What:

  • Software to manage keys and create transactions

How?

  • For “light” (SPV) wallets, instead of downloading the full blockchain, it only downloads Block Headers.
  • How do you prove you made a transaction?
    • The Merkle Root stored in the header summarises every transaction in that block. When you ask a SPV server “Did I get paid”, it sends the transaction data and “partner hashes” (i.e. Merkle Path) that links your transaction to the root.