment to Bob.
  • Bob receives a check from the bank that he can redeem anytime anywhere.


The first step is for Alice to lift her coins. This is an atomic swap where she will give up a UTXO (+ fees) to receive a vUTXO from the ASP at the same time. The ASP makes a special transaction, called pool transaction (Pool TX), where it mixes UTXOs from many users (among other things) and creates a shared UTXO as well as many off-chain vUTXOs for each of those users including one for Alice.

In this example, Alice, Bob and Carol are "lifting" 1 BTC each to Ark:

Deep dive


Alice then instructs the ASP to take her vUTXO and pay Bob. She will only need to know Bob's address. This payment is also atomic and private. The ASP does not know which vUTXO belongs to which user and blindly mixes them to produce another anonymous vUTXO set. Ark's magic occurs in the fact that the post-mix vUTXOs can only be claimed by the intended recipients even though the ASP has no idea who owns them. Put another way, the ASP is simply coordinating blind coinjoin rounds. Bob does not have to be online to receive the funds, can claim them at any time, transfer them to others, or move them on-chain.

Now let's imagine Alice wants to send Eve 1 BTC using Ark:

Alice forfeits its vUTXO to the ASP and in return Bob receives a vUTXO

Deep dive

To be continued...