For example, if the maximum possible hash value is .
In the example given above, you will produce a successful hash on average every other try.
This system is used to protect against double spending and modification of previous transaction records.
Each full node in the Bitcoin network independently stores a block chain containing only blocks validated by that node.
In the following documentation, some strings have been shortened or wrapped: “[…]” indicates extra data was removed, and lines ending in a single backslash “\” are continued below.
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Chaining blocks together makes it impossible to modify transactions included in any block without modifying all following blocks.
As a result, the cost to modify a particular block increases with every new block added to the block chain, magnifying the effect of the proof of work.
Questions about Bitcoin development are best asked in one of the Bitcoin development communities.
Errors or suggestions related to documentation on can be submitted as an issue or posted to the bitcoin-documentation mailing list.
The Developer Guide aims to provide the information you need to understand Bitcoin and start building Bitcoin-based applications, but it is not a specification.