Simplified Payment Verification (SPV)
security · scaling
A lightweight verification method that checks block headers and Merkle proofs without downloading full blocks.
Simplified Payment Verification (SPV) lets a lightweight wallet verify that a transaction is included in a block without downloading and validating every full block. The wallet tracks block headers and uses Merkle proofs for transactions relevant to the user.
SPV relies on proof of work in the header chain and Merkle inclusion proofs. It can show that miners buried a transaction under work, but it does not independently verify every consensus rule the way a full node does.
SPV reduces storage, bandwidth, and startup time, making mobile wallets practical. It can be more self-verifying than a purely custodial or server-trusting wallet, but it is still weaker than running a full validating node.
SPV wallets can leak privacy when requesting relevant transactions, especially with older Bloom-filter approaches. They can also be misled by dishonest peers unless they connect to enough nodes and follow the strongest valid-looking header chain.
Related terms
Block
→A batch of valid transactions added to a blockchain, linked to the previous block by a cryptographic hash.
mining · blockchain · security
Block Explorer
→An indexed interface for looking up blocks, transactions, scripts or addresses, and other chain data.
tools · fundamentals
Merkle tree
→A Merkle tree is a binary tree of hashes that enables efficient verification of large data sets, used in blockchains for transaction inclusion proofs.
cryptography · data-structure
Confirmations
→The count of blocks confirming a transaction, usually including the block that first contains it.
security · blockchain