Crypto 101 · Crypto basics
How Crypto Transactions Work: From Send Button to Confirmation
Abstract
A crypto transaction is a signed instruction that moves coins from one address to another. After it is broadcast, miners or validators include it in a block, and each later block adds a confirmation that makes reversal harder. We walk through the life of a payment and explain how many confirmations are enough.
Keywords: transaction, confirmations, mempool, signing, finality
1. In plain English
Sending crypto has five steps. Your wallet creates a payment saying "move this amount to that address", signs it with your private key to prove you are allowed to, and broadcasts it to the network. Computers on the network check that it is valid, and miners or validators include it in the next block. Once it is in a block it has one confirmation, and every block added afterwards adds another.
Confirmations matter because they measure how hard a payment would be to undo. One is enough for small everyday amounts on many networks. For large amounts, people wait for more.
2. Go deeper
In Bitcoin's design, new transactions are broadcast to all nodes, collected into a block by miners, and accepted only if every transaction in the block is valid and not already spent; nodes show acceptance by building the next block on top [1]. Each block that follows adds a confirmation, and the probability that an attacker could catch up falls quickly with each one [2]. A transaction that has been broadcast but not yet mined waits in a pool of pending transactions and is picked according to the fee attached, which is covered in network fees.
The exact numbers differ by network. Litecoin's target block spacing is 2.5 minutes [3], Dogecoin's is one minute [4], and Bitcoin's is about ten [5]. Proof-of-stake chains reach finality differently, through attestations by validators [6].
3. What to do in practice
Send a small test amount the first time. Wait for at least the confirmations your receiver asks for. If a transaction seems stuck, check it on a block explorer using its transaction ID before sending again, because a second payment is a second payment.
4. In Scrypt Wallet
Each send shows the details before you confirm, and Activity lists your transactions with links to the explorer for that network. Live block height and target block times for each coin are on its price page.
References
- Nakamoto, S. (2008). Bitcoin: A Peer-to-Peer Electronic Cash System. Whitepaper. https://bitcoin.org/bitcoin.pdf
- Bitcoin Wiki contributors (2010). Confirmation. Bitcoin Wiki: what a confirmation is and why more confirmations mean a transaction is harder to reverse. https://en.bitcoin.it/wiki/Confirmation
- Litecoin Project (2011). chainparams.cpp. Litecoin Core source code: main-net consensus parameters (halving interval 840,000; 2.5-minute target spacing). https://github.com/litecoin-project/litecoin/blob/master/src/chainparams.cpp
- Dogecoin Core developers (2013). chainparams.cpp. Dogecoin Core source code: 60-second target spacing; AuxPoW (merged mining) effective from block 371,337. https://github.com/dogecoin/dogecoin/blob/master/src/chainparams.cpp
- Bitcoin Wiki contributors (2010). Difficulty. Bitcoin Wiki: the target is retargeted every 2,016 blocks to hold the average block interval near ten minutes. https://en.bitcoin.it/wiki/Difficulty
- ethereum.org (2022). Proof-of-stake (PoS). Ethereum developer documentation for the proof-of-stake consensus mechanism. https://ethereum.org/en/developers/docs/consensus-mechanisms/pos/
Common questions
How long does a crypto transaction take?
It depends on the network's block time and the fee. Litecoin targets 2.5-minute blocks and Bitcoin about 10 minutes, and each block adds a confirmation.
Can a confirmed transaction be reversed?
Not by anyone's decision. With enough confirmations, reversing it would require redoing the work of many blocks, which is impractical on large networks.
General education, not financial, tax or legal advice. Figures are schematic. Protocol parameters are cited to primary sources and can change; verify against the linked source before relying on them.