フルネットワークノードを実行せずに支払いを検証することが可能です。ユーザーは最長のProof-of-Workチェーンのブロックヘッダーのコピーを保持するだけで済みます。ネットワークノードに問い合わせて最長チェーンを確認し、トランザクションをそれがタイムスタンプされたブロックにリンクするマークル枝を取得できます。ユーザー自身がトランザクションを検証することはできませんが、チェーン内の場所にリンクすることで、ネットワークノードがそれを受け入れたことが分かり、その後に追加されたブロックがネットワークの受け入れをさらに確認します。 したがって、正直なノードがネットワークを支配している限り、検証は信頼できますが、攻撃者がネットワークを乗っ取った場合はより脆弱になります。ネットワークノードはトランザクションを自身で検証 "It is possible to verify payments without running a full network node. A user only needs to keep a copy of the block headers of the longest proof-of-work chain, which he can get by querying network nodes until he's convinced he has the longest chain, and obtain the Merkle branch linking the transaction to the block it's timestamped in. He can't check the transaction for himself, but by linking it to a place in the chain, he can see that a network node has accepted it, and blocks added after it further confirm the network has accepted it. As such, the verification is reliable as long as honest nodes control the network, but is more vulnerable if the network is overpowered by an attacker. While network nodes can verify transactions for themselves, the simplified method can be fooled by an attacker's fabricated transactions for as long as the attacker can continue to overpower the network. One strategy to protect against this would be to accept alerts from network nodes when they detect an invalid block, prompting the user's software to download the full block and alerted transactions to confirm the inconsistency. Businesses that receive frequent payments will probably still want to run their own nodes for more independent security and quicker verification." — Satoshi Nakamoto (2008-10-31)