Why generation coins require 100 confirmations

[konradp]

Hi,

why generation coins require 100 confirmations while there is a rule of only 6 confirmations of transactions?

[shorena]

Hi,

why generation coins require 100 confirmations while there is a rule of only 6 confirmations of transactions?

Because the block that generated the coins might get orphaned - e.g. due to another longer chain - and the coins would have never existed in the first place. AFAIK it was 120 but has been reduced to 100 blocks.

The 6 confirmations rule is arbitrary, I am fine with a single confirmation for low value TX. The more confirmations the higher the probability that the blocks containing the TX wont be orphaned and the lower the probability that a doublespeed attack is successfull.

[konradp]

Because the block that generated the coins might get orphaned - e.g. due to another longer chain

Thanks, but isn't this true for "normal" transactions as well? Then why the difference?

[CIYAM]

Thanks, but isn't this true for "normal" transactions as well? Then why the difference?

Only *blocks* are orphaned so typically a tx that has ended up in an orphaned block will just appear in the orphan's replacement block (or one very soon after it) but this is not the case with "coinbase" txs as they are tied to the one "specific" block that they were mined in (so effectively such txs are orphaned due to being unique to one specific block - so Bitcoin is being far more careful about the use of coinbase UTXOs).

[konradp]

Only blocks are orphaned so typically a tx that has ended up in an orphaned block will appear in the orphan's replacement block (or one very soon after it) but this is not the case with "coinbase" txs as they are tied to the one "specific" block that they were mined in (so effectively such txs are orphaned due to being unique to one specific block).

OK, thanks, I've got it now. But now, the difference is huge, what were the reasons behind this value?

[CIYAM]

OK, thanks, I've got it now. But now, the difference is huge, what were the reasons behind this value?

As far as I know it was another arbitrary choice but the fact that it is considerably larger reflects that the danger of a large re-org when it comes to coinbase txs is much worse than it is for normal txs.

[konradp]

OK, thanks again!