What is a confirmation?

Once a block includes a transaction, the transaction sits at depth one, which is its first confirmation. Every block added after that counts as one more, so if the next block arrives, the transaction has two confirmations.

Six confirmations is a long-standing convention for Bitcoin.

• Every extra block makes it harder to reverse the transaction, because an attacker would have to rebuild every block from the transaction onward.
• An attacker's chances also depend on how much of the mining power they control.
• A transaction with no confirmations is relatively cheap to reverse.

THORChain counts confirmations on chains such as Bitcoin and Ethereum, and it holds a transfer until the count is reached. It starts counting at the block in which its nodes first see the transfer. Cosmos-style chains, which finalize blocks instantly, skip the count.

The number is set by a formula. The value of the transfer is divided by the block reward of that chain, which is the new coin a miner earns for each block. The result is multiplied by a factor set for each chain, and it is capped at a maximum set for each chain.

So a larger transfer waits for more blocks, until the cap is reached.