> For the complete documentation index, see [llms.txt](https://hub.bsvblockchain.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hub.bsvblockchain.org/bitcoin-protocol-documentation/specification.md).

# Specification

- [Transactions](https://hub.bsvblockchain.org/bitcoin-protocol-documentation/specification/transactions.md): Data structure composition of a transaction
- [Script](https://hub.bsvblockchain.org/bitcoin-protocol-documentation/specification/script.md): Understanding basics of Script and stack based compilation
- [Opcodes](https://hub.bsvblockchain.org/bitcoin-protocol-documentation/specification/opcodes.md): Every Script opcode — value, operand, stack effect, and era status
- [Signature Hashing](https://hub.bsvblockchain.org/bitcoin-protocol-documentation/specification/signature-hashing.md): Sighash flags and the transaction signature-hash (digest) algorithms
- [Blocks](https://hub.bsvblockchain.org/bitcoin-protocol-documentation/specification/blocks.md): Block and block-header structure, serialization, and validity
- [Consensus Rules](https://hub.bsvblockchain.org/bitcoin-protocol-documentation/specification/consensus-rules.md): The rules that define the protocol used for the blockchain
- [Protocol Upgrade History](https://hub.bsvblockchain.org/bitcoin-protocol-documentation/specification/upgrade-history.md): The consensus upgrade timeline — which validity rules apply at which height


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