Blockchain Hash is it possible to repeat it again on other Block?

[macdevil007]

A newbie question...

Example:  Block 12345 got hash Hash   0000000000000000001ac4321c39d3da75489e6951137c64d1ffa42ccae885cd
     
is it possible to happen this Hash again on Block 67890?

thanks for those who will answer..

[bitperson]

Example:  Block 12345 got hash Hash   0000000000000000001ac4321c39d3da75489e6951137c64d1ffa42ccae885cd
     
is it possible to happen this Hash again on Block 67890?

It is very unlikely, as it is the block header, which is different for each block, that is being hashed. Please see https://en.bitcoin.it/wiki/Block_hashing_algorithm for the contents of the block header.

[mocacinno]

If i remember correctly, this is one of the checks a node does before accepting a block... If the hash of a new block is the same as the hash of a previous block, the new block will be rejected...
Source: my memory... Might not be 100% accurate

EDIT: do realise the odds of a collision are incredibly small

[JohnGalt]

If i remember correctly, this is one of the checks a node does before accepting a block... If the hash of a new block is the same as the hash of a previous block, the new block will be rejected...
Source: my memory... Might not be 100% accurate

EDIT: do realise the odds of a collision are incredibly small

While the odds of a collision are extremely low, they rise with an increasing difficulty. And since the number of blocks is unbounded, the probability of a collision occurring at some pojnt in the future is 100%.

[mocacinno]

While the odds of a collision are extremely low, they rise with an increasing difficulty. And since the number of blocks is unbounded, the probability of a collision occurring approaches 100%.

Sure, given an infinite timeframe, the odds become 100%, but still, the block would get rejected, so it's just the miner who mined the block with the colliding hash loses the block reward + fees for that block, and that's about all that'll happen.

In our lifetime, i doubt we'll ever see such a collision happening... My math is not good enough to calculate the exact odds tough, but it would be an extremely small number...

[macdevil007]

Thanks and appreciate your responses.. Got an idea already about Hash in Blockchain